How can I tell gcc not to inline a function?

c gcc inline
vehomzzz picture vehomzzz · Sep 24, 2009 · Viewed 112.9k times · Source

Say I have this small function in a source file

static void foo() {}

and I build an optimized version of my binary yet I don't want this function inlined (for optimization purposes). is there a macro I can add in a source code to prevent the inlining?

Answer

alex tingle picture alex tingle · Sep 24, 2009

You want the gcc-specific noinline attribute.

This function attribute prevents a function from being considered for inlining. If the function does not have side-effects, there are optimizations other than inlining that causes function calls to be optimized away, although the function call is live. To keep such calls from being optimized away, put asm ("");

Use it like this:

void __attribute__ ((noinline)) foo() 
{
  ...
}

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