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pthread_sigmask(3)


NAME

  pthread_sigmask - Examine or change the current thread's signal mask


SYNOPSIS

  #include <pthread.h>
  #include <signal.h>

  int pthread_sigmask(
	  int how,
	  const sigset_t *set,
	  sigset_t *oset );


LIBRARY

  DECthreads POSIX 1003.1c Library (libpthread.so)


STANDARDS

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

  IEEE Std 1003.1c-1995, POSIX System Application Program Interface


PARAMETERS

  how Indicates the manner in which the set of masked signals is changed. The
      optional values are as follows:

      SIG_BLOCK
	      The resulting set is the union of the current set and the
	      signal set pointed to by the set argument.)

      SIG_UNBLOCK
	      The resulting set is the intersection of the current set and
	      the complement of the signal set pointed to by the set
	      argument.

      SIG_SETMASK
	      The resulting set is the signal set pointed to by the set
	      argument.

  set Specifies the signal set by pointing to a set of signals used to change
      the blocked set. If this set value is NULL, the how argument is ignored
      and the process signal mask is unchanged.

  oset
      Receives the value of the current signal mask (unless this value is
      NULL).


DESCRIPTION

  This routine is for UNIX systems only.

  This routine examines or changes the calling thread's signal mask.
  Typically, you use the SIG_BLOCK option for the how value to block signals
  during a critical section of code, and then use this routine's SIG_SETMASK
  option to restore the mask to the previous value returned by the previous
  call to the pthread_sigmask(3) routine.

  If there are any unblocked signals pending after a call to this routine, at
  least one of those signals is delivered before this routine returns.

  This routine does not allow the SIGKILL or SIGSTOP signals to be blocked.
  If a program attempts to block one of these signals, pthread_sigmask(3)
  gives no indication of the error.


RETURN VALUES

  If an error condition occurs, this routine returns an integer value
  indicating the type of error. Possible return values are as follows:

  0   Successful completion.

  [EINVAL]
      The value specified for how is invalid.


ERRORS

  None


SEE ALSO

  Manuals: Guide to DECthreads and Programmer's Guide

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