Adds a signal to a signal set.
Syntax |
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#include <signal.h>
int sigaddset (sigset_t *set, int sig);
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Parameters |
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- set
A pointer to a structure of type sigset_t containing a set of signals to which sig is to be added.
- sig
The signal number of the signal to add to set. Valid signals are described in Table 3-6 “POSIX/iX Signals”.
Return Values |
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- 0
Success.
- -1
An error occurred. The signal is not added, and errno is set to indicate the error condition.
Description |
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The sigaddset() function adds the signal sig to the set of signals specified in the structure pointed to by set.
The structure of type sigset_t pointed to by set must be initialized by sigemptyset() or sigfillset() prior to being used by sigaddset(); otherwise, the results are undefined.
Implementation Considerations |
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Refer to the EFAULT error description below.
Errors |
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If an error occurs, errno is set to one of the following values:
| EFAULT | CAUSE
| The system detected a NULL or bad address in attempting to use
the set parameter. |
| | ACTION
| Make sure that the pointer is correctly initialized.
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| EINVAL | CAUSE
| The signal sig is not a valid signal number. |
| | ACTION
| Refer to Table 3-6 “POSIX/iX Signals” for descriptions of valid signal numbers.
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See Also |
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sigaction(), sigdelset(), sigemptyset(), sigfillset(), sigismember(), <signal.h>, POSIX.1 (Section 3.3.3)
