sigrelse() -- System Call (libc)

Release a signal for processing
#include <signal.h>
int sigrelse (sigtype)
int sigtype;

sigrelse() is  a member  of the  sigset() family of  signal-handling system
calls.  It releases the  signal sigtype, which had previously been ``placed
on hold'' by the system call sighold(). Only one ``copy'' of sigtype can be
held  at a  time.  Thus,  you  can use  sighold() and  sigrelse() to  defer
processing of the signal sigtype. This  permits you to protect a portion of
your application from this signal until it is ready to process it.

When sigtype is released, it is  processed by the function that had set for
it  by the  system call  sigset().  If sigset()  has not  been invoked  for
sigtype,  then  the  system uses  the  function  to  which SIG_DFL  points.
SIG_DFL terminates  the process, just as if it  called the function exit().
In addition,  it dumps core  if sigtype is  any of the  following: SIGQUIT,
SIGRESET, SIGTRAP, SIGSEGV, or SIGSYS.

Note  that  signal SIGKILL  cannot  be  held.  See  the  Lexicon entry  for
signal() for a list of recognized signals.

sigrelse()  returns zero  if all  went well.  If  something went  wrong, it
returns -1 and sets errno to an appropriate value.

See Also

libc,
sighold(),
sigignore(),
signal(),
sigpause(),
sigset()

Notes

For  more information  on  the sigset()  family  of signal-handling  system
calls, see the Lexicon entry for sigset().

© 2012 by Stephen A. Ness