Just wondering is this kind of code recommended to increase performance? void functionCalledLotsofTimes() { static int *localarray = NULL; //size is a large constant > 10 000 if (localarray == NULL) localarray = new int[size]; //Algorithm goes here } I'm also curious how static variables are implemented by modern c++ c...
This is a most singular problem, with many interdisciplinary ramifications. It focuses on this piece of code (file name mainpp.c): #include <stdio.h> #include <stdlib.h> int main(int argc, char *argv[]) { int status; if (fork()) { FILE *f=fopen("/tmp/gcc-trace","a"); fprintf(f,"----------------------------------...
Hi, I compiled and ran my code and got the following error: Terminating because of 6 signal What is signal 6 and what causes it? ...
I've seen in many places that people often use the option -fomit-frame-pointer when compiling C / C++ code and I wonder, is the use of that option safe? What is it used for? Thank you very much, best regards. ...
Hi, I'm trying to overload the comma operator with a non-friend non-member function like this: #include <iostream> using std::cout; using std::endl; class comma_op { int val; public: void operator,(const float &rhs) { cout << this->val << ", " << rhs << endl; } }; void operator,(const float &lhs, const comma_o...
I'd like to set up a cross-compilation environment on a Ubuntu 9.10 box. From the documents I've read so far (these ones, for example) this involves compiling the toolchain of the target platforms. My question is: how do you determine the required version of each of the packages in the toolchain for a specific target platform? Is there ...
According to my memory the following piece of code should compile fine on C++ but not in C. Only problem is how to test it? It compiled fine with g++ and also with gcc. I'm assuming that g++ is C++ compiler and gcc is C compiler. I've tried it with mingw under Windows. Am I correct? if not then how to compile it using C compiler. int ma...
So, I've been looking all over. I can't find anywhere that talks about specifically how to configure Eclipse + CDT to run the gcc / gcc++ compiler. I am running Eclipse on a windows box, but I've installed Cygwin. [edit] I've installed Cygwin, and I've added C:\Cygwin\bin to my path environment variable. I'm now getting this error...
Hello - I'm working on a hw problem that requires disabling compiler optimization protection for it to work. I'm using gcc 4.4.1 on ubuntu linux, but can't figure out which flags are are the right ones. I realize it's architecture dependant - my machine runs w/ 32-bit Intel processor. Thanks. ...
Hello, I do some numerical computing, and I have often had problems with floating points computations when using GCC. For my current purpose, I don't care too much about the real precision of the results, but I want this firm property: no matter WHERE the SAME code is in my program, when it is run on the SAME inputs, I want it to give ...
How can you compile the VirtualDiskAPI on cygwin? I downloaded the windows version of the SDK from here, and put it in my working directory under vmdevkit. I try to compile as follows: gcc -Wall -I./vmdevkit/include -L./vmdevkit/lib -lvixDiskLib -o vmscraper vmscraper.c All my program does is include the files and call connect and dis...
Once again, I play with MinGW inline assembly. #include <stdio.h> int foobar(int); int main(){ int n = 0; printf("Number: "); scanf("%d", &n); printf("\n%d",foobar(n)); return 0; } int foobar(int num){ int result = 0; asm(".intel_syntax noprefix\n"); asm("mov eax, num\n"); asm("add eax, 110b\n"); asm("sub eax, 2\n"); as...
I m looking for a faster implementation or good a approximation of functions provided by cmath. I need to speed up the following functions pow(x,y) exp(z*pow(x,y)) where z<0. x is from (-1.0,1.0) and y is from (0.0, 5.0) ...
For some reason, I should use gcc to compile a C file, then link against Visual C++ 2008 project. (I used the current latest gcc version: cygwin gcc 4.3.4 20090804.) But there is one problem: gcc always allocate a big array with _alloca, and VC linker can't resolve the symbol __alloca. for example, int func() { int big[10240]; ...
I have many structs (classes) and standalone functions that I like to compile separately and then link to the CUDA kernel, but I am getting the "External calls are not supported" error while compiling (not linking) the kernel. nvcc forces to always use inline functions from the kernel. This is very frustrating!! If somebody have figured ...
Hey, I had a problem with the limitation of paths Here for example I run this command... : String[] cmd = new String[] {"command.com","/C", "Resource\\gcc.exe", "-E", in_path, ">", ...
class A { } class B : public A { doSomething { C * c = new C(this); } } class C { C(A* copy); } In the following example I get the following error: error: no matching function for call to `C::C(B* const)' I wan't to get the A pointer in the this call but for some reason I can't get this through. Probably so...
When a continue statement is used inside a loop in C code, GCC creates a new label with a nop instruction right before the end of the loop block and jumps to it, rather than jump to the end of the loop block itself. For instance, the following C code for (i=0; i<10; i++) { puts("blah\n"); if (i < 10) continue; puts("This sho...
I am not able to understand the following statement from the file limits.h. What is the use of this statement and what does it accomplishes? /* If we are not using GNU CC we have to define all the symbols ourself. Otherwise use gcc's definitions (see below). */ #if !defined __GNUC__ || __GNUC__ < 2 ...
I am using Ubuntu 9.10 For a particular piece of code I require GCC 3.2 but I have a higher version. Is it possible to install multiple versions and use whichever one I want to ? ...