[musl] The `sigpause` function behavior does not fully comply with the POSIX specification

[musl] The `sigpause` function behavior does not fully comply with the POSIX specification

[Tommy]

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Hello:
I noticed this commit.
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https://git.musl-libc.org/cgit/musl/commit/src/signal/sigpause.c?id=06c5e4e832f4796be02c743270fb554f978de02c

This commit changed the behavior of `sigpause`. When I passed an invalid
`sig` value, the `sigdelset` function returned -1 and set the error code to
EINVAL, which caused `sigpause` to return -1 and set the error code to
EINVAL. In the POSIX specification, `sigpause` can only return -1 if it
returns, and set the error code to `EINTR` (see
https://man7.org/linux/man-pages/man3/sigpause.3.html#RETURN_VALUE). Maybe
the current behavior of the `sigpause` function violates the POSIX
specification, so I would like to ask if this is a bug.

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Re: [musl] Re: The `sigpause` function behavior does not fully comply with the POSIX specification

[Thorsten Glaser]

On Mon, 9 Jun 2025, Valery Ushakov wrote:

>sigpause is a 4.3BSD interface and it used to be a system call that
>did this:

The thing you missed is that there were two mututally incompatible
sigpause functions around.

The 4.3BSD one is obsolete, but still present in BSD libcs, and
merely resolves to:

	int
	sigpause(int mask)
	{
		return (sigsuspend((sigset_t *)&mask));
	}

The incompatible *other* one got standardised for UNIX95 and is
the one removed from latest POSIX. I’d even say drop it the next
time musl bumps the major version anyway.

bye,
//mirabilos
-- 
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