Search Results

Search found 981 results on 40 pages for 'weak ptr'.

Page 12/40 | < Previous Page | 8 9 10 11 12 13 14 15 16 17 18 19  | Next Page >

• Identifying the cause of my DNS failure (domain not propagating)

  - by thejartender

  I have set up a DNS server with the help of two helpful tutorials: http://linuxconfig.org/linux-dns-server-bind-configuration http://ulyssesonline.com/2007/11/07/how-to-setup-a-dns-server-in-ubuntu/ I am using: Ubuntu Bind9 and had issues I tried negating on my own thanks to a question I posted here earlier that pointed out my mistake of using rfc 1918 addresses in my previous SOA record: $TTL 3D @ IN SOA ns.thejarbar.org. email. ( 13112012 28800 3600 604800 38400 ); thejarbar.org. IN A 10.0.0.42 @ IN NS ns.thejarbar,org. yuccalaptop IN A 10.0.0.19 ns IN A 10.0.0.42 gw IN A 10.0.0.138 www IN CNAME thejarbar.org. $TTL 600 0.0.10.in-addr.arpa. IN SOA ns.thejarbar.org. email. ( 13112012 28800 3600 604800 38400 ); 0.0.10.in-addr.arpa. IN NS ns.thejarbar.org. 42 IN PTR thejarbar.org. 19 IN PTR yuccalaptop.thejarbar.org. 138 IN PTR gw.thejarbar.org. I read the ranges that are used under rfc 1918 and modified my routers resource pool to assign LAN devices IP(s) within the 30.0.0.0 range and now modified my SOA to: $TTL 600 @ IN SOA ns.thejarbar.org. email. ( 13112012 28800 3600 604800 38400 ); thejarbar.org. IN A 30.0.0.42 @ IN NS ns.thejarbar,org. yuccalaptop IN A 10.0.0.19 ns IN A 30.0.0.42 gw IN A 30.0.0.138 www IN CNAME thejarbar.org. $TTL600 0.0.10.in-addr.arpa. IN SOA ns.thejarbar.org. email. ( 13112012 28800 3600 604800 38400 ); 0.0.30.in-addr.arpa. IN NS ns.thejarbar.org. 42 IN PTR thejarbar.org. 19 IN PTR yuccalaptop.thejarbar.org. 138 IN PTR gw.thejarbar.org. I can ping my nameserverver ns.thejarbar.organd it gives me the correct isp IP address, but my domain never seems to propagate to my nameserver. I have searched for a concise tutorial that covers setting up a DNS with a nameserver that hosts (my) or the site. I am fully aware that this is not recommended and am using this for my learning purposes. Getting to the question, due to the lack of information in tutorials I looked at (nothing about rfc 1918 and no example of swapping these with ISP IP) is my router modification going to help me as it does not seem to be. I have also tried as recommended using my ISP IP instead of the values I posted. My site never propagated to my nameserver. What could be causing this? I have run dig thejarbar.org @88.89.190.171 and get an authorative response. Can anyone assist me with the final steps I may be missing here?

  Read the article

• C++ Conceptual problem with (Pointer) Pointers

  - by Ptr

  I have a structure usually containing a pointer to an int. However, in some special cases, it is necessary that this int pointer points to another pointer which then points to an int. Wow: I mentioned the word pointer 5 times so far! Is this even possible? I thought about it that way: Instead of using a second int pointer, which is most likely not possible as my main int pointer can only point to an int and not to another int pointer, I could make it a reference like this: int intA = 1; int intB = 2; int& intC = intB; int* myPointers[ 123 ]; myPointers[ 0 ] = &intA; myPointers[ 1 ] = &intB; myPointers[ 3 ] = &intC; So the above would do what I want: The reference to intB (intC) behaves quite like I want it to (If it gets changed it also changes intB) The problem: I can't change references once they are set, right? Or is there a way? Everything in short: How do I get a value to work with * (pointers) and ** (pointers to pointers)?

  Read the article

• domain/IN: has no NS records

  - by thejartender

  I have set up a home web server using Ubuntu 12.10 and I can safely say that it works with regards to router forwarding and ports being found. I know this, because switched my hosting provider's VPS SOA record to use my ISP IP with an 'A' value and had my website running from home. This verified that my server was configured correctly so I started what I believe to be the final step in making my old desktop into a full DNS server. I found this tutorial that got me started My LAN network consists of the following: My router with a gateway of 10.0.0.zzz My server with an IP of 10.0.0.xxx A laptop with an IP of 10.0.0.yyy Step 1: I installed bind via sudo apt-get install bind9 Step2: I configured /etc/bind/named.conf.local with: zone "sognwebdesign.no" { type master; file "/etc/bind/zones/sognwebdesign.no.db"; }; zone "0.0.10.in-addr.arpa" { type master; file "/etc/bind/zones/rev.0.0.10.in-addr.arpa"; }; Step3: Updated /etc/bind/named.conf.options with two ISP DNS addresses Step 4: Updated /etc/resolv.confwith: nameserver 10.0.0.xxx search lan search sognwebdesign.no Step5: created a ``/etc/bind/zones directory Step6: Created /etc/bind/zones/sognwebdesign.no.dbwith: $TTL 3D @ IN SOA ns.sognwebdesign.no. admin.sognwebdesign.no. ( 2007062001 28800 3600 604800 38400 ); sognwebdesign.no. IN NS ns1.sognwebdesign.no. sognwebdesign.no. IN NS ns2.sognwebdesign.no. sognwebdesign.no. IN NS ns3.sognwebdesign.no. NS1 IN A 10.0.0.1 NS2 IN A 10.0.0.2 NS3 IN A 10.0.0.3 www IN A 10.0.0.4 yuccalaptop IN A 10.0.0.19 gw IN A 10.0.0.138 TXT "Network Gateway" Step 7: created/etc/bind/zones/rev.0.0.10.in-addr.arpawith: $TTL 3D @ IN SOA ns.sognwebdesign.no. admin.sognwebdesign.no. ( 2007062001 28800 604800 604800 86400 ); zzz IN PTR gw.sognwebdesign.no. 1 IN PTR ns1.sognwebdesign.no. 2 IN PTR ns2.sognwebdesign.no. 3 IN PTR ns3.sognwebdesign.no. yyy IN PTR yuccalaptop.sognwebdesign.no. I then restart bind and dig-x sognwebdesign.no and it works Lastly I perform named-checkzoneon each of my zone files, but me reverse zone fail fails with: sognwedesign.no/IN: has no NS records Can anyone explain what I am doing wrong here or assist me in getting this configured correctly?

  Read the article

• Passing a template func. as a func. ptr to an overloaded func. - is there a way to compile this code

  - by LoudNPossiblyRight

  Just a general c++ curiosity: This code below shouldn't compile because it's impossible to know which to instantiate: temp(const int&) or temp(const string&) when calling func(temp) - this part i know. What i would like to know is if there is anything i can do to the line marked PASSINGLINE to get the compiler to deduce that i want FPTR1 called and not FPTR2 ? #include<iostream> using std::cout; using std::endl; /*FPTR1*/ void func(void(*fptr)(const int&)){ fptr(1001001);} /*FPTR2*/ void func(void(*fptr)(const string&)){ fptr("1001001"); } template <typename T> void temp(const T &t){ cout << t << endl; } int main(){ /*PASSINGLINE*/ func(temp); return 0; } Thank you.

  Read the article

• How can I generate a view or projection matrix for OpenGL 3.+

  - by Ken

  I'm transitioning from OpenGL 2 to OpenGL 3.+ and to GLSL 1.5. I'm trying to avoid using the deprecated features. My question how do we now generate the view or projection matrix. I was using the matrix stack to calculate the projection matrix for me; GLfloat ptr[16]; gluPerspective(...); glGetFloatv(GL_MODELVIEW_MATRIX, ptr); //then pass ptr via a uniform to the shader But obviously the matrix stack is deprecated. So this approach is not the best an option going forward. I have the 'Red Book', 7th ed, which covers 3.0 & 3.1 and it still uses the deprecated matrix functions in it's examples. I could write some utility-code myself to generate the matrices. But I don't want to re-invent this particular wheel, especially when this functionality is required for every 3D graphics program. What is the accepted way to generate world,view & projection matrices for OpenGL? Is there an emerging 'standard' library for this? Or is there some other hidden (to me) functionality in OpenGL/GLSL which I have overlooked?

  Read the article

• Does RDNS for mail server have to match the mail server hostname exactly?

  - by threecheeseopera

  Typically when setting up a mail server, I create an rDNS record for the mail server IP to match the mail server hostname (ex: mail.example.com). Can I instead set the rDNS ptr to match the parent domain (e.g. example.com), if this server is being used for multiple purposes, and still send mail successfully (i.e. not be classified as spam b/c of mismatched rDNS)? Thanks! EDIT: The article at http://en.wikipedia.org/wiki/Forward_Confirmed_reverse_DNS seems to indicate that it might be more complicated than I had thought. For instance, 1) I did not know that you could have multiple PTR records for a given IP; 2) it appears that as long as each PTR record matches an A record, everything is good (basically nullifying my question). Would you agree?

  Read the article

• Run script when POST data is sent to Apache

  - by Nathan Adams

  Among my several years of running servers there seems to be a pattern with most spam activity. My question/idea is that is there a way to tell Apache to run a script when POST data is detected? What I would want to do is perform a reverse DNS lookup on the client's IP address, and then perform a DNS lookup on the hostname in the PTR record. Afterwards, perform some checks, excuse the pseudo-code: if PTR does not exist: deny POST request if IP of PTR hostname = client's IP Allow POST request else deny POST request Though I don't care about GET requests, even though they can be just as malicious, this idea is targeted towards spam comments which use POST data to send the comment data to the web server. In order to make sure there isn't much of a time delay, I would run my own recursive DNS server. Please do note, this isn't meant to be a sliver bullet to spam, but it should decrease the volume. Possible or impossible?

  Read the article

• How to draw an E-R diagram?

  - by Appy

  I am learning DBMS in my college. Recently I was given an assignment to draw a E-R Model of a Bus Reservation system which handles Reservations, Ticketing and cancellations. I understand the theory about E-R model when I study from a book, but it gets confusing when I try to draw one from scratch. How should one proceed? There seem to be a lot of ways to model a E-R diagram for a particular requirement. It's really confusing. Can anyone explain taking Bus reservation System as an example? Here is the model I made (But I am not confident with it because at every step, I could think of many more alternatives!) - Entity_Set Passenger(passengerID,name,age,gender) Entity_Set Ticket(ticketID,status) //Status is either WaitingList , Confirmed or Cancelled Entity_Set Bus (busID,MaxSeats,Type) //Type is Ac or Non-AC Entity_Set Route(routeID,ArrivalTime,DepartureTime,Source,Destination) And a Ternary relationship between Passenger, Ticket and Bus with attributes as passengerID, ticketID, busID . Binary relationship between Bus and Route with attributes as busID, routeID . I have few doubts regarding - 1 . Should we take Time as a composite attribute with Arrival and Departure as its attributes (What's the difference if we take that way?) 2 . The same with Source and Destination. Should they be made into a composite attribute "Place" or something like "Location"? 3. Are there any weak entity sets here? Can you please 'create' a weak entity set and explain? Because I have no idea at all what to take as a Weak entity set?

  Read the article

• Choosing an open source license such that maximum value is added to a startup

  - by echo-flow

  There are many companies that produce open source software products, and many business models that these companies can use. I'm particularly interested in companies like 280 North, the company behind Objective-J and Cappucino frameworks. My understanding of this organization's business model is that they: worked to develop a tool which added significant value to developers, released the tool under an open source license, built a community around the tool (which was helped by the project's open source licensing), created interesting demos illustrating the project's value All of these things added value to the project, and the company that owned it. Finally, 280 North was sold to Motorola. My question has to do with the role of software licensing in this particular business model. 280 North licensed their software projects under the LGPL, which gave them some proprietary control over how the project could be used. I believe that the LGPL is what's known as a "weak copyleft" license, meaning that the project can be linked to, without the linking code also being licensed under the LGPL; but software derived directly from the project would need to be licensed under the LGPL. For web-oriented libraries in particular, weak copyleft, or non-copyleft licensing seems to be quite common; I can't think of a single example of a popular or well-known web-oriented library that is licensed under the GPL (or AGPL). The question then, is, how much value would a weak copyleft license like the LGPL add to a software venture like 280 North, versus a non-copyleft license, such as the BSD license or the Apache Software License? I'd really appreciate any insight anyone can offer into this, but I'd be most interested in answers that can cite other companies as case studies or examples.

  Read the article

• What does the Sys_PageIn() function do in Quake?

  - by Philip

  I've noticed in the initialization process of the original Quake the following function is called. volatile int sys_checksum; // **lots of code** void Sys_PageIn(void *ptr, int size) { byte *x; int j,m,n; //touch all memory to make sure its there. The 16-page skip is to //keep Win 95 from thinking we're trying to page ourselves in (we are //doing that, of course, but there's no reason we shouldn't) x = (byte *)ptr; for (n=0 ; n<4 ; n++) { for (m=0; m<(size - 16 * 0x1000) ; m += 4) { sys_checksum += *(int *)&x[m]; sys_checksum += *(int *)&x[m + 16 * 0x10000]; } } } I think I'm just not familiar enough with paging to understand this function. the void* ptr passed to the function is a recently malloc()'d piece of memory that is size bytes big. This is the whole function - j is an unreferenced variable. My best guess is that the volatile int sys_checksum is forcing the system to physically read all of the space that was just malloc()'d, perhaps to ensure that these spaces exist in virtual memory? Is this right? And why would someone do this? Is it for some antiquated Win95 reason?

  Read the article

• gem install of mongrel

  - by atlantis

  I initiated myself into rails development yesterday. I installed ruby 1.9.1 , rubygems and rails. Running 'gem install mongrel' worked fine and ostensibly installed mongrel too. I am slightly puzzled because script/server starts webrick by default 'which mongrel' returns nothing 'locate mongrel' returns lots of entries like . /Developer/SDKs/MacOSX10.5.sdk/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1 /Developer/SDKs/MacOSX10.5.sdk/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib /Developer/SDKs/MacOSX10.5.sdk/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel . . . /usr/local/bin/mongrel_rails /usr/local/lib/ruby/gems/1.9.1/cache/mongrel-1.1.5.gem /usr/local/lib/ruby/gems/1.9.1/doc/actionpack-2.3.2/rdoc/files/lib/action_controller/vendor/rack-1_0/rack/handler/evented_mongrel_rb.html /usr/local/lib/ruby/gems/1.9.1/doc/actionpack-2.3.2/rdoc/files/lib/action_controller/vendor/rack-1_0/rack/handler/mongrel_rb.html /usr/local/lib/ruby/gems/1.9.1/doc/actionpack-2.3.2/rdoc/files/lib/action_controller/vendor/rack-1_0/rack/handler/swiftiplied_mongrel_rb.html /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/handler/evented_mongrel.rb /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/handler/mongrel.rb /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/handler/swiftiplied_mongrel.rb /usr/local/lib/ruby/gems/1.9.1/gems/mongrel-1.1.5 . . . Does look like I have mongrel installed (both the default installation and my custom install). So why doesn't which mongrel return something. Also trying to reinstall mongrel using 'gem install mongrel' returns throws its own set of exceptions : Building native extensions. This could take a while... ERROR: Error installing mongrel: ERROR: Failed to build gem native extension. /usr/local/bin/ruby extconf.rb install mongrel checking for main() in -lc... yes creating Makefile make gcc -I. -I/usr/local/include/ruby-1.9.1/i386-darwin9.7.0 -I/usr/local/include/ruby-1.9.1/ruby/backward -I/usr/local/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -fno-common -D_XOPEN_SOURCE=1 -O2 -g -Wall -Wno-parentheses -fno-common -pipe -fno-common -o http11.o -c http11.c http11.c: In function 'http_field': http11.c:77: error: 'struct RString' has no member named 'ptr' http11.c:77: error: 'struct RString' has no member named 'len' http11.c:77: warning: left-hand operand of comma expression has no effect http11.c:77: warning: statement with no effect http11.c: In function 'header_done': http11.c:172: error: 'struct RString' has no member named 'ptr' http11.c:174: error: 'struct RString' has no member named 'ptr' http11.c:176: error: 'struct RString' has no member named 'ptr' http11.c:177: error: 'struct RString' has no member named 'len' http11.c: In function 'HttpParser_execute': http11.c:298: error: 'struct RString' has no member named 'ptr' http11.c:299: error: 'struct RString' has no member named 'len' make: *** [http11.o] Error 1

  Read the article

• `gem install mongrel` fails with ruby 1.9.1

  - by atlantis

  I initiated myself into rails development yesterday. I installed ruby 1.9.1, rubygems and rails. Running gem install mongrel worked fine and ostensibly installed mongrel too. I am slightly puzzled because: script/server starts webrick by default which mongrel returns nothing locate mongrel returns lots of entries like /Developer/SDKs/MacOSX10.5.sdk/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1 /Developer/SDKs/MacOSX10.5.sdk/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib /Developer/SDKs/MacOSX10.5.sdk/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel . . . /usr/local/bin/mongrel_rails /usr/local/lib/ruby/gems/1.9.1/cache/mongrel-1.1.5.gem /usr/local/lib/ruby/gems/1.9.1/doc/actionpack-2.3.2/rdoc/files/lib/action_controller/vendor/rack-1_0/rack/handler/evented_mongrel_rb.html /usr/local/lib/ruby/gems/1.9.1/doc/actionpack-2.3.2/rdoc/files/lib/action_controller/vendor/rack-1_0/rack/handler/mongrel_rb.html /usr/local/lib/ruby/gems/1.9.1/doc/actionpack-2.3.2/rdoc/files/lib/action_controller/vendor/rack-1_0/rack/handler/swiftiplied_mongrel_rb.html /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/handler/evented_mongrel.rb /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/handler/mongrel.rb /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/handler/swiftiplied_mongrel.rb /usr/local/lib/ruby/gems/1.9.1/gems/mongrel-1.1.5 . . . Does look like I have mongrel installed (both the default installation and my custom install). So why doesn't which mongrel return something. Also trying to reinstall mongrel using gem install mongrel returns throws its own set of exceptions: Building native extensions. This could take a while... ERROR: Error installing mongrel: ERROR: Failed to build gem native extension. /usr/local/bin/ruby extconf.rb install mongrel checking for main() in -lc... yes creating Makefile make gcc -I. -I/usr/local/include/ruby-1.9.1/i386-darwin9.7.0 -I/usr/local/include/ruby-1.9.1/ruby/backward -I/usr/local/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -fno-common -D_XOPEN_SOURCE=1 -O2 -g -Wall -Wno-parentheses -fno-common -pipe -fno-common -o http11.o -c http11.c http11.c: In function 'http_field': http11.c:77: error: 'struct RString' has no member named 'ptr' http11.c:77: error: 'struct RString' has no member named 'len' http11.c:77: warning: left-hand operand of comma expression has no effect http11.c:77: warning: statement with no effect http11.c: In function 'header_done': http11.c:172: error: 'struct RString' has no member named 'ptr' http11.c:174: error: 'struct RString' has no member named 'ptr' http11.c:176: error: 'struct RString' has no member named 'ptr' http11.c:177: error: 'struct RString' has no member named 'len' http11.c: In function 'HttpParser_execute': http11.c:298: error: 'struct RString' has no member named 'ptr' http11.c:299: error: 'struct RString' has no member named 'len' make: *** [http11.o] Error 1

  Read the article

• wrapping boost::ublas with swig

  - by leon

  I am trying to pass data around the numpy and boost::ublas layers. I have written an ultra thin wrapper because swig cannot parse ublas' header correctly. The code is shown below #include <boost/numeric/ublas/vector.hpp> #include <boost/numeric/ublas/matrix.hpp> #include <boost/lexical_cast.hpp> #include <algorithm> #include <sstream> #include <string> using std::copy; using namespace boost; typedef boost::numeric::ublas::matrix<double> dm; typedef boost::numeric::ublas::vector<double> dv; class dvector : public dv{ public: dvector(const int rhs):dv(rhs){;}; dvector(); dvector(const int size, double* ptr):dv(size){ copy(ptr, ptr+sizeof(double)*size, &(dv::data()[0])); } ~dvector(){} }; with the SWIG interface that looks something like %apply(int DIM1, double* INPLACE_ARRAY1) {(const int size, double* ptr)} class dvector{ public: dvector(const int rhs); dvector(); dvector(const int size, double* ptr); %newobject toString; char* toString(); ~dvector(); }; I have compiled them successfully via gcc 4.3 and vc++9.0. However when I simply run a = dvector(array([1.,2.,3.])) it gives me a segfault. This is the first time I use swigh with numpy and not have fully understanding between the data conversion and memory buffer passing. Does anyone see something obvious I have missed? I have tried to trace through with a debugger but it crashed within the assmeblys of python.exe. I have no clue if this is a swig problem or of my simple wrapper. Anything is appreciated.

  Read the article

• How to obtain a pointer out of a C++ vtable?

  - by Josh Haberman

  Say you have a C++ class like: class Foo { public: virtual ~Foo() {} virtual DoSomething() = 0; }; The C++ compiler translates a call into a vtable lookup: Foo* foo; // Translated by C++ to: // foo->vtable->DoSomething(foo); foo->DoSomething(); Suppose I was writing a JIT compiler and I wanted to obtain the address of the DoSomething() function for a particular instance of class Foo, so I can generate code that jumps to it directly instead of doing a table lookup and an indirect branch. My questions are: Is there any standard C++ way to do this (I'm almost sure the answer is no, but wanted to ask for the sake of completeness). Is there any remotely compiler-independent way of doing this, like a library someone has implemented that provides an API for accessing a vtable? I'm open to completely hacks, if they will work. For example, if I created my own derived class and could determine the address of its DoSomething method, I could assume that the vtable is the first (hidden) member of Foo and search through its vtable until I find my pointer value. However, I don't know a way of getting this address: if I write &DerivedFoo::DoSomething I get a pointer-to-member, which is something totally different. Maybe I could turn the pointer-to-member into the vtable offset. When I compile the following: class Foo { public: virtual ~Foo() {} virtual void DoSomething() = 0; }; void foo(Foo *f, void (Foo::*member)()) { (f->*member)(); } On GCC/x86-64, I get this assembly output: Disassembly of section .text: 0000000000000000 <_Z3fooP3FooMS_FvvE>: 0: 40 f6 c6 01 test sil,0x1 4: 48 89 74 24 e8 mov QWORD PTR [rsp-0x18],rsi 9: 48 89 54 24 f0 mov QWORD PTR [rsp-0x10],rdx e: 74 10 je 20 <_Z3fooP3FooMS_FvvE+0x20> 10: 48 01 d7 add rdi,rdx 13: 48 8b 07 mov rax,QWORD PTR [rdi] 16: 48 8b 74 30 ff mov rsi,QWORD PTR [rax+rsi*1-0x1] 1b: ff e6 jmp rsi 1d: 0f 1f 00 nop DWORD PTR [rax] 20: 48 01 d7 add rdi,rdx 23: ff e6 jmp rsi I don't fully understand what's going on here, but if I could reverse-engineer this or use an ABI spec I could generate a fragment like the above for each separate platform, as a way of obtaining a pointer out of a vtable.

  Read the article

• Memory corruption in System.Move due to changed 8087CW mode (png + stretchblt)

  - by André Mussche

  I have strange a memory corruption problem. After many hours debugging and trying I think I found something. For example: I do a simple string assignment: sTest := 'SET LOCK_TIMEOUT '; However, the result sometimes becomes: sTest = 'SET LOCK'#0'TIMEOUT ' So, the _ gets replaced by an 0 byte. I have seen this happening once (reproducing is tricky, dependent on timing) in the System.Move function, when it uses the FPU stack (fild, fistp) for fast memory copy (in case of 9 till 32 bytes to move): ... @@SmallMove: {9..32 Byte Move} fild qword ptr [eax+ecx] {Load Last 8} fild qword ptr [eax] {Load First 8} cmp ecx, 8 jle @@Small16 fild qword ptr [eax+8] {Load Second 8} cmp ecx, 16 jle @@Small24 fild qword ptr [eax+16] {Load Third 8} fistp qword ptr [edx+16] {Save Third 8} ... Using the FPU view and 2 memory debug views (Delphi - View - Debug - CPU - Memory) I saw it going wrong... once... could not reproduce however... This morning I read something about the 8087CW mode, and yes, if this is changed into $27F I get memory corruption! Normally it is $133F: The difference between $133F and $027F is that $027F sets up the FPU for doing less precise calculations (limiting to Double in stead of Extended) and different infiniti handling (which was used for older FPU’s, but is not used any more). Okay, now I found why but not when! I changed the working of my AsmProfiler with a simple check (so all functions are checked at enter and leave): if Get8087CW = $27F then //normally $1372? if MainThreadID = GetCurrentThreadId then //only check mainthread DebugBreak; I "profiled" some units and dll's and bingo (see stack): Windows.StretchBlt(3372289943,0,0,514,345,4211154027,0,0,514,345,13369376) pngimage.TPNGObject.DrawPartialTrans(4211154027,(0, 0, 514, 345, (0, 0), (514, 345))) pngimage.TPNGObject.Draw($7FF62450,(0, 0, 514, 345, (0, 0), (514, 345))) Graphics.TCanvas.StretchDraw((0, 0, 514, 345, (0, 0), (514, 345)),$7FECF3D0) ExtCtrls.TImage.Paint Controls.TGraphicControl.WMPaint((15, 4211154027, 0, 0)) So it is happening in StretchBlt... What to do now? Is it a fault of Windows, or a bug in PNG (included in D2007)? Or is the System.Move function not failsafe?

  Read the article

• How to access a matrix in a matlab struct's field from a mex function?

  - by B. Ruschill

  I'm trying to figure out how to access a matrix that is stored in a field in a matlab structure from a mex function. That's awfully long winded... Let me explain: I have a matlab struct that was defined like the following: matrixStruct = struct('matrix', {4, 4, 4; 5, 5, 5; 6, 6 ,6}) I have a mex function in which I would like to be able to receive a pointer to the first element in the matrix (matrix[0][0], in c terms), but I've been unable to figure out how to do that. I have tried the following: /* Pointer to the first element in the matrix (supposedly)... */ double *ptr = mxGetPr(mxGetField(prhs[0], 0, "matrix"); /* Incrementing the pointer to access all values in the matrix */ for(i = 0; i < 3; i++){ printf("%f\n", *(ptr + (i * 3))); printf("%f\n", *(ptr + 1 + (i * 3))); printf("%f\n", *(ptr + 2 + (i * 3))); } What this ends up printing is the following: 4.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 I have also tried variations of the following, thinking that perhaps it was something wonky with nested function calls, but to no avail: /* Pointer to the first location of the mxArray */ mxArray *fieldValuePtr = mxGetField(prhs[0], 0, "matrix"); /* Get the double pointer to the first location in the matrix */ double *ptr = mxGetPr(fieldValuePtr); /* Same for loop code here as written above */ Does anyone have an idea as to how I can achieve what I'm trying to, or what I am potentially doing wrong? Thanks! Edit: As per yuk's comment, I tried doing similar operations on a struct that has a field called array which is a one-dimensional array of doubles. The struct containing the array is defined as follows: arrayStruct = struct('array', {4.44, 5.55, 6.66}) I tried the following on the arrayStruct from within the mex function: mptr = mxGetPr(mxGetField(prhs[0], 0, "array")); printf("%f\n", *(mptr)); printf("%f\n", *(mptr + 1)); printf("%f\n", *(mptr + 2)); ...but the output followed what was printed earlier: 4.440000 0.000000 0.000000

  Read the article

• Determining if Memory Pointer is Valid - C++

  - by Jim Fell

  It has been my observation that if free( ptr ) is called where ptr is not a valid pointer to system-allocated memory, an access violation occurs. Let's say that I call free like this: LPVOID ptr = (LPVOID)0x12345678; free( ptr ); This will most definitely cause an access violation. Is there a way to test that the memory location pointed to by ptr is valid system-allocated memory? It seems to me that the the memory management part of the Windows OS kernel must know what memory has been allocated and what memory remains for allocation. Otherwise, how could it know if enough memory remains to satisfy a given request? (rhetorical) That said, it seems reasonable to conclude that there must be a function (or set of functions) that would allow a user to determine if a pointer is valid system-allocated memory. Perhaps Microsoft has not made these functions public. If Microsoft has not provided such an API, I can only presume that it was for an intentional and specific reason. Would providing such a hook into the system prose a significant threat to system security? Situation Report Although knowing whether a memory pointer is valid could be useful in many scenarios, this is my particular situation: I am writing a driver for a new piece of hardware that is to replace an existing piece of hardware that connects to the PC via USB. My mandate is to write the new driver such that calls to the existing API for the current driver will continue to work in the PC applications in which it is used. Thus the only required changes to existing applications is to load the appropriate driver DLL(s) at startup. The problem here is that the existing driver uses a callback to send received serial messages to the application; a pointer to allocated memory containing the message is passed from the driver to the application via the callback. It is then the responsibility of the application to call another driver API to free the memory by passing back the same pointer from the application to the driver. In this scenario the second API has no way to determine if the application has actually passed back a pointer to valid memory.

  Read the article

• bind9 DNS Ubuntu names pingible on server, but not on Windows Machines?

  - by leeand00

  I setup a DNS server today on Ubuntu, following this tutorial. My intent was to setup my network for dns-name resolving on the private LAN within a single zone (nothing fancy I just want name resolution). I've tested the setup on the DNS server machine itself, and I can ping all the machines listed in the configuration file. I've also configured the Windows Machines on my network, and for some reason they are incapable of pinging by names as was possible on the DNS Server itself. I've tried running nslookup on the Windows DNS clients and I receive and error mentioning the address of the DNS server. DNS forwarding works fine, I'm not having any trouble accessing the internet, the problem only lies within accessing names within the private LAN. Here are my configuration files: options { directory "/var/cache/bind"; // If there is a firewall between you and nameservers you want // to talk to, you may need to fix the firewall to allow multiple // ports to talk. See http://www.kb.cert.org/vuls/id/800113 // If your ISP provided one or more IP addresses for stable // nameservers, you probably want to use them as forwarders. // Uncomment the following block, and insert the addresses replacing // the all-0's placeholder. // forwarders { // 0.0.0.0; // }; forwarders { 8.8.8.8; 8.8.8.4; 74.242.0.12; //68.87.76.178; }; auth-nxdomain no; # conform to RFC1035 listen-on-v6 { any; }; }; /etc/bind/named.conf.options zone "leerdomain.local" { type master; file "/etc/bind/zones/leerdomain.local.db"; notify no; }; zone "2.168.192.in-addr.arpa" { type master; file "/etc/bind/zones/rev.2.168.192.in-addr.arpa"; notify no; }; /etc/bind/named.conf.local Lookup: $TTL 3D @ IN SOA ns.leerdomain.local. admin.leerdomain.local. ( 2010011001 28800 3600 604800 38400 ); leerdomain.local. IN NS ns.leerdomain.local. ns IN A 192.168.2.9 asus IN A 192.168.2.254 www IN CNAME asus vaio IN A 192.168.2.253 iptouch IN A 192.168.2.252 toshiba IN A 192.168.2.251 gw IN A 192.168.2.1 TXT "Network Gateway" /etc/bind/zones/leerdomain.local.db (Validates fine with named-checkzone when validating zone leerdomain.local) Reverse Lookup: $TTL 3D @ IN SOA ns.leerdomain.local. admin.leerdomain.local. ( 201001101 28800 604800 604800 86400 ) IN NS ns.leerdomain.local. 1 IN PTR gw.leerdomain.local. 254 IN PTR asus.leerdomain.local. 253 IN PTR vaio.leerdomain.local. 252 IN PTR iptouch.leerdomain.local. 251 IN PTR toshiba.leerdomain.local. /etc/bind/zones/rev.2.168.192.in-addr.arpa *(Does not validate with named-checkzone when validating zone leerdomain.local gives an error of: zone leerdomain.local/IN: NS 'ns.leerdomain.local' has no address records (A or AAAA) zone leerdomain.local/IN: not loaded due to errors. * Despite not validating bind9 starts without errors in /var/log/syslog I've also configured a few of the windows machines on my network to have the static ip as specified in the lookup and reverse lookup config files. i.e. Using nslookup yields the following results: C:\Users\leeand00>nslookup ns Server: UnKnown Address: 192.168.2.9 *** UnKnown can't find ns: Non-existent domain C:\Users\leeand00>nslookup gw Server: UnKnown Address: 192.168.2.9 Name: gw. Additionally trying to ping by name also fails on machines that are not the DNS Server. Is there something wrong with my configuration of either the nameserver or the Windows Boxes that is keeping me from accessing other machines using names?

  Read the article

• confusing fork system call

  - by benjamin button

  Hi, i was just checking the behaviour of fork system call and i found it very confusing. i saw in a website that Unix will make an exact copy of the parent's address space and give it to the child. Therefore, the parent and child processes have separate address spaces #include <stdio.h> #include <sys/types.h> int main(void) { pid_t pid; char y='Y'; char *ptr; ptr=&y; pid = fork(); if (pid == 0) { y='Z'; printf(" *** Child process ***\n"); printf(" Address is %p\n",ptr); printf(" char value is %c\n",y); sleep(5); } else { sleep(5); printf("\n ***parent process ***\n",&y); printf(" Address is %p\n",ptr); printf(" char value is %c\n",y); } } the output of the above program is : *** Child process *** Address is 69002894 char value is Z ***parent process *** Address is 69002894 char value is Y so from the above mentioned statement it seems that child and parent have separet address spaces.this is the reason why char value is printed separately and why am i seeing the address of the variable as same in both child and parent processes.? Please help me understand this!

  Read the article

• Should i enforce realloc check if the new block size is smaller than the initial ?

  - by nomemory

  Can realloc fail in this case ? int *a = NULL; a = calloc(100, sizeof(*a)); printf("1.ptr: %d \n", a); a = realloc(a, 50 * sizeof(*a)); printf("2.ptr: %d \n", a); if(a == NULL){ printf("Is it possible?"); } return (0); } The output in my case is: 1.ptr: 4072560 2.ptr: 4072560 So 'a' points to the same adress. So should i enforce realloc check ? Later edit: Using MinGW compiler under Windows XP. Is the behaviour similar with gcc on Linux ? Later edit 2: Is it OK to check this way ? int *a = NULL, *b = NULL; a = calloc(100, sizeof(*a)); b = realloc(a, 50 * sizeof(*a)); if(b == NULL){ return a; } a = b; return a;

  Read the article

• How can I declare and initialize an array of pointers to a structure in C?

  - by worlds-apart89

  I have a small assignment in C. I am trying to create an array of pointers to a structure. My question is how can I initialize each pointer to NULL? Also, after I allocate memory for a member of the array, I can not assign values to the structure to which the array element points. #include <stdio.h> #include <stdlib.h> typedef struct list_node list_node_t; struct list_node { char *key; int value; list_node_t *next; }; int main() { list_node_t *ptr = (list_node_t*) malloc(sizeof(list_node_t)); ptr->key = "Hello There"; ptr->value = 1; ptr->next = NULL; // Above works fine // Below is erroneous list_node_t **array[10] = {NULL}; *array[0] = (list_node_t*) malloc(sizeof(list_node_t)); array[0]->key = "Hello world!"; //request for member ‘key’ in something not a structure or union array[0]->value = 22; //request for member ‘value’ in something not a structure or union array[0]->next = NULL; //request for member ‘next’ in something not a structure or union // Do something with the data at hand // Deallocate memory using function free return 0; }

  Read the article

• How to change the meaning of pointer access operator

  - by kumar_m_kiran

  Hi All, This may be very obvious question, pardon me if so. I have below code snippet out of my project, #include <stdio.h> class X { public: int i; X() : i(0) {}; }; int main(int argc,char *arv[]) { X *ptr = new X[10]; unsigned index = 5; cout<<ptr[index].i<<endl; return 0; } Question Can I change the meaning of the ptr[index] ? Because I need to return the value of ptr[a[index]] where a is an array for subindexing. I do not want to modify existing source code. Any new function added which can change the behavior is needed. Since the access to index operator is in too many places (536 to be precise) in my code, and has complex formulas inside the index subscript operator, I am not inclined to change the code in many locations. PS : 1. I tried operator overload and came to conclusion that it is not possible. 2. Also p[i] will be transformed into *(p+i). I cannot redefine the basic operator '+'. So just want to reconfirm my understanding and if there are any possible short-cuts to achieve. Else I need fix it by royal method of changing every line of code :) .

  Read the article

• Make All Types Constant by Default in C++

  - by Jon Purdy

  What is the simplest and least obtrusive way to indicate to the compiler, whether by means of compiler options, #defines, typedefs, or templates, that every time I say T, I really mean T const? I would prefer not to make use of an external preprocessor. Since I don't use the mutable keyword, that would be acceptable to repurpose to indicate mutable state. Potential (suboptimal) solutions so far: // I presume redefinition of keywords is implementation-defined or illegal. #define int int const #define ptr * const int i(0); int ptr j(&i); typedef int const Int; typedef int const* const Intp; Int i(0); Intp j(&i); template<class T> struct C { typedef T const type; typedef T const* const ptr; }; C<int>::type i(0); C<int>::ptr j(&i);

  Read the article

• How can pointers to functions point to something that doesn't exist in memory yet? Why do prototypes have different addresses?

  - by Kacy Raye

  To my knowledge, functions do not get added to the stack until run-time after they are called in the main function. So how can a pointer to a function have a function's memory address if it doesn't exist in memory? For example: using namespace std; #include <iostream> void func() { } int main() { void (*ptr)() = func; cout << reinterpret_cast<void*>(ptr) << endl; //prints 0x8048644 even though func never gets added to the stack } Also, this next question is a little less important to me, so if you only know the answer to my first question, then that is fine. But anyway, why does the value of the pointer ( the memory address of the function ) differ when I declare a function prototype and implement the function after main? In the first example, it printed out 0x8048644 no matter how many times I ran the program. In the next example, it printed out 0x8048680 no matter how many times I ran the program. For example: using namespace std; #include <iostream> void func(); int main() { void ( *ptr )() = func; cout << reinterpret_cast<void*>(ptr) << endl; } void func(){ }

  Read the article

• What encoding does c32rtomb convert to?

  - by R. Martinho Fernandes

  The functions c32rtomb and mbrtoc32 from <cuchar>/<uchar.h> are described in the C Unicode TR (draft) as performing conversions between UTF-321 and "multibyte characters". (...) If s is not a null pointer, the c32rtomb function determines the number of bytes needed to represent the multibyte character that corresponds to the wide character given by c32 (including any shift sequences), and stores the multibyte character representation in the array whose first element is pointed to by s. (...) What is this "multibyte character representation"? I'm actually interested in the behaviour of the following program: #include <cassert> #include <cuchar> #include <string> int main() { std::u32string u32 = U"this is a wide string"; std::string narrow = "this is a wide string"; std::string converted(1000, '\0'); char* ptr = &converted[0]; std::mbstate_t state {}; for(auto u : u32) { ptr += std::c32rtomb(ptr, u, &state); } converted.resize(ptr - &converted[0]); assert(converted == narrow); } Is the assertion in it guaranteed to hold1? 1 Working under the assumption that __STDC_UTF_32__ is defined.

  Read the article

< Previous Page | 8 9 10 11 12 13 14 15 16 17 18 19  | Next Page >