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sigsuspend(2)
NAME
  sigsuspend - Atomically changes the set of blocked signals and waits for a
  signal

LIBRARY
  Standard C Library (libc.so, libc.a)

SYNOPSIS
  #include <signal.h>

  int sigsuspend (
	  const sigset_t *signal_mask );

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  sigsuspend():	 XPG4, XPG4-UNIX

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  signal_mask
	    Points to a set of signals.

DESCRIPTION
  The sigsuspend() function replaces the signal mask of the process (or
  thread) with the set of signals pointed to by the signal_mask parameter,
  and then suspends execution of the caller until delivery of a signal whose
  action is either to execute a signal-catching function or to terminate the
  process.  The sigsuspend() function does not allow the SIGKILL or SIGSTOP
  signals to be blocked.  If a program attempts to block one of these
  signals, the sigsuspend() function gives no indication of the error; the
  illegal request is simply ignored.

  If delivery of a signal causes the process to terminate, the sigsuspend()
  function does not return. If delivery of a signal causes a signal-catching
  function to execute, the sigsuspend() function returns after the signal-
  catching function returns, with the signal mask restored to the set that
  existed prior to the call to the sigsuspend() function.

  The sigsuspend() function sets the signal mask and waits for an unblocked
  signal as one atomic operation. This means that signals cannot occur
  between the operations of setting the mask and waiting for a signal.	If a
  program invokes sigprocmask(SIG_SETMASK) and sigpause() separately, a
  signal that occurs between these functions might not be noticed by
  sigpause().

  In normal usage, a signal is blocked by using the
  sigprocmask(SIG_BLOCK,...) or pthread_sigmask(...) function at the
  beginning of a critical section. The process then determines whether there
  is work for it to do. If no work is to be done, the process waits for work
  by calling the sigsuspend() function with the mask previously returned by
  the sigprocmask() function.

NOTES
  The sigpause() function is provided for compatibility with older UNIX
  systems; its function is a subset of the sigsuspend() function.

RETURN VALUES
  Since the sigsuspend() function suspends process execution indefinitely,
  there is no successful completion return value.  If a return occurs, -1 is
  returned and errno is set to indicate the error.

ERRORS
  The sigsuspend() function sets errno to the specified values for the
  following conditions:

  [EINTR]   A signal is caught by the calling process and control is returned
	    from the signal-catching function.

RELATED INFORMATION
  Functions: pause(3), sigaction(2), sigblock(2), sigprocmask(2), sigvec(2)

  Standards: standards(5)

Index for Section 2

Alphabetical listing for S

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