HP-UX Reference (11i v2 03/08) - 2 System Calls (vol 5)

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sigblock(2) sigblock(2)

(TO BE OBSOLETED)

NAME

sigblock - block signals

SYNOPSIS

#include <signal.h>

long sigblock(long mask);

DESCRIPTION

sigblock() causes the signals speciﬁed in mask to be added to the set of signals currently being

blocked from delivery. Signal i is blocked if the i-th bit in mask is

1, as speciﬁed with the macro

sigmask(i).

It is not possible to block signals that cannot be ignored, as documented in signal (5); this restriction is

silently imposed by the system.

Use

sigsetmask() to set the mask absolutely (see sigsetmask (2)).

RETURN VALUE

sigblock() returns the previous set of masked signals.

EXAMPLES

The following call to

sigblock() adds the SIGUSR1 and SIGUSR2 signals to the mask of signals

currently blocked for the process:

long oldmask;

oldmask = sigblock (sigmask (SIGUSR1) | sigmask (SIGUSR2));

WARNINGS

Do not use sigblock() in conjunction with the facilities described under sigset (3C).

Obsolescent Interfaces

sigblock() is to be obsoleted at a future date.

APPLICATION USAGE

Threads Considerations

Since each thread maintains its own blocked signal mask,

sigblock() modiﬁes only the calling

thread’s blocked signal mask.

For more information regarding signals and threads, refer to signal (5).

LP64 Programs

sigblock() accepts and returns long (64 bit) values. However, as for ILP32 programs, sigblock()

supports signals numbered 1 through 32. The upper 32 bits of the mask argument are ignored. Also, the

upper 32 bits of the returned mask have no meaning.

AUTHOR

sigblock() was developed by the University of California, Berkeley.