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cgcccalling-convention

Why does gcc ignore __attribute__((stdcall))?

When I compile the following C source with gcc version 8.1.1, I get a warning: ‘stdcall’ attribute ignored [-Wattributes].

Why does gcc choose to ignore this attribute and what can I do to make it accept it?

__attribute__((stdcall)) int S(int a) {
    return a * (a+1);
}

int main() {
    return S(6);
}
Solution

  • The gcc documentation says:

    stdcall

    On x86-32 targets, the stdcall attribute causes the compiler to assume that the called function pops off the stack space used to pass arguments, unless it takes a variable number of arguments.

    (Emphasis mine.)

    So if you're not compiling for a 32-bit machine, stdcall can't be used.