Open System Services System Calls Reference Manual (G06.25+, H06.03+)

System Functions (n - p) pthread_sigmask(2)
STANDARDS CONFORMANCE
This function is an extension to the XPG4 Version 2 specication. Interfaces documented on this
reference page conform to the following industry standards:
IEEE Std 1003.1c-1995, POSIX System Application Program Interface
The use of the header le spthread.h is an HP exception to the POSIX standard.
527186-003 Hewlett-Packard Company 599