HP 3000 Manuals HP 3000 Manuals
sigprocmask
Examines or changes blocked signals.
Syntax
#include <signal.h>
int sigprocmask (int how, const sigset_t *set,
sigset_t *oset);
Parameters
how Indicates how the process's signal mask should be changed by
the parameter set. One only of the following values must be
passed:
SIG_BLOCK Add the specified signals in set to the
process's signal mask.
SIG_UNBLOCK Delete the specified signals in set from the
process's signal mask.
SIG_SETMASK Replace the process's signal mask with the
signal mask pointed to by set.
set If not NULL, a pointer to a structure of type sigset_t
containing a set of signals to use when changing the calling
process's signal mask in the manner defined by how. If NULL,
how is ignored and the process's signal mask remains
unchanged.
oset If not NULL, a pointer to a structure of sigset_t that returns
the process's previous signal mask (prior to any changes). If
NULL, the current signal mask is not returned.
Return Values
0 Success.
-1 An error occurred. The process's signal mask is not changed,
and errno is set to indicate the error condition.
Description
The sigprocmask() function allows the caller to examine or change (or
both) the calling process's signal mask. If any pending unblocked
signals remain after a call to sigprocmask(), at least one of those
signals is delivered to the calling process before the function returns.
It is not possible to block the signals SIGKILL and SIGSTOP. If specified
in the structure pointed to by set, they are removed by the system
without error.
Implementation Considerations
Refer to the EFAULT error description below.
Refer to Table 3-5 for implementation considerations associated with
signals.
Errors
If an error occurs, errno is set to one of the following values:
EFAULT CAUSE The system detected a bad address in attempting to
use the set or oset parameters.
ACTION Make sure that the pointer is correctly initialized.
EINVAL CAUSE The value of how is not valid.
ACTION Specify valid values for how.
See Also
sigaction(), sigpending(), sigsuspend(), <signal.h>, POSIX.1 (Section
3.3.5)