Hence, I attribute their absence to "the magic of XS".

With the test2() sub, the compiler sees it is *inevitable* that the conversion from IV/UV to double will occur - and warns accordingly.

With the test() sub, that inevitability does not exist (as there's the possibility that SvNSIV() defines an NV), and the compiler recognises this. Therefore the warning cannot be given.

For example, with this modification, the warning disappears: 
#define IIII(sv) (SvIOK(sv) ? SvIV(sv) : SvNV(sv))
#define UUUU(sv) (SvUOK(sv) ? SvUV(sv) : SvNV(sv))

void test2 ( SV *sv ) {
    double d = IIII( sv );
    double d2 = UUUU( sv );
    return;
}

[download]
Cheers,
Rob

In reply to Re^8: perl inline::c sorting problem (implicit coercion) by syphilis
in thread perl inline::c sorting problem by dalittle

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