Checklist #3: Writing An Exec That Sets Up Allocation To Sysexec - IBM TSO/E REXX User Manual

2. Edit a member of the newly created PDS by selecting the ISPF/PDF EDIT

Checklist #3: Writing an Exec that Sets up Allocation to SYSEXEC

1. Write an exec named SETUP that allocates data sets to SYSEXEC.
2. Execute SETUP by entering the following EXEC command:
ALLOCATE DA(rexx.exec) NEW DIR(10) SPACE(50,20) DSORG(po)
RECFM(v,b) LRECL(255) BLKSIZE(6120)
For more information about the ALLOCATE command, see z/OS TSO/E REXX
User's Guide and z/OS TSO/E Command Reference.
option (option 2) and specifying the PDS name with a member name.
See the description for this step in the previous checklist #4 on page 189.
Create a data set member named SETUP in your exec PDS. In SETUP issue
an ALLOCATE command that concatenates your PDS to the beginning of all the
data sets already allocated to SYSEXEC. Include the data sets allocated to
SYSEXEC from the list in the "Preliminary Checklist" on page 186. If there are
no other data sets allocated to SYSEXEC, specify your PDS only. Your SETUP
exec could look like the following example.
Sample SETUP Exec
/****************************** REXX *******************************/
/* This exec is an example of how to allocate a private PDS named */
/* USERID.REXX.EXEC to the beginning of a concatenation to SYSEXEC */
/* that consists of one other data set named 'ISP.PHONE.EXEC'. To */
/* make sure that SYSEXEC is available, the exec issues EXECUTIL
/* SEARCHDD(yes) command. After the ALLOCATE command executes, a */
/* message indicates whether the command was successful or not.
/*******************************************************************/
"EXECUTIL SEARCHDD(yes)"
"ALLOC FILE(SYSEXEC) DATASET(rexx.exec,",
"'isp.phone.exec') SHR REUSE"
IF RC = 0 THEN
SAY 'Allocation to SYSEXEC completed.'
ELSE
SAY 'Allocation to SYSEXEC failed.'
Note: The order in which you list data sets in an ALLOCATE command is the
order in which they are concatenated and searched. To give your execs
priority in the search order, list your data set of execs before other data
sets.
Generally all the data sets in the list should have the same record format
(either RECFM=VB or RECFM=FB) and logical record length, LRECL.
Also, the first data set in the list can determine the block size, BLKSIZE,
for the data sets that follow. If the block size of the first data set is
smaller than the block sizes of subsequent data sets, you might end in
error. To avoid error, use the Preliminary Checklist and the other
checklists provided, and follow directions carefully.
READY
EXEC rexx.exec(setup) exec
If the allocation was successful, you should then see displayed on your screen:
/* to ensure that SYSEXEC is available*/
Appendix A. Allocating Data Sets
Checklist #2
*/
*/
191