On Mon, 18 Sep 2017, Niels Möller wrote: > Andreas Schwab <sch...@suse.de> writes: > > > The problem is that assert is not allowed to evaluate the expression > > with -DNDEBUG, and side effects must not be carried out. > > I'm suggesting that with -DNDEBUG, assert(x) should let the compiler > assume that x is true, but without producing any code to evaluate it at > runtime.
There's no requirement that x is even a valid expression with -DNDEBUG. Consider code that does int x; #ifndef NDEBUG int other_variable_used_in_assertion = something (); #endif /* ... */ assert (other_variable_used_in_assertion == x); where it is completely valid in ISO C not to have the NDEBUG conditional around the assert call, because in the NDEBUG case the macro argument won't be expanded. -- Joseph S. Myers jos...@codesourcery.com
