Replacing an Existing Exit

The following shows SMP/E system modification statements. Follow these steps to replace a module which was supplied by IBM or by the installation.

Figure 1. Replacing an Existing Exit

++USERMOD(changename)   /* Replacement of existing module */     
  .
++VER(Z038) FMID(fmid) PRE(xxxxxxx) SUP(yyyyyyy)                 
  .
++SRC(modname) SYSLIB(SUSERLIB) DISTLIB(ASRCLIB)                 
  .

Explanation of Figure 1:

Replace changename with a name to identify the system change. For example, you might select the name UPDATE5.
```
  ++USERMOD(changename)   /* Replacement of existing module */
```
In place of fmid, use the actual FMID (function modification identifier). You can find this in the report generated by the SMP/E list command LIST SYSMODS. When you first install this exit, you probably will omit the PRE(xxxxxxx) SUP(yyyyyyy) because there probably is no prerequisite or superseding. If you later replace your own exit, you will code a different changename on the ++USERMOD statement and use the old changename with the SUP keyword.
```
  ++VER(Z038) FMID(fmid) PRE(xxxxxxx) SUP(yyyyyyy)
```
Replace exitname with the name of the exit. For some exits, the entry point name must match the exit name. The control section (CSECT) name should be the same name unless you choose a different name and code that name with the CSECT keyword. SYSLIB points to the target source library which contains the source code. You can omit the DISTLIB keyword and value unless stated otherwise in this information. It is only needed when SMP/E has copied the existing routine into the system while copying an entire library.
```
  ++SRC(exitname) SYSLIB(SUSERLIB) DISTLIB(ASRCLIB)
```
Place the source code after the ++SRC statement.
```
4.   (source code)
```
If you prefer, you can code the equivalent of a sequential concatenated DD statement as shown below:
```
    //         DD DSN=SYSPROG.EXITS.OBJ(modname),DISP=SHR
```