In most cases, syscall commands invoke the z/OS UNIX callable service that corresponds to the command verb (the first word of the command). The parameters that follow the command verb are specified in the same order as in POSIX.1 and the z/OS UNIX callable services, where applicable.

For complete information about the processing of a particular syscall command, read about the callable service it invokes, as described in z/OS UNIX System Services Programming: Assembler Callable Services Reference.