20.5 How Do I #define Installation Directories?
| | My program needs library files, installed in datadir and
similar. If I use
| | AC_DEFINE_UNQUOTED([DATADIR], [$datadir],
[Define to the read-only architecture-independent
data directory.])
|
I get
| | #define DATADIR "${prefix}/share"
|
|
As already explained, this behavior is on purpose, mandated by the
GNU Coding Standards, see Installation Directory Variables. There are several means to achieve a similar goal:
- -
Do not use
AC_DEFINE but use your makefile to pass the
actual value of datadir via compilation flags.
See section Installation Directory Variables, for the details.
- -
This solution can be simplified when compiling a program: you may either
extend the
CPPFLAGS:
| | CPPFLAGS = -DDATADIR='"$(datadir)"' @CPPFLAGS@
|
If you are using Automake, you should use AM_CPPFLAGS instead:
| | AM_CPPFLAGS = -DDATADIR='"$(datadir)"'
|
Alternatively, create a dedicated header file:
| | DISTCLEANFILES = myprog-paths.h
myprog-paths.h: Makefile
echo '#define DATADIR "$(datadir)"' >$@
|
- -
Use
AC_DEFINE but have configure compute the literal
value of datadir and others. Many people have wrapped macros to
automate this task; for an example, see the macro AC_DEFINE_DIR from
the Autoconf Macro Archive.
This solution does not conform to the GNU Coding Standards.
- -
Note that all the previous solutions hard wire the absolute name of
these directories in the executables, which is not a good property. You
may try to compute the names relative to
prefix, and try to
find prefix at runtime, this way your package is relocatable.