BPX4FTR (ftruncate) example

The following code truncates the file described by FILEDESC after 512 bytes. For the callable service, see ftruncate (BPX1FTR, BPX4FTR) — Change the size of a file. AMODE 31 callers use BPX1FTR (ftruncate) example.

                                              
       MVC   FILEDESC,..           File descriptor from open            
         MVC   NEWLEN(8),=FL8'512'                                      
         SPACE ,                                                        
         CALL  BPX4FTR,              Truncate a file                   +
               (FILEDESC,            Input: File descriptor            +
               NEWLEN,               Input: Length to keep             +
               RETVAL,               Return value: 0 or -1             +
               RETCODE,              Return code                       +
               RSNCODE),             Reason code                       +
               MF=(E,PLIST)          ----------------------------------