Name
APPENDDEF( )
Synopsis
The APPENDDEF( )
m4 directive allows you to append new
information to information that was previously defined. To
illustrate, consider that the locations of your
#include files are sometimes preset in the
appropriate devtools/OS directory. For
OS/UXPDS.V10, for example, the default is:
-I/usr/include -I/usr/ucbinclude
You can use this APPENDDEF( ) directive to add another directory to this list, without erasing what is already there:
APPENDDEF(`confINCDIRS', `-I/usr/local/include/db')
This causes the new directory to be appended to the declaration in the previous example:
-I/usr/include -I/usr/ucbinclude -I/usr/local/include/db
Even when you are not sure if a macro has been given a value by default, you can safely use this APPENDDEF( ) directive because no harm is caused by appending to an empty definition. See also PREPENDDEF( ).
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