Oct 24, 2008 · 64 #pragma is used to do something implementation-specific in C, i.e. be pragmatic for the current context rather than ideologically dogmatic. The one I regularly use is #pragma pack(1) where I'm trying to squeeze more out of my memory space on embedded solutions, with arrays of structures that would otherwise end up with 8 byte alignment.

Aug 3, 2017 · Pragma directives specify machine- or operating-specific compiler features. The __pragma keyword, which is specific to the Microsoft compiler, enables you to code pragma directives within macro definitions.

Apr 25, 2011 · Possible Duplicate: #pragma - help understanding I saw the pragma many times,but always confused, anyone knows what it does?Is it windows only?

Jul 26, 2018 · You could resolve the issue for a gcc/clang compiler by doing this: #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wformat-truncation" snprintf(dst, sizeof(dst), "%s-more", src); #pragma GCC diagnostic pop The webpage above also has a solution for Visual Studio compiler warnings.

15 #pragma is a preprocessor directive in its own right; it can't be used within a #define directive. So, this is why __pragma exists: it provides a way for a pragma to be issued from wherever the macro that uses it is expanded. This is a non-standard compiler extension (MSVC, Intel, and some C compilers support it to varying degrees).

Aug 22, 2018 · I was wondering if someone could explain to me what the #pragma pack preprocessor statement does, and more importantly, why one would want to use it. I checked out the MSDN page, which offered some

Aug 14, 2010 · #pragma comment is a compiler directive which indicates Visual C++ to leave a comment in the generated object file. The comment can then be read by the linker when it processes object files. #pragma comment(lib, libname) tells the linker to add the 'libname' library to the list of library dependencies, as if you had added it in the project properties at Linker->Input->Additional dependencies ...

Sep 24, 2010 · A pragma (from the Greek word meaning action) is used to direct the actions of the compiler in particular ways, but has no effect on the semantics of a program (in general).

Jul 27, 2023 · This works for any compiler. Use a range-based optimization pragma, a Clang extension. Write #pragma clang optimize off to disable optimizations from that point onward, and #pragma clang optimize on to reenable them. For example, simply putting #pragma clang optimize off at the top of the file will disable optimizations for the entire file.

According to wikipedia, some compilers optimize pragma once, some (like gcc) also optimize include guards. My gut says go with whatever system your code is already using. I use BOTH pragma once and guards.