Search Results

Search found 6638 results on 266 pages for 'boost range'.

Page 66/266 | < Previous Page | 62 63 64 65 66 67 68 69 70 71 72 73  | Next Page >

• ld: symbol(s) not found with OpenSSL (libssl)

  - by Benjamin

  Hi all, I'm trying to build TorTunnel on my mac. I've successfully installed the Boost library and its development files. TorTunnel also requires the OpenSSL and its development files. I've got them installed in /usr/lib/libssl.dylib and /usr/include/openssl/. When I run the make command this is the error i'm getting: g++ -ggdb -g -O2 -lssl -lboost_system-xgcc42-mt-1_38 -o torproxy TorProxy.o HybridEncryption.o Connection.o Cell.o Directory.o ServerListing.o Util.o Circuit.o CellEncrypter.o RelayCellDispatcher.o CellConsumer.o ProxyShuffler.o CreateCell.o CreatedCell.o TorTunnel.o SocksConnection.o Network.o Undefined symbols: "_BN_hex2bn", referenced from: Circuit::initializeDhParameters() in Circuit.o "_BN_free", referenced from: Circuit::~Circuit()in Circuit.o Circuit::~Circuit()in Circuit.o CreatedCell::getKeyMaterial(unsigned char**, unsigned char**)in CreatedCell.o "_DH_generate_key", referenced from: Circuit::initializeDhParameters() in Circuit.o "_PEM_read_bio_RSAPublicKey", referenced from: ServerListing::getOnionKey() in ServerListing.o "_BIO_s_mem", referenced from: Connection::initializeSSL() in Connection.o Connection::initializeSSL() in Connection.o "_DH_free", referenced from: Circuit::~Circuit()in Circuit.o "_BIO_ctrl_pending", referenced from: Connection::writeFromBuffer(boost::function)in Connection.o "_RSA_size", referenced from: HybridEncryption::encryptInSingleChunk(unsigned char*, int, unsigned char**, int*, rsa_st*)in HybridEncryption.o HybridEncryption::encryptInHybridChunk(unsigned char*, int, unsigned char**, int*, rsa_st*)in HybridEncryption.o HybridEncryption::encrypt(unsigned char*, int, unsigned char**, int*, rsa_st*)in HybridEncryption.o "_RSA_public_encrypt", referenced from: HybridEncryption::encryptInSingleChunk(unsigned char*, int, unsigned char**, int*, rsa_st*)in HybridEncryption.o HybridEncryption::encryptInHybridChunk(unsigned char*, int, unsigned char**, int*, rsa_st*)in HybridEncryption.o "_BN_num_bits", referenced from: CreateCell::CreateCell(unsigned short, dh_st*, rsa_st*)in CreateCell.o CreatedCell::getKeyMaterial(unsigned char**, unsigned char**)in CreatedCell.o CreatedCell::getKeyMaterial(unsigned char**, unsigned char**)in CreatedCell.o CreatedCell::isValid() in CreatedCell.o "_SHA1", referenced from: CellEncrypter::expandKeyMaterial(unsigned char*, int, unsigned char*, int)in CellEncrypter.o "_BN_bn2bin", referenced from: CreateCell::CreateCell(unsigned short, dh_st*, rsa_st*)in CreateCell.o "_BN_bin2bn", referenced from: CreatedCell::getKeyMaterial(unsigned char**, unsigned char**)in CreatedCell.o "_DH_compute_key", referenced from: CreatedCell::getKeyMaterial(unsigned char**, unsigned char**)in CreatedCell.o "_BIO_new", referenced from: Connection::initializeSSL() in Connection.o Connection::initializeSSL() in Connection.o "_BIO_new_mem_buf", referenced from: ServerListing::getOnionKey() in ServerListing.o "_AES_ctr128_encrypt", referenced from: HybridEncryption::AES_encrypt(unsigned char*, int, unsigned char*, unsigned char*, int)in HybridEncryption.o CellEncrypter::aesOperate(Cell&, aes_key_st*, unsigned char*, unsigned char*, unsigned int*)in CellEncrypter.o "_BIO_read", referenced from: Connection::writeFromBuffer(boost::function)in Connection.o "_SHA1_Update", referenced from: CellEncrypter::calculateDigest(SHAstate_st*, RelayCell&, unsigned char*)in CellEncrypter.o CellEncrypter::initKeyMaterial(unsigned char*)in CellEncrypter.o CellEncrypter::initKeyMaterial(unsigned char*)in CellEncrypter.o "_SHA1_Final", referenced from: CellEncrypter::calculateDigest(SHAstate_st*, RelayCell&, unsigned char*)in CellEncrypter.o "_DH_size", referenced from: CreatedCell::getKeyMaterial(unsigned char**, unsigned char**)in CreatedCell.o "_DH_new", referenced from: Circuit::initializeDhParameters() in Circuit.o "_BIO_write", referenced from: Connection::readIntoBufferComplete(boost::function, boost::system::error_code const&, unsigned long)in Connection.o "_RSA_free", referenced from: Circuit::~Circuit()in Circuit.o "_BN_dup", referenced from: Circuit::initializeDhParameters() in Circuit.o Circuit::initializeDhParameters() in Circuit.o "_BN_new", referenced from: Circuit::initializeDhParameters() in Circuit.o Circuit::initializeDhParameters() in Circuit.o "_SHA1_Init", referenced from: CellEncrypter::CellEncrypter()in CellEncrypter.o CellEncrypter::CellEncrypter()in CellEncrypter.o "_RAND_bytes", referenced from: HybridEncryption::encryptInHybridChunk(unsigned char*, int, unsigned char**, int*, rsa_st*)in HybridEncryption.o Util::getRandomId() in Util.o "_AES_set_encrypt_key", referenced from: HybridEncryption::AES_encrypt(unsigned char*, int, unsigned char*, unsigned char*, int)in HybridEncryption.o CellEncrypter::initKeyMaterial(unsigned char*)in CellEncrypter.o CellEncrypter::initKeyMaterial(unsigned char*)in CellEncrypter.o "_BN_set_word", referenced from: Circuit::initializeDhParameters() in Circuit.o "_RSA_new", referenced from: ServerListing::getOnionKey() in ServerListing.o ld: symbol(s) not found collect2: ld returned 1 exit status make: *** [torproxy] Error 1 Any idea how I could fix it?

  Read the article

• Who does non-decimal bignums with floating radix point?

  - by boost

  Nice as the Tcl libraries math::bignum and math::bigfloat are, the middle ground between the two needs to be addressed. Namely, bignums which are in different radices and have a radix point. At present math::bignum only handles integers (afaict) and math::bigfloat won't let you specify different radices to math::bigfloat::fromstr (ditto). Does anyone know of a library, for any of the major scripting languages (e.g. Tcl, Perl, Python, Ruby, Lua) or less major ones (newLISP for example), which implements bignums in different radices with handling for radix point?

  Read the article

• What development tools support creation of Windows Services?

  - by boost

  Aside from ActiveState's PerlSvc, what other interpreters and compilers support the development of Windows Services?

  Read the article

• How do you change the subdocument location in a Word 2007 master document programmatically?

  - by boost

  We have had the unenviable happen: various master documents refer to sub-documents that are no longer where they used to be due to a directory renaming. Is there a programmatic way of tweaking the HYPERLINK field without losing the master/sub-document relationship? I've got this far ... Sub FixyaLinks() Dim s 'As String Dim i As Long Dim bTrackRevFlag As Boolean Dim bShowRevFlag As Boolean bTrackRevFlag = ActiveDocument.TrackRevisions bShowRevFlag = ActiveDocument.ShowRevisions ActiveDocument.TrackRevisions = False ActiveDocument.ShowRevisions = False For i = 1 To ActiveDocument.Fields.Count s = ActiveDocument.Fields.Item(i).Code.Text If InStr(s, "CURRICULUM\\NEW") Then s = Replace(s, "NEW Foundation Units-in developing", "Foundation Programme Units") ActiveDocument.Fields.Item(i).Code.Text = s End If Next ActiveDocument.TrackRevisions = bTrackRevFlag ActiveDocument.ShowRevisions = bShowRevFlag End Sub It bombs on ActiveDocument.Fields.Item(i).Code.Text = s, with an error 5686 ("The operation cannot be completed because the Track Changes option in the master document does not match the option the the subdocument. Make the Track Changes option the same in the master document and subdocument.") However, I'm not entirely sure what that means. Ideas anyone?

  Read the article

• Runtime analysis

  - by Joe Smith

  can someone please help me with the analysis of the following function (for inputs of size n). The part that confuses me the most is the inner for loop. def prefix_sums(L): # Total cost = ? pSum = [] #cost = 1 for a in range(len(L)+1): # range + body of function = (n+1) + (n+1)*(body) ? s = 0 #cost = 1 for b in range(a): # cost = ? s = s + L[b] #cost = operation + accessing list = 2 pSum.append(s) #cost = 1 return pSum #cost = 1 What I need to do is figure out the cost of each statement.

  Read the article

• What is wrong with this recursive Windows CMD script? It won't do Ackermann properly

  - by boost

  I've got this code that I'm trying to get to calculate the Ackermann function so that I can post it up on RosettaCode. It almost works. I thought maybe there'd be a few batch file wizards on StackOverflow. ::echo off set depth=0 :ack if %1==0 goto m0 if %2==0 goto n0 :else set /a n=%2-1 set /a depth+=1 call :ack %1 %n% set t=%errorlevel% set /a depth-=1 set /a m=%1-1 set /a depth+=1 call :ack %m% %t% set t=%errorlevel% set /a depth-=1 if %depth%==0 ( exit %t% ) else ( exit /b %t% ) :m0 set/a n=%2+1 if %depth%==0 ( exit %n% ) else ( exit /b %n% ) :n0 set /a m=%1-1 set /a depth+=1 call :ack %m% %2 set t=%errorlevel% set /a depth-=1 if %depth%==0 ( exit %t% ) else ( exit /b %t% ) I use this script to test it @echo off cmd/c ackermann.cmd %1 %2 echo Ackermann of %1 %2 is %errorlevel% A sample output, for Test 1 1, gives: >test 1 1 >set depth=0 >if 1 == 0 goto m0 >if 1 == 0 goto n0 >set /a n=1-1 >set /a depth+=1 >call :ack 1 0 >if 1 == 0 goto m0 >if 0 == 0 goto n0 >set /a m=1-1 >set /a depth+=1 >call :ack 0 0 >if 0 == 0 goto m0 >set/a n=0+1 >if 2 == 0 (exit 1 ) else (exit /b 1 ) >set t=1 >set /a depth-=1 >if 1 == 0 (exit 1 ) else (exit /b 1 ) >set t=1 >set /a depth-=1 >set /a m=1-1 >set /a depth+=1 >call :ack 0 1 >if 0 == 0 goto m0 >set/a n=1+1 >if 1 == 0 (exit 2 ) else (exit /b 2 ) >set t=2 >set /a depth-=1 >if 0 == 0 (exit 2 ) else (exit /b 2 ) Ackermann of 1 1 is 2

  Read the article

• What tasks aren't easy for PHP, ColdFusion and ASP?

  - by boost

  PHP, ColdFusion, and ASP (among many others) are usually sold on their strengths. What are their weaknesses? If one were to develop a niche product to handle the things that these products weren't so good at, what should it focus on? EDIT I'm trying to figure out what things PHP etc are bad at. They're all good at doing the nuts and bolts stuff, if one is looking with a bottom-to-top mindset. I'm thinking a little more globally, more top-to-bottom; what's difficult to achieve in PHP/ASP/CF without thousands of lines of code and twenty minutes of server time? EDIT Suppose company A comes up to you and says, "We want you to do x in PHP." What values of x will cause you to say, "Forget it, buddy, no one in their right mind would use PHP for that"? (swap PHP in the above quote for your favourite tool) EDIT Have we got to the point where everyone's needs can be met with PHP frameworks, Rails and ... er ... Java?

  Read the article

• What tasks aren't easy for PHP, Cold Fusion and ASP?

  - by boost

  PHP, Cold Fusion, and ASP (among many others) are usually sold on their strengths. What are their weaknesses? If one were to develop a niche product to handle the things that these products weren't so good at, what should it focus on?

  Read the article

• Where can I find a demonstration of a buffer overflow?

  - by boost

  Is there a site, or is there a simple way of setting up one, which demonstrates what can happen with a buffer overrun? This is in the context of a web app.

  Read the article

• How do you calculate div and mod of floating point numbers?

  - by boost

  In Perl, the % operator seems to assume integers. For instance: sub foo { my $n1 = shift; my $n2 = shift; print "perl's mod=" . $n1 % $n2, "\n"; my $res = $n1 / $n2; my $t = int($res); print "my div=$t", "\n"; $res = $res - $t; $res = $res * $n2; print "my mod=" . $res . "\n\n"; } foo( 3044.952963, 7.1 ); foo( 3044.952963, -7.1 ); foo( -3044.952963, 7.1 ); foo( -3044.952963, -7.1 ); gives perl's mod=6 my div=428 my mod=6.15296300000033 perl's mod=-1 my div=-428 my mod=6.15296300000033 perl's mod=1 my div=-428 my mod=-6.15296300000033 perl's mod=-6 my div=428 my mod=-6.15296300000033 Now as you can see, I've come up with a "solution" already for calculating div and mod. However, what I don't understand is what effect the sign of each argument should have on the result. Wouldn't the div always be positive, being the number of times n2 fits into n1? How's the arithmetic supposed to work in this situation?

  Read the article

• Why is modulus different in different programming languages?

  - by boost

  Perl print 2 % -18; -- -16 Tcl puts [expr {2 % -18}] -- -16 but VBScript wscript.echo 2 mod -18 -- 2 Why the difference?

  Read the article

• Exploring TCP throughput with DTrace (2)

  - by user12820842

  Last time, I described how we can use the overlap in distributions of unacknowledged byte counts and send window to determine whether the peer's receive window may be too small, limiting throughput. Let's combine that comparison with a comparison of congestion window and slow start threshold, all on a per-port/per-client basis. This will help us Identify whether the congestion window or the receive window are limiting factors on throughput by comparing the distributions of congestion window and send window values to the distribution of outstanding (unacked) bytes. This will allow us to get a visual sense for how often we are thwarted in our attempts to fill the pipe due to congestion control versus the peer not being able to receive any more data. Identify whether slow start or congestion avoidance predominate by comparing the overlap in the congestion window and slow start distributions. If the slow start threshold distribution overlaps with the congestion window, we know that we have switched between slow start and congestion avoidance, possibly multiple times. Identify whether the peer's receive window is too small by comparing the distribution of outstanding unacked bytes with the send window distribution (i.e. the peer's receive window). I discussed this here. # dtrace -s tcp_window.d dtrace: script 'tcp_window.d' matched 10 probes ^C cwnd 80 10.175.96.92 value ------------- Distribution ------------- count 1024 | 0 2048 | 4 4096 | 6 8192 | 18 16384 | 36 32768 |@ 79 65536 |@ 155 131072 |@ 199 262144 |@@@ 400 524288 |@@@@@@ 798 1048576 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 3848 2097152 | 0 ssthresh 80 10.175.96.92 value ------------- Distribution ------------- count 268435456 | 0 536870912 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 5543 1073741824 | 0 unacked 80 10.175.96.92 value ------------- Distribution ------------- count -1 | 0 0 | 1 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 3 512 | 0 1024 | 0 2048 | 4 4096 | 9 8192 | 21 16384 | 36 32768 |@ 78 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 5391 131072 | 0 swnd 80 10.175.96.92 value ------------- Distribution ------------- count 32768 | 0 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 5543 131072 | 0 Here we are observing a large file transfer via http on the webserver. Comparing these distributions, we can observe: That slow start congestion control is in operation. The distribution of congestion window values lies below the range of slow start threshold values (which are in the 536870912+ range), so the connection is in slow start mode. Both the unacked byte count and the send window values peak in the 65536-131071 range, but the send window value distribution is narrower. This tells us that the peer TCP's receive window is not closing. The congestion window distribution peaks in the 1048576 - 2097152 range while the receive window distribution is confined to the 65536-131071 range. Since the cwnd distribution ranges as low as 2048-4095, we can see that for some of the time we have been observing the connection, congestion control has been a limiting factor on transfer, but for the majority of the time the receive window of the peer would more likely have been the limiting factor. However, we know the window has never closed as the distribution of swnd values stays within the 65536-131071 range. So all in all we have a connection that has been mildly constrained by congestion control, but for the bulk of the time we have been observing it neither congestion or peer receive window have limited throughput. Here's the script: #!/usr/sbin/dtrace -s tcp:::send / (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { @cwnd["cwnd", args[4]-tcp_sport, args[2]-ip_daddr] = quantize(args[3]-tcps_cwnd); @ssthresh["ssthresh", args[4]-tcp_sport, args[2]-ip_daddr] = quantize(args[3]-tcps_cwnd_ssthresh); @unacked["unacked", args[4]-tcp_sport, args[2]-ip_daddr] = quantize(args[3]-tcps_snxt - args[3]-tcps_suna); @swnd["swnd", args[4]-tcp_sport, args[2]-ip_daddr] = quantize((args[4]-tcp_window)*(1 tcps_snd_ws)); } One surprise here is that slow start is still in operation - one would assume that for a large file transfer, acknowledgements would push the congestion window up past the slow start threshold over time. The slow start threshold is in fact still close to it's initial (very high) value, so that would suggest we have not experienced any congestion (the slow start threshold is adjusted when congestion occurs). Also, the above measurements were taken early in the connection lifetime, so the congestion window did not get a changes to get bumped up to the level of the slow start threshold. A good strategy when examining these sorts of measurements for a given service (such as a webserver) would be start by examining the distributions above aggregated by port number only to get an overall feel for service performance, i.e. is congestion control or peer receive window size an issue, or are we unconstrained to fill the pipe? From there, the overlap of distributions will tell us whether to drill down into specific clients. For example if the send window distribution has multiple peaks, we may want to examine if particular clients show issues with their receive window.

  Read the article

• How to get several frequency ranges at the same time in fmod?

  - by Rootosaurus

  After reading documentation and tutorials about fmod I still have a question about frequency ranges. I've found how to get a frequency range using low and high pass DSP at the same time on the main channel, but I can't find how to get several ranges at the same time. For example I want, for a specific phase of my game, to hear range 400 to 600Hz and 1000 to 2000hz of the same sound. I tried to create a channel by range, but it doesn't seem to work (or maybe I do something wrong). How can I do that ? Thank you

  Read the article

• Handling large integers in python [migrated]

  - by Sushma Palimar

  I had written a program in python to find b such that a prime number p divides b^2-8. The range for b is [1, (p+1)/2]. For small integers it works, say only up to 7 digits. But not for large integers, say for p = 140737471578113. I get the error message for i in range (2,p1,1): MemoryError I wrote the program as #!/usr/bin/python3 p=long(raw_input('enter the prime number:')) p1=long((p+1)/2) for i in range (2,p1,1): s = long((i*i)-8) if (s%p==0): print i

  Read the article

• Need help modifying C++ application to accept continuous piped input in Linux

  - by GreeenGuru

  The goal is to mine packet headers for URLs visited using tcpdump. So far, I can save a packet header to a file using: tcpdump "dst port 80 and tcp[13] & 0x08 = 8" -A -s 300 | tee -a ./Desktop/packets.txt And I've written a program to parse through the header and extract the URL when given the following command: cat ~/Desktop/packets.txt | ./packet-parser.exe But what I want to be able to do is pipe tcpdump directly into my program, which will then log the data: tcpdump "dst port 80 and tcp[13] & 0x08 = 8" -A -s 300 | ./packet-parser.exe Here is the script as it is. The question is: how do I need to change it to support continuous input from tcpdump? #include <boost/regex.hpp> #include <fstream> #include <cstdio> // Needed to define ios::app #include <string> #include <iostream> int main() { // Make sure to open the file in append mode std::ofstream file_out("/var/local/GreeenLogger/url.log", std::ios::app); if (not file_out) std::perror("/var/local/GreeenLogger/url.log"); else { std::string text; // Get multiple lines of input -- raw std::getline(std::cin, text, '\0'); const boost::regex pattern("GET (\\S+) HTTP.*?[\\r\\n]+Host: (\\S+)"); boost::smatch match_object; bool match = boost::regex_search(text, match_object, pattern); if(match) { std::string output; output = match_object[2] + match_object[1]; file_out << output << '\n'; std::cout << output << std::endl; } file_out.close(); } } Thank you ahead of time for the help!

  Read the article

• Specializing a class template constructor

  - by SilverSun

  I'm messing around with template specialization and I ran into a problem with trying to specialize the constructor based on what policy is used. Here is the code I am trying to get to work. #include <cstdlib> #include <ctime> class DiePolicies { public: class RollOnConstruction { }; class CallMethod { }; }; #include <boost/static_assert.hpp> #include <boost/type_traits/is_same.hpp> template<unsigned sides = 6, typename RollPolicy = DiePolicies::RollOnConstruction> class Die { // policy type check BOOST_STATIC_ASSERT(( boost::is_same<RollPolicy, DiePolicies::RollOnConstruction>::value || boost::is_same<RollPolicy, DiePolicies::CallMethod>::value )); unsigned m_die; unsigned random() { return rand() % sides; } public: Die(); void roll() { m_die = random(); } operator unsigned () { return m_die + 1; } }; template<unsigned sides> Die<sides, DiePolicies::RollOnConstruction>::Die() : m_die(random()) { } template<unsigned sides> Die<sides, DiePolicies::CallMethod>::Die() : m_die(0) { } ...\main.cpp(29): error C3860: template argument list following class template name must list parameters in the order used in template parameter list ...\main.cpp(29): error C2976: 'Die' : too few template arguments ...\main.cpp(31): error C3860: template argument list following class template name must list parameters in the order used in template parameter list Those are the errors I get in Microsoft Visual Studio 2010. I'm thinking either I can't figure out the right syntax for the specialization, or maybe it isn't possible to do it this way.

  Read the article

• Detecting const-ness of nested type

  - by Channel72

  Normally, if I need to detect whether a type is const I just use boost::is_const. However, I ran into trouble when trying to detect the const-ness of a nested type. Consider the following traits template, which is specialized for const types: template <class T> struct traits { typedef T& reference; }; template <class T> struct traits<const T> { typedef T const& reference; }; The problem is that boost::is_const doesn't seem to detect that traits<const T>::reference is a const type. For example: std::cout << std::boolalpha; std::cout << boost::is_const<traits<int>::reference>::value << " "; std::cout << boost::is_const<traits<const int>::reference>::value << std::endl; This outputs: false false Why doesn't it output false true?

  Read the article

• What is the rationale to not allow overloading of C++ conversions operator with non-member function

  - by Vicente Botet Escriba

  C++0x has added explicit conversion operators, but they must always be defined as members of the Source class. The same applies to the assignment operator, it must be defined on the Target class. When the Source and Target classes of the needed conversion are independent of each other, neither the Source can define a conversion operator, neither the Target can define a constructor from a Source. Usually we get it by defining a specific function such as Target ConvertToTarget(Source& v); If C++0x allowed to overload conversion operator by non member functions we could for example define the conversion implicitly or explicitly between unrelated types. template < typename To, typename From > operator To(const From& val); For example we could specialize the conversion from chrono::time_point to posix_time::ptime as follows template < class Clock, class Duration> operator boost::posix_time::ptime( const boost::chrono::time_point<Clock, Duration>& from) { using namespace boost; typedef chrono::time_point<Clock, Duration> time_point_t; typedef chrono::nanoseconds duration_t; typedef duration_t::rep rep_t; rep_t d = chrono::duration_cast<duration_t>( from.time_since_epoch()).count(); rep_t sec = d/1000000000; rep_t nsec = d%1000000000; return posix_time::from_time_t(0)+ posix_time::seconds(static_cast<long>(sec))+ posix_time::nanoseconds(nsec); } And use the conversion as any other conversion. For a more complete description of the problem, see here or on my Boost.Conversion library.. So the question is: What is the rationale to non allow overloading of C++ conversions operator with non-member functions?

  Read the article

• Visual C++ 2010, rvalue reference bug?

  - by Sergey Shandar

  Is it a bug in Visual C++ 2010 or right behaviour? template<class T> T f(T const &r) { return r; } template<class T> T f(T &&r) { static_assert(false, "no way"); return r; } int main() { int y = 4; f(y); } I thought, the function f(T &&) should never be called but it's called with T = int &. The output: main.cpp(10): error C2338: no way main.cpp(17) : see reference to function template instantiation 'T f<int&>(T)' being compiled with [ T=int & ] Update 1 Do you know any C++x0 compiler as a reference? I've tried comeau online test-drive but could not compile r-value reference. Update 2 Workaround (using SFINAE): #include <boost/utility/enable_if.hpp> #include <boost/type_traits/is_reference.hpp> template<class T> T f(T &r) { return r; } template<class T> typename ::boost::disable_if< ::boost::is_reference<T>, T>::type f(T &&r) { static_assert(false, "no way"); return r; } int main() { int y = 4; f(y); // f(5); // generates "no way" error, as expected. }

  Read the article

• Should this work?

  - by Noah Roberts

  I am trying to specialize a metafunction upon a type that has a function pointer as one of its parameters. The code compiles just fine but it will simply not match the type. #include <iostream> #include <boost/mpl/bool.hpp> #include <boost/mpl/identity.hpp> template < typename CONT, typename NAME, typename TYPE, TYPE (CONT::*getter)() const, void (CONT::*setter)(TYPE const&) > struct metafield_fun {}; struct test_field {}; struct test { int testing() const { return 5; } void testing(int const&) {} }; template < typename T > struct field_writable : boost::mpl::identity<T> {}; template < typename CONT, typename NAME, typename TYPE, TYPE (CONT::*getter)() const > struct field_writable< metafield_fun<CONT,NAME,TYPE,getter,0> > : boost::mpl::false_ {}; typedef metafield_fun<test, test_field, int, &test::testing, 0> unwritable; int main() { std::cout << typeid(field_writable<unwritable>::type).name() << std::endl; std::cin.get(); } Output is always the type passed in, never bool_.

  Read the article

• SQL SERVER – How to Roll Back SQL Server Database Changes

  - by Pinal Dave

  In a perfect scenario, no unexpected and unplanned changes occur. There are no unpleasant surprises, no inadvertent changes. However, even with all precautions and testing, there is sometimes a need to revert a structure or data change. One of the methods that can be used in this situation is to use an older database backup that has the records or database object structure you want to revert to. For this method, you have to have the adequate full database backup and a tool that will help you with comparison and synchronization is preferred. In this article, we will focus on another method: rolling back the changes. This can be done by using: An option in SQL Server Management Studio T-SQL, or ApexSQL Log The first two solutions have been described in this article The disadvantages of these methods are that you have to know when exactly the change you want to revert happened and that all transactions on the database executed in a specific time range are rolled back – the ones you want to undo and the ones you don’t. How to easily roll back SQL Server database changes using ApexSQL Log? The biggest challenge is to roll back just specific changes, not all changes that happened in a specific time range. While SQL Server Management Studio option and T-SQL read and roll forward all transactions in the transaction log files, I will show you a solution that finds and scripts only the specific changes that match your criteria. Therefore, you don’t need to worry about all other database changes that you don’t want to roll back. ApexSQL Log is a SQL Server disaster recovery tool that reads transaction logs and provides a wide range of filters that enable you to easily rollback only specific data changes. First, connect to the online database where you want to roll back the changes. Once you select the database, ApexSQL Log will show its recovery model. Note that changes can be rolled back even for a database in the Simple recovery model, when no database and transaction log backups are available. However, ApexSQL Log achieves best results when the database is in the Full recovery model and you have a chain of subsequent transaction log backups, back to the moment when the change occurred. In this example, we will use only the online transaction log. In the next step, use filters to read only the transactions that happened in a specific time range. To remove noise, it’s recommended to use as many filters as possible. Besides filtering by the time of the transaction, ApexSQL Log can filter by the operation type: Table name: As well as transaction state (committed, aborted, running, and unknown), name of the user who committed the change, specific field values, server process IDs, and transaction description. You can select only the tables affected by the changes you want to roll back. However, if you’re not certain which tables were affected, you can leave them all selected and once the results are shown in the main grid, analyze them to find the ones you to roll back. When you set the filters, you can select how to present the results. ApexSQL Log can automatically create undo or redo scripts, export the transactions into an XML, HTML, CSV, SQL, or SQL Bulk file, and create a batch file that you can use for unattended transaction log reading. In this example, I will open the results in the grid, as I want to analyze them before rolling back the transactions. The results contain information about the transaction, as well as who and when made it. For UPDATEs, ApexSQL Log shows both old and new values, so you can easily see what has happened. To create an UNDO script that rolls back the changes, select the transactions you want to roll back and click Create undo script in the menu. For the DELETE statement selected in the screenshot above, the undo script is: INSERT INTO [Sales].[PersonCreditCard] ([BusinessEntityID], [CreditCardID], [ModifiedDate]) VALUES (297, 8010, '20050901 00:00:00.000') When it comes to rolling back database changes, ApexSQL Log has a big advantage, as it rolls back only specific transactions, while leaving all other transactions that occurred at the same time range intact. That makes ApexSQL Log a good solution for rolling back inadvertent data and schema changes on your SQL Server databases. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: ApexSQL

  Read the article

• Exploring TCP throughput with DTrace

  - by user12820842

  One key measure to use when assessing TCP throughput is assessing the amount of unacknowledged data in the pipe. This is sometimes termed the Bandwidth Delay Product (BDP) (note that BDP is often used more generally as the product of the link capacity and the end-to-end delay). In DTrace terms, the amount of unacknowledged data in bytes for the connection is the different between the next sequence number to send and the lowest unacknoweldged sequence number (tcps_snxt - tcps_suna). According to the theory, when the number of unacknowledged bytes for the connection is less than the receive window of the peer, the path bandwidth is the limiting factor for throughput. In other words, if we can fill the pipe without the peer TCP complaining (by virtue of its window size reaching 0), we are purely bandwidth-limited. If the peer's receive window is too small however, the sending TCP has to wait for acknowledgements before it can send more data. In this case the round-trip time (RTT) limits throughput. In such cases the effective throughput limit is the window size divided by the RTT, e.g. if the window size is 64K and the RTT is 0.5sec, the throughput is 128K/s. So a neat way to visually determine if the receive window of clients may be too small should be to compare the distribution of BDP values for the server versus the client's advertised receive window. If the BDP distribution overlaps the send window distribution such that it is to the right (or lower down in DTrace since quantizations are displayed vertically), it indicates that the amount of unacknowledged data regularly exceeds the client's receive window, so that it is possible that the sender may have more data to send but is blocked by a zero-window on the client side. In the following example, we compare the distribution of BDP values to the receive window advertised by the receiver (10.175.96.92) for a large file download via http. # dtrace -s tcp_tput.d ^C BDP(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count -1 | 0 0 | 6 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 3 512 | 0 1024 | 0 2048 | 9 4096 | 14 8192 | 27 16384 | 67 32768 |@@ 1464 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 32396 131072 | 0 SWND(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count 16384 | 0 32768 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 17067 65536 | 0 Here we have a puzzle. We can see that the receiver's advertised window is in the 32768-65535 range, while the amount of unacknowledged data in the pipe is largely in the 65536-131071 range. What's going on here? Surely in a case like this we should see zero-window events, since the amount of data in the pipe regularly exceeds the window size of the receiver. We can see that we don't see any zero-window events since the SWND distribution displays no 0 values - it stays within the 32768-65535 range. The explanation is straightforward enough. TCP Window scaling is in operation for this connection - the Window Scale TCP option is used on connection setup to allow a connection to advertise (and have advertised to it) a window greater than 65536 bytes. In this case the scaling shift is 1, so this explains why the SWND values are clustered in the 32768-65535 range rather than the 65536-131071 range - the SWND value needs to be multiplied by two since the reciever is also scaling its window by a shift factor of 1. Here's the simple script that compares BDP and SWND distributions, fixed to take account of window scaling. #!/usr/sbin/dtrace -s #pragma D option quiet tcp:::send / (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { @bdp["BDP(bytes)", args[2]-ip_daddr, args[4]-tcp_sport] = quantize(args[3]-tcps_snxt - args[3]-tcps_suna); } tcp:::receive / (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { @swnd["SWND(bytes)", args[2]-ip_saddr, args[4]-tcp_dport] = quantize((args[4]-tcp_window)*(1 tcps_snd_ws)); } And here's the fixed output. # dtrace -s tcp_tput_scaled.d ^C BDP(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count -1 | 0 0 | 39 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 3 512 | 0 1024 | 0 2048 | 4 4096 | 9 8192 | 22 16384 | 37 32768 |@ 99 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 3858 131072 | 0 SWND(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count 512 | 0 1024 | 1 2048 | 0 4096 | 2 8192 | 4 16384 | 7 32768 | 14 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 1956 131072 | 0

  Read the article

• Optimized Image Loading in a UIScrollView

  - by Michael Gaylord

  I have a UIScrollView that has a set of images loaded side-by-side inside it. You can see an example of my app here: http://www.42restaurants.com. My problem comes in with memory usage. I want to lazy load the images as they are about to appear on the screen and unload images that aren't on screen. As you can see in the code I work out at a minimum which image I need to load and then assign the loading portion to an NSOperation and place it on an NSOperationQueue. Everything works great apart from a jerky scrolling experience. I don't know if anyone has any ideas as to how I can make this even more optimized, so that the loading time of each image is minimized or so that the scrolling is less jerky. - (void)scrollViewDidScroll:(UIScrollView *)scrollView{ [self manageThumbs]; } - (void) manageThumbs{ int centerIndex = [self centerThumbIndex]; if(lastCenterIndex == centerIndex){ return; } if(centerIndex >= totalThumbs){ return; } NSRange unloadRange; NSRange loadRange; int totalChange = lastCenterIndex - centerIndex; if(totalChange > 0){ //scrolling backwards loadRange.length = fabsf(totalChange); loadRange.location = centerIndex - 5; unloadRange.length = fabsf(totalChange); unloadRange.location = centerIndex + 6; }else if(totalChange < 0){ //scrolling forwards unloadRange.length = fabsf(totalChange); unloadRange.location = centerIndex - 6; loadRange.length = fabsf(totalChange); loadRange.location = centerIndex + 5; } [self unloadImages:unloadRange]; [self loadImages:loadRange]; lastCenterIndex = centerIndex; return; } - (void) unloadImages:(NSRange)range{ UIScrollView *scrollView = (UIScrollView *)[[self.view subviews] objectAtIndex:0]; for(int i = 0; i < range.length && range.location + i < [scrollView.subviews count]; i++){ UIView *subview = [scrollView.subviews objectAtIndex:(range.location + i)]; if(subview != nil && [subview isKindOfClass:[ThumbnailView class]]){ ThumbnailView *thumbView = (ThumbnailView *)subview; if(thumbView.loaded){ UnloadImageOperation *unloadOperation = [[UnloadImageOperation alloc] initWithOperableImage:thumbView]; [queue addOperation:unloadOperation]; [unloadOperation release]; } } } } - (void) loadImages:(NSRange)range{ UIScrollView *scrollView = (UIScrollView *)[[self.view subviews] objectAtIndex:0]; for(int i = 0; i < range.length && range.location + i < [scrollView.subviews count]; i++){ UIView *subview = [scrollView.subviews objectAtIndex:(range.location + i)]; if(subview != nil && [subview isKindOfClass:[ThumbnailView class]]){ ThumbnailView *thumbView = (ThumbnailView *)subview; if(!thumbView.loaded){ LoadImageOperation *loadOperation = [[LoadImageOperation alloc] initWithOperableImage:thumbView]; [queue addOperation:loadOperation]; [loadOperation release]; } } } } EDIT: Thanks for the really great responses. Here is my NSOperation code and ThumbnailView code. I tried a couple of things over the weekend but I only managed to improve performance by suspending the operation queue during scrolling and resuming it when scrolling is finished. Here are my code snippets: //In the init method queue = [[NSOperationQueue alloc] init]; [queue setMaxConcurrentOperationCount:4]; //In the thumbnail view the loadImage and unloadImage methods - (void) loadImage{ if(!loaded){ NSString *filename = [NSString stringWithFormat:@"%03d-cover-front", recipe.identifier, recipe.identifier]; NSString *directory = [NSString stringWithFormat:@"RestaurantContent/%03d", recipe.identifier]; NSString *path = [[NSBundle mainBundle] pathForResource:filename ofType:@"png" inDirectory:directory]; UIImage *image = [UIImage imageWithContentsOfFile:path]; imageView = [[ImageView alloc] initWithImage:image andFrame:CGRectMake(0.0f, 0.0f, 176.0f, 262.0f)]; [self addSubview:imageView]; [self sendSubviewToBack:imageView]; [imageView release]; loaded = YES; } } - (void) unloadImage{ if(loaded){ [imageView removeFromSuperview]; imageView = nil; loaded = NO; } } Then my load and unload operations: - (id) initWithOperableImage:(id<OperableImage>) anOperableImage{ self = [super init]; if (self != nil) { self.image = anOperableImage; } return self; } //This is the main method in the load image operation - (void)main { [image loadImage]; } //This is the main method in the unload image operation - (void)main { [image unloadImage]; }

  Read the article

• MultiWidget in MultiWidget how to compress the first one?

  - by sacabuche

  I have two MultiWidget one inside the other, but the problem is that the MultiWidget contained don't return compress, how do i do to get the right value from the first widget? In this case from SplitTimeWidget class SplitTimeWidget(forms.MultiWidget): """ Widget written to split widget into hours and minutes. """ def __init__(self, attrs=None): widgets = ( forms.Select(attrs=attrs, choices=([(hour,hour) for hour in range(0,24)])), forms.Select(attrs=attrs, choices=([(minute, str(minute).zfill(2)) for minute in range(0,60)])), ) super(SplitTimeWidget, self).__init__(widgets, attrs) def decompress(self, value): if value: return [value.hour, value.minute] return [None, None] class DateTimeSelectWidget (forms.MultiWidget): """ A widget that splits date into Date and Hours, minutes, seconds with selects """ date_format = DateInput.format def __init__(self, attrs=None, date_format=None): if date_format: self.date_format = date_format #if time_format: # self.time_format = time_format hours = [(hour,str(hour)+' h') for hour in range(0,24)] minutes = [(minute,minute) for minute in range(0,60)] seconds = minutes #not used always in 0s widgets = ( DateInput(attrs=attrs, format=self.date_format), SplitTimeWidget(attrs=attrs), ) super(DateTimeSelectWidget,self).__init__(widgets, attrs) def decompress(self, value): if value: return [value.date(), value.time()] else: [None, None, None]

  Read the article

• Creating a function in ruby

  - by Micke

  Hello, i have some problem with creating a function to my Rails app. I want it to work like this: str = "string here" if str.within_range?(3..30) puts "It's withing the range!" end To do that i added this into my application helper: def within_range?(range) if self.is_a?(String) (range).include?(self.size) elsif self.is_a?(Integer) (range).include?(self) end end But i get this error: undefined method `within_range?' for &quot;&quot;:String Do you know what the problem is? and could you please help me. If there is a easier way please say so then. Thanks in advance, Micke.

  Read the article

< Previous Page | 62 63 64 65 66 67 68 69 70 71 72 73  | Next Page >