Return_code

The Return_code parameter is referred to as the errno in the POSIX and X/Open C interfaces. The Return_code is returned only if the service fails.

In the callable service descriptions, some of the possible return codes are listed for services that have return codes. The return codes are described in each service if they help to describe its function.

For each return code, any reason code that may accompany it is identified.

The return codes and their descriptions can be found in z/OS UNIX System Services Messages and Codes.

Some Return_code values may occur for any callable service: the return codes that are unique to z/OS UNIX. They are not always listed under each callable service. See z/OS UNIX System Services Messages and Codes for a description of these return codes.

The following five return codes can occur with any callable service, and are not listed with each service because the failure may occur before the syscall gets control:

Return_code	Explanation
EFAULT	An address is incorrect, usually because it is a zero pointer, an uninitialized pointer, or a pointer to read-only storage (for example, a program constant of zero) for a parameter that is (or could be, in a different context) an output parameter.
EMVSINITIAL	A process initialization error has occurred.
EMVSERR	An MVS™ environmental or internal error has occurred.
EMVSPARM	Bad parameters were passed to the service.
ENOMEM	Not enough space is available to fill the request.