static inline void vect_abs(float *srcdst, int n)
{
while (n-- > 0)
*(srcdst++) = fabsf( (*srcdst) );
}
Why is this code giving the warning: operation on ‘srcdst’ may be undefined [-Wsequence-point]?
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Danijel
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2Read up on sequence points. – Hatted Rooster Mar 17 '21 at 14:25
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1`=` operator doesn't introduce a sequence point; you're reading & writing to the same object without an intervening sequence point. – P.P Mar 17 '21 at 14:27
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What value you are expecting `srcdst` to be when calling `fabsf( (*srcdst) );` ? The previous one or the incremented one? – Eugene Sh. Mar 17 '21 at 14:27
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OK, first `*srcdst = fabsf( *srcdst );`, then `srcdst++;`. – Danijel Mar 17 '21 at 14:31
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I think the canonical question on this topic is https://stackoverflow.com/questions/949433/why-are-these-constructs-using-pre-and-post-increment-undefined-behavior?noredirect=1&lq=1 – Nate Eldredge Mar 17 '21 at 16:59
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Thanks @NateEldredge, agree, that should be the one. – Danijel Mar 18 '21 at 06:45