Setting $! in xs

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

Hi - How do I set $! in an xs method? My reading of perlxstut, perlxs, and perlguts leads me to believe it's tied in with error and _sys_errlist; but I want to set $! to a meaningful string for my module.

Thanks - this is my first post ;-)

Comment on Setting $! in xs

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Re: Setting $! in xs by Prof Vince (Friar) on Aug 06, 2011 at 20:48 UTC
Just assign to errno in your C code. $! is magic, so it will be automatically updated the next time it is evaluated in Perl. But you should do that only if the error code you want to pass this way is a meaningful errno code (for example, if it is given after a system call). For all the other cases, an exception is a much saner solution.	[reply]
Re: Setting $! in xs by Anonymous Monk on Aug 06, 2011 at 14:35 UTC
Don't, that is not the purpose of $!, simply croak instead	[reply]
Re^2: Setting $! in xs by Anonymous Monk on Aug 06, 2011 at 14:38 UTC
Well, if you still wanted to, you could `sv_setpvf( get_sv("!", TRUE), "blah %d %s", errno, strerror(errno) );` [download]	[reply] [d/l]
Re: Setting $! in xs by strredwolf (Chaplain) on Aug 06, 2011 at 17:33 UTC
Wouldn't $? be better off, or setting an internal error that your XS would provide access to? Information doesn't want to be free. It wants to be feline.	[reply]
Re: Setting $! in xs by Vitantonio (Initiate) on Aug 07, 2011 at 06:33 UTC
Thanks all... I guess I was trying to get too clever, I'll build my method to return a meaningfull error string.	[reply]