February 1998 support in Unix. These error codes are of limited use, since they only provide feedback on an immediate failure of a request. This is most likely due to invalid arguments or some general system error. A timeout errno is returned if a timer expires on the sender or receiver calls. A timeout error does not abort the request, it is merely an indication that the timer has expired.
Applications can abort a request following a timeout by closing the flow.
There is support for applications which have polling based event loops using a system call such as select. The remaining functions in the API are utility functions to ease the development of an interface which supports IPv4 and IPv6. These are documented in Appendix 1. In the future, these functions will be removed in favor of system supplied functionality. The objective of these extensions was to provide enough functionality so that applications would not need to code explicitly for either IPv4 or IPv6, or use messy compilation conditionals to develop an interface to support both address families.