BPX1SWT (sigwait) example

The following code waits for an asynchronous signal, SIGALRM bit 14 in the mask. For the callable service, see sigwait (BPX1SWT, BPX4SWT) — Wait for a signal. For the data structure, see BPXYSIGH — Signal constants. AMODE 64 callers use BPX4SWT (sigwait) example.
                                              
         MVC   WAITMASK(8),=XL8'000400000000000000'                     
         SPACE ,                                                        
         CALL  BPX1SWT,              Wait for asynchronous signal      +
               (WAITMASK,            Input: Signal mask SIGALRM        +
               RETVAL,               Return value: 0 or -1             +
               RETCODE,              Return code                       +
               RSNCODE),             Reason code                       +
               VL,MF=(E,PLIST)       ----------------------------------