man ocaml.m4 (1): Autoconf macros for OCaml

SUMMARY

 AC_PROG_OCAML
 AC_PROG_FINDLIB
 AC_PROG_OCAMLLEX
 AC_PROG_OCAMLYACC
 AC_PROG_CAMLP4
 AC_CHECK_OCAML_PKG([name])
 AC_CHECK_OCAML_MODULE(VARIABLE,NAME,MODULE,INCLUDE-PATHS)
 AC_CHECK_OCAML_WORD_SIZE

DESCRIPTION

ocaml.m4 is a file containing standard, useful autoconf macros for detecting the OCaml, findlib, OCaml packages, and so on in your autoconf-generated ./configure scripts.

To begin using these macros, you will need to copy the "ocaml.m4" file (usually located at "/usr/share/aclocal/ocaml.m4") to the autoconf macros directory in your project. Normally this is the "m4/" directory in your project, but the directory can be changed using the "AC_CONFIG_MACRO_DIR(DIR)" directive. If you have just created the "m4/" directory, then you may also need to do:

 aclocal -I m4

You can then add any of the macros described below to your "configure.ac" (or "configure.in"). Almost every OCaml project should use "AC_PROG_OCAML" first and probably "AC_PROG_FINDLIB" right after it.

This manual page does not describe how to use autoconf. For that you should read the detailed autoconf info file ("info autoconf").

AC_PROG_OCAML

This macro detects which tools of the usual OCaml toolchain are available. It defines and substitutes the following variables:

 OCAMLC          set to the name of the bytecode compiler
                   (eg. "ocamlc" or "ocamlc.opt"), or "no" if
                   no OCaml installation was found
 OCAMLOPT        the name of the native-code compiler, eg. "ocamlopt",
                   "ocamlopt.opt" or "no"
 OCAMLBEST       "byte" (if only the bytecode compiler is available)
                   or "opt" (if both bytecode and native code compilers
                   are available)
 OCAMLDEP        the name of the dependency resolver, eg. "ocamldep"
 OCAMLMKTOP      the name of ocamlmktop
 OCAMLMKLIB      the name of ocamlmklib
 OCAMLDOC        the name of ocamldoc
 OCAMLBUILD      the name of ocamlbuild
 OCAMLLIB        the OCaml library path (eg. C</usr/lib/ocaml/>)
 OCAMLVERSION    the compiler version (eg. C<3.11.0>)

Detecting if OCaml is installed

Unlike old versions of these macros, "AC_PROG_OCAML" does not exit if no OCaml installation is detected. Therefore if you want to detect if OCaml is installed you have to do something like this:

 AC_PROG_OCAML
 if test "$OCAMLC" = "no"; then
   AC_MSG_ERROR([You must install the OCaml compiler])
 fi

This behaviour and usage pattern are consistent with other macros of the "AC_PROG_*") family.

Cross-compiling

If the configure script is invoked for cross-compiling then "AC_PROG_OCAML" will detect the cross-compiler versions of the OCaml compiler, eg. "OCAMLC=i686-pc-mingw32-ocamlc" etc. This happens automatically, and for most purposes you don't need to worry about it.

AC_PROG_FINDLIB

This macro checks for the presence of the ocamlfind program (part of findlib). It defines and substitutes "OCAMLFIND" to the name of the ocamlfind program, or "no" if not found.

Note that this macro does not fail if ocamlfind is not found. If you want to force the user to install findlib, you should do:

 AC_PROG_FINDLIB
 if test "$OCAMLFIND" = "no"; then
   AC_MSG_ERROR([You must install OCaml findlib (the ocamlfind command)])
 fi

AC_PROG_OCAMLLEX

This checks for the ocamllex program and sets "OCAMLLEX" to the name of the program (eg. "ocamllex" or "ocamllex.opt"), or "no" if not found.

AC_PROG_OCAMLYACC

This checks for the ocamlyacc program and sets "OCAMLYACC" to the name of the program, or "no" if not found.

AC_PROG_CAMLP4

This checks for camlp4, and checks that the version matches the compiler version found previously. It sets "CAMLP4" to the name of the basic camlp4 program, or "no" if not found.

The macro also checks for other tools of the camlp4 suite like camlp4o, camlp4orf, etc. For each of them, a fully capitalized variable is set to the tool name (or "no" if not found); all variable are substituted for when filling .in files. The full list of tools and respective variable names is as follows:

 camlp4        CAMLP4
 camlp4boot    CAMLP4BOOT
 camlp4o       CAMLP4O
 camlp4of      CAMLP4OF
 camlp4oof     CAMLP4OOF
 camlp4orf     CAMLP4ORF
 camlp4prof    CAMLP4PROF
 camlp4r       CAMLP4R
 camlp4rf      CAMLP4RF

AC_CHECK_OCAML_PKG

This is the main macro that can be used to detect the presence of OCaml findlib packages. This macro uses ocamlfind to look up findlib packages (and thus requires that findlib itself has been installed, and that the package has been properly packaged with a META file etc.) If you want to find an OCaml findlib package which hasn't been installed with findlib then you should try using "AC_CHECK_OCAML_MODULE" instead.

 AC_CHECK_OCAML_PKG([name])

checks for an OCaml findlib package with the given name. If found, it defines and substitutes the variable "OCAML_PKG_name" where the "name" part is substituted for the package name by replacing all dashes with underscores.

For example,

 AC_CHECK_OCAML_PKG([xml-light])

will set "OCAML_PKG_xml_light" to either "xml-light" or "no".

To have the configure script fail if a package is not installed, do:

 AC_CHECK_OCAML_PKG([foo])
 if test "$OCAML_PKG_foo" = "no"; then
   AC_MSG_ERROR([Please install OCaml findlib module 'foo'.])
 fi

In your Makefile.in, use the substitution variable in conjunction with ocamlfind, eg:

 .ml.cmo:
   $(OCAMLFIND) ocamlc -package @OCAML_PKG_foo@ -c $< -o $@

Note that also in the substitution variable dashes are replaced with underscores.

Checking for alternative findlib package names

In the (unlikely) case where the same library corresponds to different findlib package names on different systems, you can improve portability by checking for the alternative names passing a second argument to "AC_CHECK_OCAML_PKG":

 AC_CHECK_OCAML_PKG(PKGNAME,ALTERNATIVE-NAMES)

The behaviour is the same as before if "PKGNAME" is found. Otherwise all names in "ALTERNATIVE-NAMES" are tested in turn as findlib package names. If one is found, it is set as the value set by the macro and substituted in .in files; otherwise "no" is set.

Note that the variable name is determined by "PKGNAME", while the value depends on the actual alternative name found.

For example, to detect the camlzip findlib package, either called "zip" or "camlzip", and to store the found value in the "OCAML_PKG_zip" variable you can do in your configure.ac:

 AC_CHECK_OCAML_PKG(zip,camlzip)

and have a portable Makefile.in build line such as:

 .ml.cmo:
   $(OCAMLFIND) ocamlc -package @OCAML_PKG_zip@ -c $< -o $@

AC_CHECK_OCAML_MODULE(VARIABLE,NAME,MODULE,INCLUDE-PATHS)

"AC_CHECK_OCAML_MODULE" is the hairier alternative to "AC_CHECK_OCAML_PKG". You should always use "AC_CHECK_OCAML_PKG" and ocamlfind/findlib if possible.

The parameters are:

VARIABLE: This is the environment variable that is set. It will either be set to the include path, or to "no" if the module was not found.
NAME: This is the name of the module we are looking for. This parameter is just used for printing messages, and does not affect how the module is found.
MODULE: This should be an OCaml module name, representing the module name being looked up. You can put sub-modules here, eg. "CalendarLib.Date"
INCLUDE-PATHS: This is the default list of include directories to search, eg. "+calendar"

For example, the following code will check for the OCaml Calendar module, and will distinguish between version 1 and version 2 of this module (which have incompatible APIs).

 AC_CHECK_OCAML_PKG(calendar)
 AC_CHECK_OCAML_MODULE(is_calendar2,calendar,[CalendarLib.Date],[+calendar])

After the above code has run, variables "OCAML_PKG_calendar" and "is_calendar2" will be set as follows:

 OCAML_PKG_calendar  is_calendar2  Result
 
 yes                 +calendar     Calendar v2 is installed
 yes                 no            Calendar v1 is installed
 no                  no            No Calendar module installed

AC_CHECK_OCAML_WORD_SIZE

This checks the word size of the OCaml compiler, and sets "OCAML_WORD_SIZE" to either 32 or 64.

FILES

/usr/share/aclocal/ocaml.m4

AUTHORS

Various people have contributed to these macros over many years:

Olivier Andrieu
Jean-Christophe Filliatre
Richard W.M. Jones
Georges Mariano
Jim Meyering
Stefano Zacchiroli

LICENSE

 Copyright X 2009      Richard W.M. Jones
 Copyright X 2009      Stefano Zacchiroli
 Copyright X 2000-2005 Olivier Andrieu
 Copyright X 2000-2005 Jean-Christophe Filliatre
 Copyright X 2000-2005 Georges Mariano
 
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modification,
 are permitted provided that the following conditions are met:
 
 * Redistributions of source code must retain the above copyright notice, this
 list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice,
 this list of conditions and the following disclaimer in the documentation
 and/or other materials provided with the distribution.
 * The names of the contributors may not be used to endorse or promote
 products derived from this software without specific prior written
 permission.
 
 THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

REPORTING BUGS

Please report bugs to the authors at the project page: <http://forge.ocamlcore.org/projects/ocaml-autoconf/>, using the forge bug tracker <http://forge.ocamlcore.org/tracker/?group_id=69>.