gtpi1m4l | System Installation Support Reference |
The select TCP/IP support user exit, USOK, allows you to select either
TCP/IP offload support or TCP/IP native stack support for a given
socket.
USOK is called only when all of the following conditions are true:
- Both TCP/IP offload support and TCP/IP native stack support are defined in
the TPF system.
- A socket function call is issued.
USOK is called in segment C536.
Input
- applname
- A character string pointer to the name of the application that issued the
socket function.
Programming Considerations
- IBM provides sample code for USOK, that selects offload support for all
socket function requests.
- All entry control block (ECB) fields and data levels must be returned to
the caller in the same state they were on entry.
- USOK is a subsystem-unique dynamic load module (DLM).
- The value returned by USOK, indicating the type of TCP/IP support,
determines how subsequent gethostid and gethostname
functions are processed for this ECB. See TPF
Transmission Control Protocol/Internet Protocol for more information
about the gethostid and gethostname functions.
- If the value of applname is CLTX, INETD is creating the
socket. The server program defined to INETD that is being started is
contained in EBX000-EBX003.
Return Values
USOK returns one of the following values:
- 0
- Use TCP/IP offload support.
- 1
- Use TCP/IP native stack support.