BSDSIGNAL(3) BSD Library Functions Manual BSDSIGNAL(3)

NAME
     bbssddssiiggnnaall - simplified signal facilities

SYNOPSIS
     ##iinncclluuddee <>

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

     or in an equivalent but easier to read typedef'd version:

     typedef void (*sigt) (int);

     sigt
     bbssddssiiggnnaall(int sig, sigt func);

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

     The function call bbssddssiiggnnaall(sig, func) has the effect as if implemented
     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:

           vvooiidd ffuunncc(int sig)

     where sig is the signal number.  The behavior is undefined if ffuunncc() is a
     function that takes more than one argument, or an argument of a different
     type.

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

EERRRROORRSS
     Refer to sigaction(2).

UUSSAAGGEE
     This function is a direct replacement for the BSD signal(3) 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 modified to use
     sigaction(2).  The bbssddssiiggnnaall() function differs from signal(3) in that
     the SARESTART flag is set and the SARESETHAND will be clear when
     bbssddssiiggnnaall() is used.  The state of these flags is not specified for
     signal(3).

SEE ALSO
     sigaction(2), sigaddset(3), sigemptyset(3), signal(3)

STANDARDS
     The bbssddssiiggnnaall() function conforms to IEEE Std 1003.1-2001 (``POSIX.1'').

BSD                            December 20, 2003                           BSD