Silencing warnings inside C/XS

aufflick has asked for the wisdom of the Perl Monks concerning the following question:

Hi all,

Inside XS calls, things like calling methods with undefined values causes very loud (and usually instructive) warnings. It's not uncommon, though, for Perl APIs to have undef as a valid and useful argument - in such cases I don't want my call_method() to fill my error log with noise. I tried a naive approach of:

ENTER;
(void)call_pv("use no 'undefined';", 1);
// do some stuff with undefined values
LEAVE;
[download]

But it had no impact. Can anyone suggest how I should do this? I guess I could play with $^W but I'd rather not...

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