bsd_signal(3C)                                               bsd_signal(3C)

NAME
     bsdsignal - simplified signal facilities

SYNOPSIS
     #include <signal.h>

     void (*bsdsignal(int sig, void (*func)(int)))(int);

DESCRIPTION
     The bsdsignal() function provides a partially compatible interface
     for programs written to historical system interfaces (see APPLICATION
     USAGE below).

     The function call bsdsignal(sig, func) has an effect as if imple-
     mented as:

     void (*bsdsignal(int sig, void (*func)(int)))(int)
     {
          struct sigaction act, oact;

          act.sahandler = func;
          act.saflags = SARESTART;
          sigemptyset(&act.samask);
          sigaddset(&act.samask, sig);
          if (sigaction(sig, &act, &oact) == -1)
               return(SIGERR);
          return(oact.sahandler);
     }

     The handler function should be declared:

     void handler(int sig);

     where sig is the signal number. The behavior is undefined if func is a
     function that takes more than one argument, or an argument of a dif-
     ferent type.

RETURN VALUE
     Upon successful completion, bsdsignal() returns the previous action
     for sig. Otherwise, SIGERR is returned and errno is set to indicate
     the error.

ERRORS
     Refer to sigaction(2).

APPLICATION USAGE
     This function is a direct replacement for the BSD signal() function
     for simple applications that are installing a single-argument signal
     handler function. If a BSD signal handler function is being installed
     that expects more than one argument, the application has to be modi-
     fied to use sigaction(). The bsdsignal() function differs from sig-
     nal() in that the SARESTART flag is set and the SARESETHAND will be



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bsd_signal(3C)                                               bsd_signal(3C)

     clear when bsdsignal() is used. The state of these flags is not
     specified for signal().

SEE ALSO
     sigaction(2), signal(3-ucb), sigaddset(3C), sigemptyset(3C), sig-
     nal(5).
















































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