BPX1OPN (open) example

The following code opens file usr/inv/nov.d with user read-write, group read and other read. A file descriptor (FILEDESC) is returned. For the callable service, see open (BPX1OPN, BPX4OPN) — Open a file. For the data structure, see BPXYOPNF — Map flag values for open, AMODE 64 callers use BPX4OPN (open) example. BPXYMODE — Map the mode constants of the file services, and BPXYFTYP — File type definitions.

                                              
         MVC   BUFFERA(13),=CL13'usr/inv/nov.d'                         
         MVC   BUFLENA,=F'13'                                           
         XC    S_MODE,S_MODE                                            
         MVI   S_MODE2,S_IRUSR       User read/write, group read,       
         MVI   S_MODE3,S_IWUSR+S_IRGRP+S_IROTH           other read     
         XC    O_FLAGS(OPNF#LENGTH),O_FLAGS                             
         MVI   O_FLAGS4,O_CREAT+O_RDWR Create, open for read and write  
         SPACE ,                                                        
         CALL  BPX1OPN,              Open a file                       +
               (BUFLENA,             Input: Pathname length            +
               BUFFERA,              Input: Pathname                   +
               O_FLAGS,              Input: Access            BPXYOPNF +
               S_MODE,               Input: Mode    BPXYMODE, BPXYFTYP +
               RETVAL,               Return value:-1 or file descriptor+
               RETCODE,              Return code                       +
               RSNCODE),             Reason code                       +
               VL,MF=(E,PLIST)       ---------------------------------- 
         ICM   R15,B'1111',RETVAL    Test RETVAL                        
         BL    PSEUDO                Branch if negative (-1 = failure)  
         ST    R15,FILEDESC          Store the file descriptor