Re: How to test if a autoconf macro exists?

[Eric Blake]

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According to Bernd Jendrissek on 2/4/2008 4:51 AM:
|> I am using the macro  AM_PATH_XML2(2.5.0) in my configure.ac which works

Please get in the habit of using proper quoting.  That should be:

AM_PATH_XML2([2.5.0])


|>
|> I think I can try the following workarounds:
|> a) Copy the contents of AM_PATH_XML2 to my acinclude.m4 and redistribute it
|
| aclocal does that for the users of your tarball.  That's why you as
| the package maintainer need to have AM_PATH_XML2 installed where
| aclocal can find it.  As long as you don't ask your users to run
| aclocal, they won't have to have the macro installed as the
| distributed aclocal.m4 will already contain it.

This point is valid.

|>
|> if EXISTS_MACRO( [AM_PATH_XML2] ) ; then
|>
|> Does anything like this exists yet?

Fix your quoting again - the trailing space in your usage would be
interpreted literally, and I doubt you will find the macro
'AM_PATH_XML2 ' defined on any machine.  But yes:

m4_ifdef([AM_PATH_XML2], [code if defined], [code if undefined])

is valid in autoconf.  I would recommend the m4sugar spelling (m4_ifdef)
rather than the raw M4 spelling (ifdef), since future releases of autoconf
might disable raw spellings to be namespace clean.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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