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  • Tied up with injection implemented with setter functions

    - by puudeli
    Hi, I'm trying to use Scala as part of an existing Java application and now I run into an issue with dependencies injected with a setter method (no DI frameworks in this part of code). How is this handled in a Scala way? In Scala both val and var require to be initialized when declared but I can't do that, since the Java setters inject objects that implement a certain interface and interfaces are abstract and can not be instantiated. class ScalaLogic { var service // How to initialize? def setService (srv: OutputService) = { service = srv } Is there a way to initialize the var service so that I can later assign a dependency into it? It should be lexically scoped to be visible in the whole class.

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  • Subtle C++ mistake, can you spot it?

    - by aaa
    I ran into a subtle C++ gotcha, took me while to resolve it. Can you spot it? class synchronized_container { boost::mutex mutex_; std::vector <T> container_; void push_back(const T &value) { boost::scoped_lock(mutex_); // raii mutex lock container_.push_back(value); } ... }; scoped lock is a raii mutex lock, obtains lock on constructor, release lock in destructor. The program will work as expected in serial, but will may occasionally produce weird stuff with more than one thread.

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  • Where can these be posted besides the Python Cookbook?

    - by Noctis Skytower
    Whitespace Assembler #! /usr/bin/env python """Assembler.py Compiles a program from "Assembly" folder into "Program" folder. Can be executed directly by double-click or on the command line. Give name of *.WSA file without extension (example: stack_calc).""" ################################################################################ __author__ = 'Stephen "Zero" Chappell <[email protected]>' __date__ = '14 March 2010' __version__ = '$Revision: 3 $' ################################################################################ import string from Interpreter import INS, MNEMONIC ################################################################################ def parse(code): program = [] process_virtual(program, code) process_control(program) return tuple(program) def process_virtual(program, code): for line, text in enumerate(code.split('\n')): if not text or text[0] == '#': continue if text.startswith('part '): parse_part(program, line, text[5:]) elif text.startswith(' '): parse_code(program, line, text[5:]) else: syntax_error(line) def syntax_error(line): raise SyntaxError('Line ' + str(line + 1)) ################################################################################ def process_control(program): parts = get_parts(program) names = dict(pair for pair in zip(parts, generate_index())) correct_control(program, names) def get_parts(program): parts = [] for ins in program: if isinstance(ins, tuple): ins, arg = ins if ins == INS.PART: if arg in parts: raise NameError('Part definition was found twice: ' + arg) parts.append(arg) return parts def generate_index(): index = 1 while True: yield index index *= -1 if index > 0: index += 1 def correct_control(program, names): for index, ins in enumerate(program): if isinstance(ins, tuple): ins, arg = ins if ins in HAS_LABEL: if arg not in names: raise NameError('Part definition was never found: ' + arg) program[index] = (ins, names[arg]) ################################################################################ def parse_part(program, line, text): if not valid_label(text): syntax_error(line) program.append((INS.PART, text)) def valid_label(text): if not between_quotes(text): return False label = text[1:-1] if not valid_name(label): return False return True def between_quotes(text): if len(text) < 3: return False if text.count('"') != 2: return False if text[0] != '"' or text[-1] != '"': return False return True def valid_name(label): valid_characters = string.ascii_letters + string.digits + '_' valid_set = frozenset(valid_characters) label_set = frozenset(label) if len(label_set - valid_set) != 0: return False return True ################################################################################ from Interpreter import HAS_LABEL, Program NO_ARGS = Program.NO_ARGS HAS_ARG = Program.HAS_ARG TWO_WAY = tuple(set(NO_ARGS) & set(HAS_ARG)) ################################################################################ def parse_code(program, line, text): for ins, word in enumerate(MNEMONIC): if text.startswith(word): check_code(program, line, text[len(word):], ins) break else: syntax_error(line) def check_code(program, line, text, ins): if ins in TWO_WAY: if text: number = parse_number(line, text) program.append((ins, number)) else: program.append(ins) elif ins in HAS_LABEL: text = parse_label(line, text) program.append((ins, text)) elif ins in HAS_ARG: number = parse_number(line, text) program.append((ins, number)) elif ins in NO_ARGS: if text: syntax_error(line) program.append(ins) else: syntax_error(line) def parse_label(line, text): if not text or text[0] != ' ': syntax_error(line) text = text[1:] if not valid_label(text): syntax_error(line) return text ################################################################################ def parse_number(line, text): if not valid_number(text): syntax_error(line) return int(text) def valid_number(text): if len(text) < 2: return False if text[0] != ' ': return False text = text[1:] if '+' in text and '-' in text: return False if '+' in text: if text.count('+') != 1: return False if text[0] != '+': return False text = text[1:] if not text: return False if '-' in text: if text.count('-') != 1: return False if text[0] != '-': return False text = text[1:] if not text: return False valid_set = frozenset(string.digits) value_set = frozenset(text) if len(value_set - valid_set) != 0: return False return True ################################################################################ ################################################################################ from Interpreter import partition_number VMC_2_TRI = { (INS.PUSH, True): (0, 0), (INS.COPY, False): (0, 2, 0), (INS.COPY, True): (0, 1, 0), (INS.SWAP, False): (0, 2, 1), (INS.AWAY, False): (0, 2, 2), (INS.AWAY, True): (0, 1, 2), (INS.ADD, False): (1, 0, 0, 0), (INS.SUB, False): (1, 0, 0, 1), (INS.MUL, False): (1, 0, 0, 2), (INS.DIV, False): (1, 0, 1, 0), (INS.MOD, False): (1, 0, 1, 1), (INS.SET, False): (1, 1, 0), (INS.GET, False): (1, 1, 1), (INS.PART, True): (2, 0, 0), (INS.CALL, True): (2, 0, 1), (INS.GOTO, True): (2, 0, 2), (INS.ZERO, True): (2, 1, 0), (INS.LESS, True): (2, 1, 1), (INS.BACK, False): (2, 1, 2), (INS.EXIT, False): (2, 2, 2), (INS.OCHR, False): (1, 2, 0, 0), (INS.OINT, False): (1, 2, 0, 1), (INS.ICHR, False): (1, 2, 1, 0), (INS.IINT, False): (1, 2, 1, 1) } ################################################################################ def to_trinary(program): trinary_code = [] for ins in program: if isinstance(ins, tuple): ins, arg = ins trinary_code.extend(VMC_2_TRI[(ins, True)]) trinary_code.extend(from_number(arg)) else: trinary_code.extend(VMC_2_TRI[(ins, False)]) return tuple(trinary_code) def from_number(arg): code = [int(arg < 0)] if arg: for bit in reversed(list(partition_number(abs(arg), 2))): code.append(bit) return code + [2] return code + [0, 2] to_ws = lambda trinary: ''.join(' \t\n'[index] for index in trinary) def compile_wsa(source): program = parse(source) trinary = to_trinary(program) ws_code = to_ws(trinary) return ws_code ################################################################################ ################################################################################ import os import sys import time import traceback def main(): name, source, command_line, error = get_source() if not error: start = time.clock() try: ws_code = compile_wsa(source) except: print('ERROR: File could not be compiled.\n') traceback.print_exc() error = True else: path = os.path.join('Programs', name + '.ws') try: open(path, 'w').write(ws_code) except IOError as err: print(err) error = True else: div, mod = divmod((time.clock() - start) * 1000, 1) args = int(div), '{:.3}'.format(mod)[1:] print('DONE: Comipled in {}{} ms'.format(*args)) handle_close(error, command_line) def get_source(): if len(sys.argv) > 1: command_line = True name = sys.argv[1] else: command_line = False try: name = input('Source File: ') except: return None, None, False, True print() path = os.path.join('Assembly', name + '.wsa') try: return name, open(path).read(), command_line, False except IOError as err: print(err) return None, None, command_line, True def handle_close(error, command_line): if error: usage = 'Usage: {} <assembly>'.format(os.path.basename(sys.argv[0])) print('\n{}\n{}'.format('-' * len(usage), usage)) if not command_line: time.sleep(10) ################################################################################ if __name__ == '__main__': main() Whitespace Helpers #! /usr/bin/env python """Helpers.py Includes a function to encode Python strings into my WSA format. Has a "PRINT_LINE" function that can be copied to a WSA program. Contains a "PRINT" function and documentation as an explanation.""" ################################################################################ __author__ = 'Stephen "Zero" Chappell <[email protected]>' __date__ = '14 March 2010' __version__ = '$Revision: 1 $' ################################################################################ def encode_string(string, addr): print(' push', addr) print(' push', len(string)) print(' set') addr += 1 for offset, character in enumerate(string): print(' push', addr + offset) print(' push', ord(character)) print(' set') ################################################################################ # Prints a string with newline. # push addr # call "PRINT_LINE" """ part "PRINT_LINE" call "PRINT" push 10 ochr back """ ################################################################################ # def print(array): # if len(array) <= 0: # return # offset = 1 # while len(array) - offset >= 0: # ptr = array.ptr + offset # putch(array[ptr]) # offset += 1 """ part "PRINT" # Line 1-2 copy get less "__PRINT_RET_1" copy get zero "__PRINT_RET_1" # Line 3 push 1 # Line 4 part "__PRINT_LOOP" copy copy 2 get swap sub less "__PRINT_RET_2" # Line 5 copy 1 copy 1 add # Line 6 get ochr # Line 7 push 1 add goto "__PRINT_LOOP" part "__PRINT_RET_2" away part "__PRINT_RET_1" away back """ Whitespace Interpreter #! /usr/bin/env python """Interpreter.py Runs programs in "Programs" and creates *.WSO files when needed. Can be executed directly by double-click or on the command line. If run on command line, add "ASM" flag to dump program assembly.""" ################################################################################ __author__ = 'Stephen "Zero" Chappell <[email protected]>' __date__ = '14 March 2010' __version__ = '$Revision: 4 $' ################################################################################ def test_file(path): disassemble(parse(trinary(load(path))), True) ################################################################################ load = lambda ws: ''.join(c for r in open(ws) for c in r if c in ' \t\n') trinary = lambda ws: tuple(' \t\n'.index(c) for c in ws) ################################################################################ def enum(names): names = names.replace(',', ' ').split() space = dict((reversed(pair) for pair in enumerate(names)), __slots__=()) return type('enum', (object,), space)() INS = enum('''\ PUSH, COPY, SWAP, AWAY, \ ADD, SUB, MUL, DIV, MOD, \ SET, GET, \ PART, CALL, GOTO, ZERO, LESS, BACK, EXIT, \ OCHR, OINT, ICHR, IINT''') ################################################################################ def parse(code): ins = iter(code).__next__ program = [] while True: try: imp = ins() except StopIteration: return tuple(program) if imp == 0: # [Space] parse_stack(ins, program) elif imp == 1: # [Tab] imp = ins() if imp == 0: # [Tab][Space] parse_math(ins, program) elif imp == 1: # [Tab][Tab] parse_heap(ins, program) else: # [Tab][Line] parse_io(ins, program) else: # [Line] parse_flow(ins, program) def parse_number(ins): sign = ins() if sign == 2: raise StopIteration() buffer = '' code = ins() if code == 2: raise StopIteration() while code != 2: buffer += str(code) code = ins() if sign == 1: return int(buffer, 2) * -1 return int(buffer, 2) ################################################################################ def parse_stack(ins, program): code = ins() if code == 0: # [Space] number = parse_number(ins) program.append((INS.PUSH, number)) elif code == 1: # [Tab] code = ins() number = parse_number(ins) if code == 0: # [Tab][Space] program.append((INS.COPY, number)) elif code == 1: # [Tab][Tab] raise StopIteration() else: # [Tab][Line] program.append((INS.AWAY, number)) else: # [Line] code = ins() if code == 0: # [Line][Space] program.append(INS.COPY) elif code == 1: # [Line][Tab] program.append(INS.SWAP) else: # [Line][Line] program.append(INS.AWAY) def parse_math(ins, program): code = ins() if code == 0: # [Space] code = ins() if code == 0: # [Space][Space] program.append(INS.ADD) elif code == 1: # [Space][Tab] program.append(INS.SUB) else: # [Space][Line] program.append(INS.MUL) elif code == 1: # [Tab] code = ins() if code == 0: # [Tab][Space] program.append(INS.DIV) elif code == 1: # [Tab][Tab] program.append(INS.MOD) else: # [Tab][Line] raise StopIteration() else: # [Line] raise StopIteration() def parse_heap(ins, program): code = ins() if code == 0: # [Space] program.append(INS.SET) elif code == 1: # [Tab] program.append(INS.GET) else: # [Line] raise StopIteration() def parse_io(ins, program): code = ins() if code == 0: # [Space] code = ins() if code == 0: # [Space][Space] program.append(INS.OCHR) elif code == 1: # [Space][Tab] program.append(INS.OINT) else: # [Space][Line] raise StopIteration() elif code == 1: # [Tab] code = ins() if code == 0: # [Tab][Space] program.append(INS.ICHR) elif code == 1: # [Tab][Tab] program.append(INS.IINT) else: # [Tab][Line] raise StopIteration() else: # [Line] raise StopIteration() def parse_flow(ins, program): code = ins() if code == 0: # [Space] code = ins() label = parse_number(ins) if code == 0: # [Space][Space] program.append((INS.PART, label)) elif code == 1: # [Space][Tab] program.append((INS.CALL, label)) else: # [Space][Line] program.append((INS.GOTO, label)) elif code == 1: # [Tab] code = ins() if code == 0: # [Tab][Space] label = parse_number(ins) program.append((INS.ZERO, label)) elif code == 1: # [Tab][Tab] label = parse_number(ins) program.append((INS.LESS, label)) else: # [Tab][Line] program.append(INS.BACK) else: # [Line] code = ins() if code == 2: # [Line][Line] program.append(INS.EXIT) else: # [Line][Space] or [Line][Tab] raise StopIteration() ################################################################################ MNEMONIC = '\ push copy swap away add sub mul div mod set get part \ call goto zero less back exit ochr oint ichr iint'.split() HAS_ARG = [getattr(INS, name) for name in 'PUSH COPY AWAY PART CALL GOTO ZERO LESS'.split()] HAS_LABEL = [getattr(INS, name) for name in 'PART CALL GOTO ZERO LESS'.split()] def disassemble(program, names=False): if names: names = create_names(program) for ins in program: if isinstance(ins, tuple): ins, arg = ins assert ins in HAS_ARG has_arg = True else: assert INS.PUSH <= ins <= INS.IINT has_arg = False if ins == INS.PART: if names: print(MNEMONIC[ins], '"' + names[arg] + '"') else: print(MNEMONIC[ins], arg) elif has_arg and ins in HAS_ARG: if ins in HAS_LABEL and names: assert arg in names print(' ' + MNEMONIC[ins], '"' + names[arg] + '"') else: print(' ' + MNEMONIC[ins], arg) else: print(' ' + MNEMONIC[ins]) ################################################################################ def create_names(program): names = {} number = 1 for ins in program: if isinstance(ins, tuple) and ins[0] == INS.PART: label = ins[1] assert label not in names names[label] = number_to_name(number) number += 1 return names def number_to_name(number): name = '' for offset in reversed(list(partition_number(number, 27))): if offset: name += chr(ord('A') + offset - 1) else: name += '_' return name def partition_number(number, base): div, mod = divmod(number, base) yield mod while div: div, mod = divmod(div, base) yield mod ################################################################################ CODE = (' \t\n', ' \n ', ' \t \t\n', ' \n\t', ' \n\n', ' \t\n \t\n', '\t ', '\t \t', '\t \n', '\t \t ', '\t \t\t', '\t\t ', '\t\t\t', '\n \t\n', '\n \t \t\n', '\n \n \t\n', '\n\t \t\n', '\n\t\t \t\n', '\n\t\n', '\n\n\n', '\t\n ', '\t\n \t', '\t\n\t ', '\t\n\t\t') EXAMPLE = ''.join(CODE) ################################################################################ NOTES = '''\ STACK ===== push number copy copy number swap away away number MATH ==== add sub mul div mod HEAP ==== set get FLOW ==== part label call label goto label zero label less label back exit I/O === ochr oint ichr iint''' ################################################################################ ################################################################################ class Stack: def __init__(self): self.__data = [] # Stack Operators def push(self, number): self.__data.append(number) def copy(self, number=None): if number is None: self.__data.append(self.__data[-1]) else: size = len(self.__data) index = size - number - 1 assert 0 <= index < size self.__data.append(self.__data[index]) def swap(self): self.__data[-2], self.__data[-1] = self.__data[-1], self.__data[-2] def away(self, number=None): if number is None: self.__data.pop() else: size = len(self.__data) index = size - number - 1 assert 0 <= index < size del self.__data[index:-1] # Math Operators def add(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix + suffix) def sub(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix - suffix) def mul(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix * suffix) def div(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix // suffix) def mod(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix % suffix) # Program Operator def pop(self): return self.__data.pop() ################################################################################ class Heap: def __init__(self): self.__data = {} def set_(self, addr, item): if item: self.__data[addr] = item elif addr in self.__data: del self.__data[addr] def get_(self, addr): return self.__data.get(addr, 0) ################################################################################ import os import zlib import msvcrt import pickle import string class CleanExit(Exception): pass NOP = lambda arg: None DEBUG_WHITESPACE = False ################################################################################ class Program: NO_ARGS = INS.COPY, INS.SWAP, INS.AWAY, INS.ADD, \ INS.SUB, INS.MUL, INS.DIV, INS.MOD, \ INS.SET, INS.GET, INS.BACK, INS.EXIT, \ INS.OCHR, INS.OINT, INS.ICHR, INS.IINT HAS_ARG = INS.PUSH, INS.COPY, INS.AWAY, INS.PART, \ INS.CALL, INS.GOTO, INS.ZERO, INS.LESS def __init__(self, code): self.__data = code self.__validate() self.__build_jump() self.__check_jump() self.__setup_exec() def __setup_exec(self): self.__iptr = 0 self.__stck = stack = Stack() self.__heap = Heap() self.__cast = [] self.__meth = (stack.push, stack.copy, stack.swap, stack.away, stack.add, stack.sub, stack.mul, stack.div, stack.mod, self.__set, self.__get, NOP, self.__call, self.__goto, self.__zero, self.__less, self.__back, self.__exit, self.__ochr, self.__oint, self.__ichr, self.__iint) def step(self): ins = self.__data[self.__iptr] self.__iptr += 1 if isinstance(ins, tuple): self.__meth[ins[0]](ins[1]) else: self.__meth[ins]() def run(self): while True: ins = self.__data[self.__iptr] self.__iptr += 1 if isinstance(ins, tuple): self.__meth[ins[0]](ins[1]) else: self.__meth[ins]() def __oint(self): for digit in str(self.__stck.pop()): msvcrt.putwch(digit) def __ichr(self): addr = self.__stck.pop() # Input Routine while msvcrt.kbhit(): msvcrt.getwch() while True: char = msvcrt.getwch() if char in '\x00\xE0': msvcrt.getwch() elif char in string.printable: char = char.replace('\r', '\n') msvcrt.putwch(char) break item = ord(char) # Storing Number self.__heap.set_(addr, item) def __iint(self): addr = self.__stck.pop() # Input Routine while msvcrt.kbhit(): msvcrt.getwch() buff = '' char = msvcrt.getwch() while char != '\r' or not buff: if char in '\x00\xE0': msvcrt.getwch() elif char in '+-' and not buff: msvcrt.putwch(char) buff += char elif '0' <= char <= '9': msvcrt.putwch(char) buff += char elif char == '\b': if buff: buff = buff[:-1] msvcrt.putwch(char) msvcrt.putwch(' ') msvcrt.putwch(char) char = msvcrt.getwch() msvcrt.putwch(char) msvcrt.putwch('\n') item = int(buff) # Storing Number self.__heap.set_(addr, item) def __goto(self, label): self.__iptr = self.__jump[label] def __zero(self, label): if self.__stck.pop() == 0: self.__iptr = self.__jump[label] def __less(self, label): if self.__stck.pop() < 0: self.__iptr = self.__jump[label] def __exit(self): self.__setup_exec() raise CleanExit() def __set(self): item = self.__stck.pop() addr = self.__stck.po

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  • How to add event receiver to SharePoint2010 content type programmatically

    - by ybbest
    Today , I’d like to show how to add event receiver to How to add event receiver to SharePoint2010 content type programmatically. 1. Create empty SharePoint Project and add a class called ItemContentTypeEventReceiver and make it inherit from SPItemEventReceiver and implement your logic as below public class ItemContentTypeEventReceiver : SPItemEventReceiver { private bool eventFiringEnabledStatus; public override void ItemAdded(SPItemEventProperties properties) { base.ItemAdded(properties); UpdateTitle(properties); } private void UpdateTitle(SPItemEventProperties properties) { SPListItem addedItem = properties.ListItem; string enteredTitle = addedItem["Title"] as string; addedItem["Title"] = enteredTitle + " Updated"; DisableItemEventsScope(); addedItem.Update(); EnableItemEventsScope(); } public override void ItemUpdated(SPItemEventProperties properties) { base.ItemUpdated(properties); UpdateTitle(properties); } private void DisableItemEventsScope() { eventFiringEnabledStatus = EventFiringEnabled; EventFiringEnabled = false; } private void EnableItemEventsScope() { eventFiringEnabledStatus = EventFiringEnabled; EventFiringEnabled = true; } } 2.Create a Site or Web(depending or your requirements) scoped feature and implement your feature event handler as below: public override void FeatureActivated(SPFeatureReceiverProperties properties) { SPWeb web = GetFeatureWeb(properties); //http://karinebosch.wordpress.com/walkthroughs/event-receivers-theory/ string assemblyName =  System.Reflection.Assembly.GetExecutingAssembly().FullName; const string className = "YBBEST.AddEventReceiverToContentType.ItemContentTypeEventReceiver"; SPContentType contentType= web.ContentTypes["Item"]; AddEventReceiverToContentType(className, contentType, assemblyName, SPEventReceiverType.ItemAdded, SPEventReceiverSynchronization.Asynchronous); AddEventReceiverToContentType(className, contentType, assemblyName, SPEventReceiverType.ItemUpdated, SPEventReceiverSynchronization.Asynchronous); contentType.Update(); } protected static void AddEventReceiverToContentType(string className, SPContentType contentType, string assemblyName, SPEventReceiverType eventReceiverType, SPEventReceiverSynchronization eventReceiverSynchronization) { if (className == null) throw new ArgumentNullException("className"); if (contentType == null) throw new ArgumentNullException("contentType"); if (assemblyName == null) throw new ArgumentNullException("assemblyName"); SPEventReceiverDefinition eventReceiver = contentType.EventReceivers.Add(); eventReceiver.Synchronization = eventReceiverSynchronization; eventReceiver.Type = eventReceiverType; eventReceiver.Assembly = assemblyName; eventReceiver.Class = className; eventReceiver.Update(); } 3.Deploy your solution and now you have a event receiver that attached to the Item contentType. You can download the complete source code here.You can also check how to add event receiver to a list using SharePoint event receiver item in Visual Studio2010 in my previous blog.

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  • Mathematica Programming Language&ndash;An Introduction

    - by JoshReuben
    The Mathematica http://www.wolfram.com/mathematica/ programming model consists of a kernel computation engine (or grid of such engines) and a front-end of notebook instances that communicate with the kernel throughout a session. The programming model of Mathematica is incredibly rich & powerful – besides numeric calculations, it supports symbols (eg Pi, I, E) and control flow logic.   obviously I could use this as a simple calculator: 5 * 10 --> 50 but this language is much more than that!   for example, I could use control flow logic & setup a simple infinite loop: x=1; While [x>0, x=x,x+1] Different brackets have different purposes: square brackets for function arguments:  Cos[x] round brackets for grouping: (1+2)*3 curly brackets for lists: {1,2,3,4} The power of Mathematica (as opposed to say Matlab) is that it gives exact symbolic answers instead of a rounded numeric approximation (unless you request it):   Mathematica lets you define scoped variables (symbols): a=1; b=2; c=a+b --> 5 these variables can contain symbolic values – you can think of these as partially computed functions:   use Clear[x] or Remove[x] to zero or dereference a variable.   To compute a numerical approximation to n significant digits (default n=6), use N[x,n] or the //N prefix: Pi //N -->3.14159 N[Pi,50] --> 3.1415926535897932384626433832795028841971693993751 The kernel uses % to reference the lastcalculation result, %% the 2nd last, %%% the 3rd last etc –> clearer statements: eg instead of: Sqrt[Pi+Sqrt[Sqrt[Pi+Sqrt[Pi]]] do: Sqrt[Pi]; Sqrt[Pi+%]; Sqrt[Pi+%] The help system supports wildcards, so I can search for functions like so: ?Inv* Mathematica supports some very powerful programming constructs and a rich function library that allow you to do things that you would have to write allot of code for in a language like C++.   the Factor function – factorization: Factor[x^3 – 6*x^2 +11x – 6] --> (-3+x) (-2+x) (-1+x)   the Solve function – find the roots of an equation: Solve[x^3 – 2x + 1 == 0] -->   the Expand function – express (1+x)^10 in polynomial form: Expand[(1+x)^10] --> 1+10x+45x^2+120x^3+210x^4+252x^5+210x^6+120x^7+45x^8+10x^9+x^10 the Prime function – what is the 1000th prime? Prime[1000] -->7919 Mathematica also has some powerful graphics capabilities:   the Plot function – plot the graph of y=Sin x in a single period: Plot[Sin[x], {x,0,2*Pi}] you can also plot 3D surfaces of functions using Plot3D function

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  • Subterranean IL: Exception handling 1

    - by Simon Cooper
    Today, I'll be starting a look at the Structured Exception Handling mechanism within the CLR. Exception handling is quite a complicated business, and, as a result, the rules governing exception handling clauses in IL are quite strict; you need to be careful when writing exception clauses in IL. Exception handlers Exception handlers are specified using a .try clause within a method definition. .try <TryStartLabel> to <TryEndLabel> <HandlerType> handler <HandlerStartLabel> to <HandlerEndLabel> As an example, a basic try/catch block would be specified like so: TryBlockStart: // ... leave.s CatchBlockEndTryBlockEnd:CatchBlockStart: // at the start of a catch block, the exception thrown is on the stack callvirt instance string [mscorlib]System.Object::ToString() call void [mscorlib]System.Console::WriteLine(string) leave.s CatchBlockEnd CatchBlockEnd: // method code continues... .try TryBlockStart to TryBlockEnd catch [mscorlib]System.Exception handler CatchBlockStart to CatchBlockEnd There are four different types of handler that can be specified: catch <TypeToken> This is the standard exception catch clause; you specify the object type that you want to catch (for example, [mscorlib]System.ArgumentException). Any object can be thrown as an exception, although Microsoft recommend that only classes derived from System.Exception are thrown as exceptions. filter <FilterLabel> A filter block allows you to provide custom logic to determine if a handler block should be run. This functionality is exposed in VB, but not in C#. finally A finally block executes when the try block exits, regardless of whether an exception was thrown or not. fault This is similar to a finally block, but a fault block executes only if an exception was thrown. This is not exposed in VB or C#. You can specify multiple catch or filter handling blocks in each .try, but fault and finally handlers must have their own .try clause. We'll look into why this is in later posts. Scoped exception handlers The .try syntax is quite tricky to use; it requires multiple labels, and you've got to be careful to keep separate the different exception handling sections. However, starting from .NET 2, IL allows you to use scope blocks to specify exception handlers instead. Using this syntax, the example above can be written like so: .try { // ... leave.s EndSEH}catch [mscorlib]System.Exception { callvirt instance string [mscorlib]System.Object::ToString() call void [mscorlib]System.Console::WriteLine(string) leave.s EndSEH}EndSEH:// method code continues... As you can see, this is much easier to write (and read!) than a stand-alone .try clause. Next time, I'll be looking at some of the restrictions imposed by SEH on control flow, and how the C# compiler generated exception handling clauses.

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  • .NET Code Evolution

    - by Alois Kraus
    Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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  • Data Source Use of Oracle Edition Based Redefinition (EBR)

    - by Steve Felts
    Edition-based redefinition is a new feature in the 11gR2 release of the Oracle database. It enables you to upgrade the database component of an application while it is in use, thereby minimizing or eliminating down time. It works by allowing for a pre-upgrade and post-upgrade view of the data to exist at the same time, providing a hot upgrade capability. You can then specify which view you want for a particular session.  See the Oracle Database Advanced Application Developer's Guide for further information. There is also a good white paper at Edition Based Definition. Using this feature of the Oracle database does not require any new WebLogic Server functionality. It is set for each connection in the pool automatically by simply specifying SQL ALTER SESSION SET EDITION = edition_name in the Init SQL parameter in the data source configuration. This can be configured either via the console or via WLST (setInitSQL on the JDBCConnectionPoolParams). This SQL statement is executed for each newly created physical database connection.Note that we are assuming that a data source references only one edition of the database. To make use of this feature, you would have an earlier version of the application with a data source that references the earlier EDITION and a later version of the application with a data source that references the later EDITION.   Once you start talking about multiple versions of a WLS application, you should be using the WLS "side-by-side" or "versioned" deployment feature.  See Developing Applications for Production Redeployment for more information.  By combining Oracle database EBR and WLS versioned deployment, the application can be failed over with no downtime, making the combination of features more powerful than either independently. There is a catch - you need to be running with a versioned database and a versioned application initially so then you can switch versions.  The recommended way to version a WLS application is to simply add the "Weblogic-Application-Version" property in the MANIFEST.MF file(you can also specify it at deployment time). The recommended way to configure the data source is to use a packaged data source descriptor that's stored in the ear or war so that everything is self-contained.  There are some restrictions.  You can't use a packaged data source with Logging Last Resource (LLR) - you need to use a system resource.  You can't use an application-scoped packaged data source with EmulateTwoPhaseCommit for the global-transactions-protocol with a versioned application - use a global scope.  See Configuring JDBC Application Modules for Deployment for more details. There's one known problem - it doesn't work correctly with an XA data source (patch available with bug 14075837).

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  • Load NSImage into QPixmap or QImage

    - by Thomi
    I have an NSImage pointer from a platform SDK, and I need to load it into Qt's QImage class. To make things easier, I can create a QImage from a CGImageRef by using QPixmap as an intermediate format, like this: CGImageRef myImage = // ... get a CGImageRef somehow. QImage img = QPixmap::fromMacCGImageRef(myImage).toImage(); However, I cannot find a way to convert from an NSImage to a CGImageRef. Several other people have had the same problem, but I have yet to find a solution. There is the CGImageForProposedRect method, but I can't seem to get it to work. I'm currently trying this (img is my NSImage ptr): CGImageRef ir = [img CGImageFirProposedRect:0:0:0]; Any ideas?

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  • Nested class or not nested class?

    - by eriks
    I have class A and list of A objects. A has a function f that should be executed every X seconds (for the first instance every 1 second, for the seconds instance every 5 seconds, etc.). I have a scheduler class that is responsible to execute the functions at the correct time. What i thought to do is to create a new class, ATime, that will hold ptr to A instance and the time A::f should be executed. The scheduler will hold a min priority queue of Atime. Do you think it is the correct implementation? Should ATime be a nested class of the scheduler?

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  • Is it possible to sendkeys / Post Message directly to a HtmlElement rather than to a C# webbrowser

    - by Jakub
    I would like to send keys to a c# web browser control element directly, not just the window with the correct focus. Right now I am able to send a key using PostMessage and documentHandle and focus like this i.e. Pseudo Code HtmlElement el = getelement(); el.Focus(); IntPtr docptr = browser.Handle; PostMessage(docptr,WM_KEYDOWN,1,0); .... KEYCHAR, KEYUP.. I was wondering if anyone knows of any way to be able to do this in a background, so that the focus is not on the element. Basically is there a way to get a IntPtr to the HtmlElement itself, than use that instead in the PostMessage or SendKeys API rather than the browser handle/ptr.

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  • error A2070: invalid instruction operands IN SSE MASM64

    - by Green
    when compiling this in ml64.exe 64bit (masm64) the SSE command give me an error what do i need to do to include the SSE commands in 64 bit? .code test PROC movlps [rdx], xmm7 ;;error A2070: invalid instruction operands ;//Inc in vec ptr add rsi, 16 movhlps xmm6, xmm7 movss [rdx+8], xmm6 ;;rror A2070: invalid instruction operands ret test ENDP end i get the error: 1>Performing Custom Build Step 1> Assembling: extasm.asm 1>extasm.asm(6) : error A2070: invalid instruction operands 1>extasm.asm(10) : error A2070: invalid instruction operands 1>Microsoft (R) Macro Assembler (x64) Version 8.00.50727.215 1>Copyright (C) Microsoft Corporation. All rights reserved. 1>Project : error PRJ0019: A tool returned an error code from "Performing Custom Build Step"

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  • Address of function is not actual code address

    - by mrjoltcola
    Debugging some code in Visual Studio 2008 (C++), I noticed that the address in my function pointer variable is not the actual address of the function itself. This is an extern "C" function. int main() { void (*printaddr)(const char *) = &print; // debug shows printaddr == 0x013C1429 } Address: 0x013C4F10 void print() { ... } The disassembly of taking the function address is: void (*printaddr)(const char *) = &print; 013C7465 C7 45 BC 29 14 3C 01 mov dword ptr [printaddr],offset print (13C1429h) What am I missing?

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  • Erasing and modifying elements in Boost MultiIndex Container

    - by Sarah
    I'm trying to use a Boost MultiIndex container in my simulation. My knowledge of C++ syntax is very weak, and I'm concerned I'm not properly removing an element from the container or deleting it from memory. I also need to modify elements, and I was hoping to confirm the syntax and basic philosophy here too. // main.cpp ... #include <boost/multi_index_container.hpp> #include <boost/multi_index/hashed_index.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/mem_fun.hpp> #include <boost/tokenizer.hpp> #include <boost/shared_ptr.hpp> ... #include "Host.h" // class Host, all members private, using get fxns to access using boost::multi_index_container; using namespace boost::multi_index; typedef multi_index_container< boost::shared_ptr< Host >, indexed_by< hashed_unique< const_mem_fun<Host,int,&Host::getID> > // ordered_non_unique< BOOST_MULTI_INDEX_MEM_FUN(Host,int,&Host::getAge) > > // end indexed_by > HostContainer; typedef HostContainer::nth_index<0>::type HostsByID; int main() { ... HostContainer allHosts; Host * newHostPtr; newHostPtr = new Host( t, DOB, idCtr, 0, currentEvents ); allHosts.insert( boost::shared_ptr<Host>(newHostPtr) ); // allHosts gets filled up int randomHostID = 4; int newAge = 50; modifyHost( randomHostID, allHosts, newAge ); killHost( randomHostID, allHosts ); } void killHost( int id, HostContainer & hmap ){ HostsByID::iterator it = hmap.find( id ); cout << "Found host id " << (*it)->getID() << "Attempting to kill. hmap.size() before is " << hmap.size() << " and "; hmap.erase( it ); // Is this really erasing (freeing from mem) the underlying Host object? cout << hmap.size() << " after." << endl; } void modifyHost( int id, HostContainer & hmap, int newAge ){ HostsByID::iterator it = hmap.find( id ); (*it) -> setAge( newAge ); // Not actually the "modify" function for MultiIndex... } My questions are In the MultiIndex container allHosts of shared_ptrs to Host objects, is calling allHosts.erase( it ) on an iterator to the object's shared_ptr enough to delete the object permanently and free it from memory? It appears to be removing the shared_ptr from the container. The allhosts container currently has one functioning index that relies on the host's ID. If I introduce an ordered second index that calls on a member function (Host::getAge()), where the age changes over the course of the simulation, is the index always going to be updated when I refer to it? What is the difference between using the MultiIndex's modify to modify the age of the underlying object versus the approach I show above? I'm vaguely confused about what is assumed/required to be constant in MultiIndex. Thanks in advance. Update Here's my attempt to get the modify syntax working, based on what I see in a related Boost example. struct update_age { update_age():(){} // have no idea what this really does... elicits error void operator() (boost::shared_ptr<Host> ptr) { ptr->incrementAge(); // incrementAge() is a member function of class Host } }; and then in modifyHost, I'd have hmap.modify(it,update_age). Even if by some miracle this turns out to be right, I'd love some kind of explanation of what's going on.

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  • Is this a good code (came across while reading code of a colleague)

    - by eriks
    // file a.hpp class a; typedef boost::shared_ptr<a> aPtr class a{ public: static aPtr CreateImp(); virtual void Foo() = 0 ; .... }; //file aImp.hpp class aImp : public a{ virtual void Foo(); }; //file aImp.cpp aPtr a::CreateImp() { return aPtr(new aImp()); } void aImp::Foo(){} The client must use CreateImp to get ptr to 'a', and can't use 'a' other ways. What do you think about this implementation? what do you think about this king of implementation?

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  • Exchange 2010 Hub cannot deliver to Exchange 2007 Hub - "451 5.7.3 Cannot achieve Exchange Server authentication"

    - by Graeme Donaldson
    We have an existing Exchange 2007 server in Site A (exch07). I've installed an Exchange 2010 server in Site B (exch10). Both servers have the CAS, Mailbox and Hub roles. Messages sent via SMTP on exch10 which are destined for mailboxes on exch07 are queued with the "Last Error" reported in Queue Viewer as '451 4.4.0 Primary target IP address responded with: "451 5.7.3 Cannot achieve Exchange Server authentication." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts.' I've found that some people have resolved this by creating new Receive Connectors which are scoped specifically to apply to connections from the remote hub/s, but I have had no luck doing this. Specifically I created new receive connectors on both servers with the following settings: Remote IP = IP/s of remote server Authentication = "Transport Layer Security (TLS)" and "Exchange Server authentication" Permission Groups = "Exchange servers" and "Legacy Exchange Servers" This made no difference, I see the same error message. What am I missing? Update: We noticed that the Application log had this error message from MSExchangeTransportService: Microsoft Exchange could not find a certificate that contains the domain name exch07.domain.local in the personal store on the local computer. Therefore, it is unable to support the STARTTLS SMTP verb for the connector exch10 with a FQDN parameter of exch07.domain.local. If the connector's FQDN is not specified, the computer's FQDN is used. Verify the connector configuration and the installed certificates to make sure that there is a certificate with a domain name for that FQDN. If this certificate exists, run Enable-ExchangeCertificate -Services SMTP to make sure that the Microsoft Exchange Transport service has access to the certificate key. It turns out that the default self-signed certificate was no longer enabled for the SMTP service for some reason. After enabling the self-signed certificate for SMTP, we no longer get the error in the event logs, but delivery is still failing with the same error message. Update 2: I put a mailbox on exch10 and attempted to deliver a message via SMTP on exch07 and I get the same error.

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  • can these be made unambiguous

    - by R Samuel Klatchko
    I'm trying to create a set of overloaded templates for arrays/pointers where one template will be used when the compiler knows the size of the array and the other template will be used when it doesn't: template <typename T, size_t SZ> void moo(T (&arr)[SZ]) { ... } template <typename T> void moo(T *ptr) { ... } The problem is that when the compiler knows the size of the array, the overloads are ambiguous and the compile fails. Is there some way to resolve the ambiguity (perhaps via SFINAE) or is this just not possible.

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  • Gmail rejects emails. Openspf.net fails the tests

    - by pablomedok
    I've got a problem with Gmail. It started after one of our trojan infected PCs sent spam for one day from our IP address. We've fixed the problem, but we got into 3 black lists. We've fixed that, too. But still every time we send an email to Gmail the message is rejected: So I've checked Google Bulk Sender's guide once again and found an error in our SPF record and fixed it. Google says everything should become fine after some time, but this doesn't happen. 3 weeks already passed but we still can't send emails to Gmail. Our MX setup is a bit complex, but not too much: We have a domain name delo-company.com, it has it's own mail @delo-company.com (this one is fine, but the problems are with sub-domain name corp.delo-company.com). Delo-company.com domain has several DNS records for the subdomain: corp A 82.209.198.147 corp MX 20 corp.delo-company.com corp.delo-company.com TXT "v=spf1 ip4:82.209.198.147 ~all" (I set ~all for testing purposes only, it was -all before that) These records are for our corporate Exchange 2003 server at 82.209.198.147. Its LAN name is s2.corp.delo-company.com so its HELO/EHLO greetings are also s2.corp.delo-company.com. To pass EHLO check we've also created some records in delo-company.com's DNS: s2.corp A 82.209.198.147 s2.corp.delo-company.com TXT "v=spf1 ip4:82.209.198.147 ~all" As I understand SPF verifications should be passed in this way: Out server s2 connects to MX of the recepient (Rcp.MX): EHLO s2.corp.delo-company.com Rcp.MX says Ok, and makes SPF check of HELO/EHLO. It does NSlookup for s2.corp.delo-company.com and gets the above DNS-records. TXT records says that s2.corp.delo-company.com should be only from IP 82.209.198.147. So it should be passed. Then our s2 server says RCPT FROM: Rcp.MX` server checks it, too. The values are the same so they should also be positive. Maybe there is also a rDNS check, but I'm not sure what is checked HELO or RCPT FROM. Our PTR record for 82.209.198.147 is: 147.198.209.82.in-addr.arpa. 86400 IN PTR s2.corp.delo-company.com. To me everything looks fine, but anyway all emails are rejected by Gmail. So, I've checked MXtoolbox.com - it says everything is fine, I passed http://www.kitterman.com/spf/validate.html Python check, I did 25port.com email test. It's fine, too: Return-Path: <[email protected]> Received: from s2.corp.delo-company.com (82.209.198.147) by verifier.port25.com id ha45na11u9cs for <[email protected]>; Fri, 2 Mar 2012 13:03:21 -0500 (envelope-from <[email protected]>) Authentication-Results: verifier.port25.com; spf=pass [email protected] Authentication-Results: verifier.port25.com; domainkeys=neutral (message not signed) [email protected] Authentication-Results: verifier.port25.com; dkim=neutral (message not signed) Authentication-Results: verifier.port25.com; sender-id=pass [email protected] Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01CCF89E.BE02A069" Subject: test Date: Fri, 2 Mar 2012 21:03:15 +0300 X-MimeOLE: Produced By Microsoft Exchange V6.5 Message-ID: <[email protected]> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: test Thread-Index: Acz4jS34oznvbyFQR4S5rXsNQFvTdg== From: =?koi8-r?B?89XQ0tXOwMsg8MHXxcw=?= <[email protected]> To: <[email protected]> I also checked with [email protected], but it FAILs all the time, no matter which SPF records I make: <s2.corp.delo-company.com #5.7.1 smtp;550 5.7.1 <[email protected]>: Recipient address rejected: SPF Tests: Mail-From Result="softfail": Mail From="[email protected]" HELO name="s2.corp.delo-company.com" HELO Result="softfail" Remote IP="82.209.198.147"> I've filled Gmail form twice, but nothing happens. We do not send spam, only emails for our clients. 2 or 3 times we did mass emails (like New Year Greetings and sales promos) from corp.delo-company.com addresses, but they where all complying to Gmail Bulk Sender's Guide (I mean SPF, Open Relays, Precedence: Bulk and Unsubscribe tags). So, this should be not a problem. Please, help me. What am I doing wrong? UPD: I also tried Unlocktheinbox.com test and the server also fails this test. Here is the result: http://bit.ly/wYr39h . Here is one more http://bit.ly/ypWLjr I also tried to send email from that server manually via telnet and everything is fine. Here is what I type: 220 mx.google.com ESMTP g15si4811326anb.170 HELO s2.corp.delo-company.com 250 mx.google.com at your service MAIL FROM: <[email protected]> 250 2.1.0 OK g15si4811326anb.170 RCPT TO: <[email protected]> 250 2.1.5 OK g15si4811326anb.170 DATA 354 Go ahead g15si4811326anb.170 From: [email protected] To: Pavel <[email protected]> Subject: Test 28 This is telnet test . 250 2.0.0 OK 1330795021 g15si4811326anb.170 QUIT 221 2.0.0 closing connection g15si4811326anb.170 And this is what I get: Delivered-To: [email protected] Received: by 10.227.132.73 with SMTP id a9csp96864wbt; Sat, 3 Mar 2012 09:17:02 -0800 (PST) Received: by 10.101.128.12 with SMTP id f12mr4837125ann.49.1330795021572; Sat, 03 Mar 2012 09:17:01 -0800 (PST) Return-Path: <[email protected]> Received: from s2.corp.delo-company.com (s2.corp.delo-company.com. [82.209.198.147]) by mx.google.com with SMTP id g15si4811326anb.170.2012.03.03.09.15.59; Sat, 03 Mar 2012 09:17:00 -0800 (PST) Received-SPF: pass (google.com: domain of [email protected] designates 82.209.198.147 as permitted sender) client-ip=82.209.198.147; Authentication-Results: mx.google.com; spf=pass (google.com: domain of [email protected] designates 82.209.198.147 as permitted sender) [email protected] Date: Sat, 03 Mar 2012 09:17:00 -0800 (PST) Message-Id: <[email protected]> From: [email protected] To: Pavel <[email protected]> Subject: Test 28 This is telnet test

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  • Accorian menu is not working properly

    - by Zerotoinfinite
    Hi, I am using accordin menu in my site, placed in Master Page, It has 4 pane, each pane have multiple links. it was working fine previously. But suddenly it is displaying this error message There is no source code available for the current location. It's is asking for show assembly. When I clicked on that I got a stopage at the stack 0000001a mov eax,dword ptr [ebp-0Ch] -- I am really not sure what does it means. Also, there are several links in accordin menu, after clicking on anyone of the link I am not able to click the other link, might be because of the above reason. Please help

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  • What does: throw 0 do/mean? Is it "bad"?

    - by MartinP
    Context I came across some code, like this: if( Some_Condition ) throw 0; I googled a bit, and found a few other code snippets using that odd looking throw 0 form. I presume one would catch this as: catch(const int& e) { } Or is this a NULL ptr? to be caught as void* ? Question What does this throw 0 do? Is it special in some way? My normal preference would be to throw something that is (or derived from) std::exception. So to me this looks "bad". Is it "bad" ?

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  • Virtual Function Implementation

    - by Gokul
    Hi, I have kept hearing this statement. Switch..Case is Evil for code maintenance, but it provides better performance(since compiler can inline stuffs etc..). Virtual functions are very good for code maintenance, but they incur a performance penalty of two pointer indirections. Say i have a base class with 2 subclasses(X and Y) and one virtual function, so there will be two virtual tables. The object has a pointer, based on which it will choose a virtual table. So for the compiler, it is more like switch( object's function ptr ) { case 0x....: X->call(); break; case 0x....: Y->call(); }; So why should virtual function cost more, if it can get implemented this way, as the compiler can do the same in-lining and other stuff here. Or explain me, why is it decided not to implement the virtual function execution in this way? Thanks, Gokul.

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  • Is it safe to catch an access violation in this scenario?

    - by Eloff
    I've read a lot, including here on SO that suggests this is a very bad idea in general and that the only thing you can do safely is exit the program. I'm not sure that this is true. This is for a pooling memory allocator that hands off large allocations to malloc. During pool_free() a pointer needs to be checked it it belongs to a pool or was allocated with malloc. By rounding the address down to the nearest 1MB boundary, I get a pointer to the beginning of a block of memory in the pool, or undefined if malloc was used. In the first case I can easily verify that the block of memory belongs to the pool, but, if it does not I will either fail this verification, or I will get an access violation (note that this is a read-only process). Could I not catch this with SEH (Windows) or handle the signal (POSIX) and simply treat it as a failed verification? (i.e. this is only possible if malloc was used, so pass the ptr to free())

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  • can these templates be made unambiguous

    - by R Samuel Klatchko
    I'm trying to create a set of overloaded templates for arrays/pointers where one template will be used when the compiler knows the size of the array and the other template will be used when it doesn't: template <typename T, size_t SZ> void moo(T (&arr)[SZ]) { ... } template <typename T> void moo(T *ptr) { ... } The problem is that when the compiler knows the size of the array, the overloads are ambiguous and the compile fails. Is there some way to resolve the ambiguity (perhaps via SFINAE) or is this just not possible.

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  • Reference to a pointer question

    - by Yogesh Arora
    Please refer to the code below. In this code i am storing the const char* returned by test.c_str() into a reference. My question is Will the data be correctly refering to the contents of test. I am thinking that ptr returned by test.c_str() will be a temporary and if i bound it to a reference that reference will not be valid. Is my thinking correct class RefPtrTest { std::string test; StoringClass storingClass; public: RefPtrTest(): test("hello"), storingClass(test.c_str()) { } } where StoringClass is class StoringClass { const char*& data; public: StoringClass (const char*& input): data(input) { } }

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  • Custom Memory Allocator for STL map

    - by Prasoon Tiwari
    This question is about construction of instances of custom allocator during insertion into a std::map. Here is a custom allocator for std::map<int,int> along with a small program that uses it: #include <stddef.h> #include <stdio.h> #include <map> #include <typeinfo> class MyPool { public: void * GetNext() { return malloc(24); } void Free(void *ptr) { free(ptr); } }; template<typename T> class MyPoolAlloc { public: static MyPool *pMyPool; typedef size_t size_type; typedef ptrdiff_t difference_type; typedef T* pointer; typedef const T* const_pointer; typedef T& reference; typedef const T& const_reference; typedef T value_type; template<typename X> struct rebind { typedef MyPoolAlloc<X> other; }; MyPoolAlloc() throw() { printf("-------Alloc--CONSTRUCTOR--------%08x %32s\n", this, typeid(T).name()); } MyPoolAlloc(const MyPoolAlloc&) throw() { printf(" Copy Constructor ---------------%08x %32s\n", this, typeid(T).name()); } template<typename X> MyPoolAlloc(const MyPoolAlloc<X>&) throw() { printf(" Construct T Alloc from X Alloc--%08x %32s %32s\n", this, typeid(T).name(), typeid(X).name()); } ~MyPoolAlloc() throw() { printf(" Destructor ---------------------%08x %32s\n", this, typeid(T).name()); }; pointer address(reference __x) const { return &__x; } const_pointer address(const_reference __x) const { return &__x; } pointer allocate(size_type __n, const void * hint = 0) { if (__n != 1) perror("MyPoolAlloc::allocate: __n is not 1.\n"); if (NULL == pMyPool) { pMyPool = new MyPool(); printf("======>Creating a new pool object.\n"); } return reinterpret_cast<T*>(pMyPool->GetNext()); } //__p is not permitted to be a null pointer void deallocate(pointer __p, size_type __n) { pMyPool->Free(reinterpret_cast<void *>(__p)); } size_type max_size() const throw() { return size_t(-1) / sizeof(T); } void construct(pointer __p, const T& __val) { printf("+++++++ %08x %s.\n", __p, typeid(T).name()); ::new(__p) T(__val); } void destroy(pointer __p) { printf("-+-+-+- %08x.\n", __p); __p->~T(); } }; template<typename T> inline bool operator==(const MyPoolAlloc<T>&, const MyPoolAlloc<T>&) { return true; } template<typename T> inline bool operator!=(const MyPoolAlloc<T>&, const MyPoolAlloc<T>&) { return false; } template<typename T> MyPool* MyPoolAlloc<T>::pMyPool = NULL; int main(int argc, char *argv[]) { std::map<int, int, std::less<int>, MyPoolAlloc<std::pair<const int,int> > > m; //random insertions in the map m.insert(std::pair<int,int>(1,2)); m[5] = 7; m[8] = 11; printf("======>End of map insertions.\n"); return 0; } Here is the output of this program: -------Alloc--CONSTRUCTOR--------bffcdaa6 St4pairIKiiE Construct T Alloc from X Alloc--bffcda77 St13_Rb_tree_nodeISt4pairIKiiEE St4pairIKiiE Copy Constructor ---------------bffcdad8 St13_Rb_tree_nodeISt4pairIKiiEE Destructor ---------------------bffcda77 St13_Rb_tree_nodeISt4pairIKiiEE Destructor ---------------------bffcdaa6 St4pairIKiiE ======Creating a new pool object. Construct T Alloc from X Alloc--bffcd9df St4pairIKiiE St13_Rb_tree_nodeISt4pairIKiiEE +++++++ 0985d028 St4pairIKiiE. Destructor ---------------------bffcd9df St4pairIKiiE Construct T Alloc from X Alloc--bffcd95f St4pairIKiiE St13_Rb_tree_nodeISt4pairIKiiEE +++++++ 0985d048 St4pairIKiiE. Destructor ---------------------bffcd95f St4pairIKiiE Construct T Alloc from X Alloc--bffcd95f St4pairIKiiE St13_Rb_tree_nodeISt4pairIKiiEE +++++++ 0985d068 St4pairIKiiE. Destructor ---------------------bffcd95f St4pairIKiiE ======End of map insertions. Construct T Alloc from X Alloc--bffcda23 St4pairIKiiE St13_Rb_tree_nodeISt4pairIKiiEE -+-+-+- 0985d068. Destructor ---------------------bffcda23 St4pairIKiiE Construct T Alloc from X Alloc--bffcda43 St4pairIKiiE St13_Rb_tree_nodeISt4pairIKiiEE -+-+-+- 0985d048. Destructor ---------------------bffcda43 St4pairIKiiE Construct T Alloc from X Alloc--bffcda43 St4pairIKiiE St13_Rb_tree_nodeISt4pairIKiiEE -+-+-+- 0985d028. Destructor ---------------------bffcda43 St4pairIKiiE Destructor ---------------------bffcdad8 St13_Rb_tree_nodeISt4pairIKiiEE Last two columns of the output show that an allocator for std::pair<const int, int> is constructed everytime there is a insertion into the map. Why is this necessary? Is there a way to suppress this? Thanks! Edit: This code tested on x86 machine with g++ version 4.1.2. If you wish to run it on a 64-bit machine, you'll have to change at least the line return malloc(24). Changing to return malloc(48) should work.

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