Re: blocking file lock functions (lockf,flock,fcntl) do not return after timer signal

[Michael Kerrisk]

> >> Also, using a 'C' runtime library call like write() in a signal-
> >> handler is a bug.
> >
> > But this is not correct.  write() is async-signal-safe (POSIX
> > requires it).
> 
> Then tell it to the doom-sayers who always excoriate me when
> I use a 'C' runtime library call in test signal code. I have
> been told that the __only__ thing you can do in a signal handler
> is access global memory and/or execute siglongjmp().

Nevertheless, it is not so.  The problem that some may 
complain about is not C RTL code, but perhaps using 
printf() (wrong) instead of write()


From:
http://www.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_04.html#tag_02_04

    The following table defines a set of functions that shall 
    be either reentrant or non-interruptible by signals and 
    shall be async-signal-safe. Therefore applications may 
    invoke them, without restriction, from signal-catching 
    functions:
    [...]
    write()

Cheers,

Michael

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