The following environmental restrictions and programming requirements apply to the Callable Socket API:

• SRB mode

  This API can be invoked only in TCB mode (task mode).

• Cross-memory mode

  This API can be invoked only in a non-cross-memory environment (PASN=SASN=HASN).

• Functional Recovery Routine (FRR)

  Do not invoke this API with an FRR set. This causes system recovery routines to be bypassed and severely damage the system.

• Locks

  No locks should be held when issuing this call.

• INITAPI, INITAPIX, and TERMAPI calls

  The INITAPI, INITAPIX, and TERMAPI calls must be issued under the same task.

• Storage

  Storage acquired for the purpose of containing data returned from a socket call must be obtained in the same key as the application program status word (PSW) at the time of the socket call.

• Nested socket API calls

  You cannot issue "nested" API calls within the same task. That is, if a request block (RB) issues a socket API call and is interrupted by an interrupt request block (IRB) in an STIMER exit, any additional socket API calls that the IRB attempts to issue are detected and flagged as an error.