[Queue-developers] [Fwd: Signals and 64-bit Linux]

[Werner G. K. <wer...@ya...>]

This is also potentially relevant to a Tru64 port.

James Conway <Jam...@ib...> writes:

> I am very eager to try your Queue program, but unfortunately it does
> not compile cleaning nor does the resulting executables run properly
> on my Alpha/Linux systems. The error I get is "broken-pipe" when
> invoking the example "queue -i -w -n -- hostname". In checking the
> compiler output I see several warnings about "overflow in implicit
> constant conversion" in "handle.c". These map to the functions
> "sigmask" and "sigsetmask", and I note that the man pages state:
>      This interface is made obsolete by sigprocmask(2).
>
> Further, the system include file "signal.h" has this to say about
> sigmask,sigsetmask, siggetmask, and sigblock:
>
> /* None of the following functions should be used anymore.  They are here
>     only for compatibility.  A single word (`int') is not guaranteed to be
>     enough to hold a complete signal mask and therefore these functions
>     simply do not work in many situations.  Use `sigprocmask' instead.  */
>
> The code that generates the compiler warnings is as follows:
>   line  350:  sigsetmask(~sigmask(SIGCHLD));
>   line 1151:
> sigsetmask(~(sigmask(SIGCHLD)|sigmask(SIGUSR1)|sigmask(SIGUSR2)|sigmask(SIGCONT)|sigmask(SIGTERM)));
> I suspect that the "~" is the problem.
>
> Unfortunately I have no experience with the signal facility. The
> recommended sigprocmask replacement is not straightforward to use. Do
> you have any comments on this?
>
> I have also (and so far!) found two lines that require minor fixes
> for my environment. These may be quite general however.
>
> ident.c, line 82:
>    oldsignal = signal(SIGALRM, do_nothing2);
> The gcc compiler warns about the function do_nothing2. Prepending a
> "&" fixes it:
>    oldsignal = signal(SIGALRM, &do_nothing2);
>
> ident.c. line 121:
>      signal(alarm, oldsignal);
> The gcc compiler warns about arg 1, and I presume a call to the
> "alarm" function is intended. If so, then the following would seem to
> be OK:
>      signal(alarm(0), oldsignal);
>
> Finally, I would prefer to use the Compaq compilers in favor of the
> GNU cc and c++. I cannot find a way to do this easily. The
> documentation suggests that this would work:
>     env CC=ccc ./configure
> where "ccc" is the Compaq C compiler. However, gcc remains in effect.
> Am I on the wrong track?
>
> As background, the machines are Alpha XP1000 workstations running
> RedHat Linux 6.2.
>
> Thank you for your help.
>
> James Conway
> --
> ----------------------------------------------------------------------
> James Conway, PhD.,
> Laboratoire de Microscopie Electronique Structurale
> Institut de Biologie Structurale
> 41 rue Jules Horowitz
> 38027 Grenoble Cedex 1
> FRANCE
> Email:     Jam...@ib...
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