Re: [PATCH] manual: Add note to process.texi about MT-process fork (Bug 30159)

[Florian Weimer <fweimer@redhat.com>]

* Carlos O'Donell via Libc-alpha:

> The forked child of an MT-process may only call AS-safe functions.
> ---
>  manual/process.texi | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/manual/process.texi b/manual/process.texi
> index 9307379194..dfdf0923b4 100644
> --- a/manual/process.texi
> +++ b/manual/process.texi
> @@ -316,6 +316,12 @@ The child doesn't inherit alarms set by the parent process.
>  The set of pending signals (@pxref{Delivery of Signal}) for the child
>  process is cleared.  (The child process inherits its mask of blocked
>  signals and signal actions from the parent process.)
> +
> +@item
> +In the case of a multi-threaded parent, the child process may only
> +safely call asynchronous-signal-safe functions until the process is
> +replaced with a call to an @code{exec} family function.

We support calling malloc after fork as an extension.  For example,
calling opendir after fork to find file descriptors in /proc/self/fd is
fairly common.

Perhaps add:

As an extension relative to POSIX, @theglibc{} supports calling
@code{malloc} and other allocation functions after @code{fork}.  This
only applies to the standard @code{malloc}.  Whether this extension is
supported by replacement @code{malloc} implementations depends on the
replacement.  @xref{Replacing malloc}.

Thanks,
Florian