Open System Services Library Calls Reference Manual (G06.29+, H06.08+, J06.03+)

OSS Library Calls (t - v) usleep(3)
STANDARDS CONFORMANCE
The POSIX standards leave some features to the implementing vendor to define. The following
features are affected in the HP implementation:
• The SIGALRM signal does not terminate the usleep( ) function if the signal is blocked
or ignored.
• A blocked SIGALRM signal remains pending once the usleep() function returns.
• A SIGALRM signal that is not blocked or ignored causes the usleep( ) function to
return. Upon return, the signal is delivered immediately.
• A signal-catching function that interrupts the usleep( ) function can examine or change
the time in which a SIGALRM signal is generated. Such actions have no effect on the
behavior of the usleep( ) function. The newly scheduled signal is not affected by the
return from the usleep( ) function.
• The effect of a SIGALRM signal is not changed if the process exits a usleep( ) function
call by using the siglongjmp( ) or longjmp( ) function. Whether the signal is blocked
depends on the value of the signal mask when the corresponding sigsetjmp( ) function
was called.
The use of this function with the POSIX User Thread Model library conforms to the following
industry standards:
• IEEE Std 1003.1-2004, POSIX System Application Program Interface
527187-017 Hewlett-Packard Company 7−81