Re: Configure help

[Ralf Wildenhues]

Hi Bob,

* Bob Rossi wrote on Tue, Jul 05, 2005 at 05:25:21PM CEST:
> 
> I am having a little trouble using autoconf to configure my package.
> Currently, I am tring to build a package that depends on another
> package. Basically CGDB (main package) depends on Readline (second
> package).
> 
> I am using   
>    AC_CONFIG_SUBDIRS(readline-5.0)
> to configure readline. This works well.
> 
> There is 2 problems I need to solve. The first is, since readline is
> installed in cgdb/readline-5.0, I need a way of telling 
> 
>      AC_CHECK_HEADERS(readline.h history.h)
>      AC_CHECK_LIB(readline, readline,
>        [AC_DEFINE(HAVE_LIBREADLINE, 1, readline library)],
>          AC_MSG_ERROR([Packaged readline failed to build.
>          Please submit a bug report.]))
> 
> the above 2 commands how to find the installed readline. For instance,
> AC_CHECK_LIB does not know to look in cgdb/readline-5.0 for readline.h.
> What is the best way to accomplish this? 

Well, I would give the user the choice to
- either use your shipped readline library 
- or use a previously installed readline library 
- or (if appropriate) disable readline functionality.

Something like a
  --with-readline[=included]
might be useful, although I don't know of an established convention for
the optional `=included' part.

> Also, AC_CHECK_LIB can not even look for libreadline.a until after the
> "make" is done. Is there a way to ./configure && make && make install
> the readline package, and then continue with CGDB's configure?

Well, if you use your prepackaged readline, there is no need to check
for either the headers nor the library -- you know they _will_ be there.
(Of course, in that case your configure.ac should set appropriate flags
for preprocessor and linker/libs.)  So, the AC_CHECK_HEADERS/
AC_CHECK_LIB tests should not be invoked then.  Use ordering in toplevel
Makefile.am variable SUBDIRS to ensure readline gets built before its
users.

Regards,
Ralf