Man Pthread_sigmask en anglais
PTHREAD_SIGMASK(P)         POSIX Programmer's Manual        PTHREAD_SIGMASK(P)



 

NAME


       pthread_sigmask, sigprocmask - examine and change blocked signals

 

SYNOPSIS


       #include 



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


       int sigprocmask(int how, const sigset_t *restrict set,
              sigset_t *restrict oset);


 

DESCRIPTION






       The  pthread_sigmask()  function  shall examine or change (or both) the
       calling thread's signal mask, regardless of the number  of  threads  in
       the process. The function shall be equivalent to sigprocmask(), without
       the restriction that the call be made in a single-threaded process.

       In a single-threaded process, the sigprocmask() function shall  examine
       or change (or both) the signal mask of the calling thread.

       If  the  argument set is not a null pointer, it points to a set of sig-
       nals to be used to change the currently blocked set.

       The argument how indicates the way in which the set is changed, and the
       application shall ensure it consists of one of the following values:

       SIG_BLOCK
              The  resulting set shall be the union of the current set and the
              signal set pointed to by set.

       SIG_SETMASK
              The resulting set shall be the signal set pointed to by set.

       SIG_UNBLOCK
              The resulting set shall be the intersection of the  current  set
              and the complement of the signal set pointed to by set.


       If  the argument oset is not a null pointer, the previous mask shall be
       stored in the location pointed to by oset.  If set is a  null  pointer,
       the  value of the argument how is not significant and the process' sig-
       nal mask shall be unchanged; thus the call can be used to enquire about
       currently blocked signals.

       If  there  are any pending unblocked signals after the call to sigproc-
       mask(), at least one of those signals shall  be  delivered  before  the
       call to sigprocmask() returns.

       It  is  not  possible  to  block those signals which cannot be ignored.
       This shall be enforced by the system without causing  an  error  to  be
       indicated.

       If  any of the SIGFPE, SIGILL, SIGSEGV, or SIGBUS signals are generated
       while they are blocked, the result is undefined, unless the signal  was
       generated  by  the  kill()  function,  the  sigqueue() function, or the
       raise() function.

       If sigprocmask() fails, the thread's signal mask shall not be  changed.

       The  use  of  the  sigprocmask()  function  is  unspecified in a multi-
       threaded process.

 

RETURN VALUE


       Upon successful completion pthread_sigmask() shall return 0; otherwise,
       it shall return the corresponding error number.

       Upon successful completion, sigprocmask() shall return 0; otherwise, -1
       shall be returned, errno shall be set to indicate the  error,  and  the
       process' signal mask shall be unchanged.

 

ERRORS


       The pthread_sigmask()  and sigprocmask() functions shall fail if:

       EINVAL The value of the how argument is not equal to one of the defined
              values.


       The pthread_sigmask() function  shall  not  return  an  error  code  of
       [EINTR].

       The following sections are informative.

 

EXAMPLES


       None.

 

APPLICATION USAGE


       None.

 

RATIONALE


       When  a  process'  signal mask is changed in a signal-catching function
       that is installed by sigaction(), the restoration of the signal mask on
       return  from  the  signal-catching  function overrides that change (see
       sigaction()). If the signal-catching function was installed  with  sig-
       nal(), it is unspecified whether this occurs.

       See  kill() for a discussion of the requirement on delivery of signals.

 

FUTURE DIRECTIONS


       None.

 

SEE ALSO


       sigaction() , sigaddset() , sigdelset() , sigemptyset() ,  sigfillset()
       ,  sigismember()  , sigpending() , sigqueue() , sigsuspend() , the Base
       Definitions volume of IEEE Std 1003.1-2001, 

 

COPYRIGHT


       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.opengroup.org/unix/online.html .



IEEE/The Open Group                  2003                   PTHREAD_SIGMASK(P)