SIGALRM

SIGALRM

Real-Time Expiration

Default handling
Ignoring the signal
Information returned by siginfo
USS Considerations

SIGALRM is an asynchronous signal. The SIGALRM signal is raised when a time interval specified in a call to the alarm or alarmd function expires.

Because SIGALRM is an asynchronous signal, the SAS/C library discovers the signal only when you call a function, when a function returns, or when you issue a call to sigchk . For this reason and because of inaccuracies and overhead in operating system timing functions, you can consider the time interval requested by alarm a lower bound; the handler may not be invoked immediately after the interval expires.

Default handling

By default, SIGALRM causes the program to abnormally terminate with a user ABEND code of 1225.

Ignoring the signal

It is possible, but not particularly useful, to ignore SIGALRM .

Information returned by siginfo

When siginfo is called in a handler for SIGALRM , it returns NULL .

USS Considerations

If SIGALRM is managed by USS, the SAS/C alarmd and sleepd functions are not available. If the SAS/C library manages SIGALRM , the ps shell command will not accurately indicate when the process is sleeping.

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