where can i find the header of __sync_add_and_fetch

Question

can any one tell me where can I find the header for __sync_add_and_fetch built in function
with out header how could we able to compile the code .

Why do you think you need it? Both C and C++ have Standard alternatives (but as they're two languages that forked decades ago, the alternative to use depends on the language you're actually using.) — MSalters, Jul 19 '16 at 09:41

score 6 · Accepted Answer · answered Jul 19 '16 at 05:59

It is a built-in function, meaning the compiler KNOWS this function, and it doesn't have (to have) a header file.

In clang, it is part of Builtins.def here: https://github.com/llvm-mirror/clang/blob/master/include/clang/Basic/Builtins.def#L524

and codegen here: https://github.com/llvm-mirror/clang/blob/master/lib/CodeGen/CGBuiltin.cpp#L1204

Other compilers will have some similar concepts in declaring "builtin functions".

Of course, not all compilers support atomic builtins, so if you are seeing an error saying "__sync_add_and_fetch is not a function", it may be because the compiler doesn't have that function - it may be called something else in that compiler, or it may simply not exist, depending on what compiler it is.

where can i find the header of __sync_add_and_fetch

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