UnblockSIGPIPE is a procedure defined and used on the Linux platform to re-enable the action handler for the SIGPIPE signal. UnblockSIGPIPE allows the Indy application to receive the SIGPIPE signal from a signal action handler. SIGPIPE can be raised when the active listener for a blocking socket operation has been disconnected or reset (indicated by the error number ECONNRESET).

UnblockSIGPIPE creates a signal set that includes the SIGPIPE signal number, and removes the blocking mask for the signal using sigprocmask. After calling UnblockSIGPIPE, the Indy application must then handle or ignore signals raised during execution or call BlockSIGPIPE to disable the signal action handler.