That pragma is used to link against the specified .lib file. This is an alternative to specifying the library in the external dependencies field in project settings. Mostly, it’s used to support different versions: #ifdef USE_FIRST_VERSION #pragma comment(lib, “vers1.lib”) #else #pragma comment(lib, “vers2.lib”) #endif When your application uses a dynamically-linked library, a lib file tells … Read more
I’ve run into this annoyance, too. According to the GCC manpage -Wall turns on -Wunknown-pragmas for you, so just manually disable it using -Wno-unknown-pragmas after -Wall. There is a GCC feature request to make this work using #pragma GCC diagnostic: C++ preprocessor ignores #pragma GCC diagnostic
#pragma once should be placed before any headers are included. Argument of #pragma directive is a subject to macro expansion. So content of included headers can alter the pragma behavior: // whatever.hpp … #define once lol_no // your_header.hpp #include “whatever.hpp” #pragma once // warning C4068: unknown pragma
It depends on how much portable your program is expected to be. As long as you are writing a program which is supposed to work with compilers which you know definitely support #prama once, just using #pragma once should suffice. But doing so you restrict your program to set of compilers which support the implementation … Read more
This appears to be a bug in gcc at least. The following code: #pragma GCC diagnostic ignored “-Wunknown-pragmas” #pragma GCC diagnostic ignored “-Wuninitialized” int fn(void) { #pragma xyzzy int x; return x; } int main (void) { return fn(); } has no problems ignoring the uninitialised x value but still complains about the pragma (without … Read more
At the very least you should be specific about which warnings you’ve deliberately chosen to ignore. That way, if later maintenance introduces a ‘new’ warning/issue that you should be made aware of, the warning about the newly-introduced error won’t be suppressed by your blanket pragma warning disable directive. You can get the warning numbers pertaining … Read more
Here is one that allows you to click on the output pane: (There are also some other nice tips there) http://www.highprogrammer.com/alan/windev/visualstudio.html // Statements like: // #pragma message(Reminder “Fix this problem!”) // Which will cause messages like: // C:\Source\Project\main.cpp(47): Reminder: Fix this problem! // to show up during compiles. Note that you can NOT use the … Read more
You can push/pop a low level of warning, like this: #pragma warning(push, 0) #include <boost/bind.hpp> #include <boost/shared_ptr.hpp> // … #pragma warning(pop) But know that it’s not possible to disable all warnings. For example, some linker warnings are impossible to turn off.
No. It means you have called a CUDA kernel with one block and that one block has 100 active threads. You’re passing size as the second function parameter to your kernel. In your kernel each of those 100 threads executes the for loop 100 times. #pragma unroll is a compiler optimization that can, for example, … Read more