The Swap Library List Entry command is designed for the situation
where you want to add a library to the user portion of the library
list, but the user may already have a list that is at the maximum
number (25 libraries).
SWPLIBLE is designed to swap out the last library on the list and
insert your library. When you have completed your function, you swap
back.
For example, assume you need to add the library NEWLIB to the library
list and do not know if the list is at the maximum. The following
code operates correctly whether the user is at the maximum or not:
DCL &RTNLIB *CHAR LEN(10)
.
SWPLIBLE ADDLIB(NEWLIB) RMVLIB(*LAST) RTNLIB(&RTNLIB)
.
. /* Your function using the added lib */
.
SWPLIBLE ADDLIB(&RTNLIB) RMVLIB(NEWLIB) +
If the library list is not at the maximum, no library is removed from
the library list, NEWLIB is added to the list and the special value
*NONE is returned in the return variable &RTNLIB. If the library
list is at the maximum, RTNLIB contains the name of the library that
was removed from the list - RMVLIB(*LAST) requests the last library
on the list.
When it is time to reset the library list, the second SWPLIBLE
command adds the RTNLIB library from the first SWPLIBLE and removes
the specified library. If the first SWPLIBLE command had returned
*NONE for RTNLIB, no library is added.
The SWPLIBLE command uses the system commands ADDLIBLE and RMVLIBLE.
If you attempt to add a library that already exists on the library
list, the system sends CPF2103 as an escape message. If you attempt
to remove a library that does not exist on the library list, the
system sends CPF2104 as an escape message. These messages will be
resent to your program.
Command parameters *CMD
------------------
ADDLIB The library to be added to the library list. The
special value *NONE exists to cause no library to be
added.
ADDPOS The position in the library list to add the library.
*FIRST and *LAST are the only values that may be
entered and have the same meaning as on ADDLIBLE.
*LAST is the default. The reference library
function supported on ADDLIBLE is not supported on
SWPLIBLE.
RMVLIB The library to be removed from the library list. A
specific library or the special value *LAST may be
specified. *LAST is the default.
If *LAST is specified and the library list is not at
its maximum, no library is removed and the RTNLIB
value will be *NONE. If the library list is at its
maximum, the last library in the list is removed.
RTNLIB A return variable that is optional. If used, it
must be declared as *CHAR LEN(10). The intent of
this parameter is for it to be used when
RMVLIB(*LAST) is used. The value returned will be
*NONE (if no library was removed) or the name of the
library removed.
Restrictions
------------
Because the command returns a variable, SWPLIBLE can only be used in
a CL program.
Prerequisites
-------------
The following TAA Tools must be on your system:
SNDCOMPMSG Send completion message
Implementation
--------------
None, the tool is ready to use.
Objects used by the tool
------------------------
Object Type Attribute Src member Src file
------ ---- --------- ---------- ----------
SWPLIBLE *CMD TAALIBM QATTCMD
TAALIBMC *PGM CLP TAALIBMC QATTCL
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