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- Use of #pragma in C - Stack Overflow
#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
- Difference between #pragma and _Pragma () in C - Stack Overflow
has the same effect as #pragma GCC dependency "parse y" The same effect could be achieved using macros, for example #define DO_PRAGMA(x) _Pragma (#x) DO_PRAGMA (GCC dependency "parse y") According to IBM tutorial: The _Pragma operator is an alternative method of specifying #pragma directives For example, the following two statements are
- What does #pragma once mean in C? - Stack Overflow
In this case, #pragma once's purpose is to replace the include guards that you use in header files to avoid multiple inclusion It works a little faster on the compilers that support it, so it may reduce the compilation time on large projects with a lot of header files that are #include 'ed frequently
- c - Utilidade do #pragma - Stack Overflow em Português
O pragma "once" normalmente (sempre ?) é utilizado no início de um arquivo h que vai ser incluído em outros arquivos fonte c ou cpp (ou mesmo outros h) Este pragma instrui o compilador a ler este arquivo apenas uma vez, mesmo que o fluxo de compilação de um fonte implique sua leitura mais de uma vez
- What is __pragma and what are the differences between __pragma and #pragma
#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)
- c - #pragma pack effect - Stack Overflow
#pragma allows you to override this to achieve more efficient space usage, at the expense of access speed, or for consistency of stored data between different compiler targets I had a lot of fun with this transitioning from 16 bit to 32 bit code; I expect porting to 64 bit code will cause the same kinds of headaches for some code
- Whats difference between #pragma and #ifndef? [duplicate]
Use of any #pragma that is not defined in the C (or C++) standard renders your code non-portable #pragma once is a bit of an exception in that it is one of the most commonly-implemented of the non-standard #pragma constructs Its implementation, however, is not universal across standards-compliant compilers #ifndef is
- c++ - What does #pragma comment mean? - Stack Overflow
#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 The comment can then be read by the linker when it processes object files
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