about documentation of AC_CHECK_HEADERS

[Vincent Torri]

Hey,

in the manual, one can read in 
http://www.gnu.org/software/autoconf/manual/autoconf.html#Generic-Headers

"For each given system header file header-file in the blank-separated 
argument list that exists, define HAVE_header-file (in all capitals). If 
action-if-found is given, it is additional shell code to execute when one 
of the header files is found. You can give it a value of `break' to break 
out of the loop on the first match. If action-if-not-found is given, it is 
executed when one of the header files is not found."

if I do that:

AC_CHECK_HEADERS([foo.h bar.h], [have_headers="yes"], [have_headers="no"])

So, 'action-if-found' and 'action-if-not-found' are given.

Now, suppose that foo.h exists, but bar.h does not.

According to the first part of the doc : "If action-if-found is given, it 
is additional shell code to execute when one of the header files is 
found.", as foo.h exists, have_headers="yes" is executed.

But according to the second part: "If action-if-not-found is given, it is
executed when one of the header files is not found", as bar.h does not 
exist, have_headers="no" is executed...

I don't know the real behavior of AC_CHECK_HEADERS, but clearly, there is 
a problem with the documentation.

Imho, the correct behavior woul be "if action-if-found is given, it is 
additional shell code to execute when all the header files are found. If 
action-if-not-found is given, it is executed when one of the header files 
is not found"

am I wrong ?

Vincent Torri