sigsetjmp(3P)                                       sigsetjmp(3P)



     NAME
          sigsetjmp, siglongjmp - non-local jumps

     SYNOPSIS
          #include <setjmp.h>

          int sigsetjmp(env, savemask)
          sigjmp_buf env;
          int savemask;

          void siglongjmp(env, val)
          sigjmp_buf env;
          int val;

     DESCRIPTION
          These functions are useful for dealing with errors and in-
          terrupts encountered in a low-level subroutine of a program.

          sigsetjmp saves its stack environment in env for later use
          by siglongjmp.  If the value of savemask is not zero, sig-
          setjmp also saves the process's current signal mask as part
          of the calling environment.  The environment type sigjmp_buf
          is defined in the <setjmp.h> header file.

          siglongjmp restores the environment saved by the last call
          of sigsetjmp with the corresponding env argument.  If env
          was initialized by a call to sigsetjmp with a non-zero value
          for savemask, siglongjmp also restores the saved signal
          mask.

     RETURN VALUE
          When sigsetjmp has been invoked by the calling process, zero
          is returned.

          After siglongjmp is completed, program execution continues
          as if the corresponding call of sigsetjmp (which must not
          itself have returned in the interim) had just returned the
          value val.  siglongjmp cannot cause sigsetjmp to return the
          value zero.  If val is zero, sigsetjmp returns 1.  All ac-
          cessible data have values as of the time siglongjmp was
          called.

     WARNINGS
          siglongjmp fails if env was never initialized by a call to
          sigsetjmp or when the last such call is in a function which
          has since returned.

     SEE ALSO
          sigaction(3P), sigprocmask(3P), sigsuspend(3P).






     April, 1990                                                     1