* Compilers and Preprocessors:: Checking for compiling programs
* System Services:: Operating system services
* Posix Variants:: Special kludges for specific Posix variants
+* Erlang Libraries:: Checking for the existence of Erlang libraries
Common Behavior
* Generic Compiler Characteristics:: Language independent tests and features
* C Compiler:: Checking its characteristics
* C++ Compiler:: Likewise
+* Erlang Compiler and Interpreter:: Likewise
* Fortran Compiler:: Likewise
Writing Tests
want to use it.
@end defvar
+@defvar ERLCFLAGS
+@ovindex ERLCFLAGS
+Debugging and optimization options for the Erlang compiler. If it is not set
+in the environment when @command{configure} runs, the default value is empty.
+@command{configure} uses this variable when compiling programs to test for
+Erlang features.
+@end defvar
+
@defvar FCFLAGS
@ovindex FCFLAGS
Debugging and optimization options for the Fortran compiler. If it
otherwise the package won't support separated builds.
@end table
+For the more specific installation of Erlang libraries, the following variables
+are defined:
+
+@defvar ERLANG_INSTALL_LIB_DIR
+@ovindex ERLANG_INSTALL_LIB_DIR
+The common parent directory of Erlang library installation directories.
+This variable is set by calling the @code{AC_ERLANG_SUBST_INSTALL_LIB_DIR}
+macro in @file{configure.ac}.
+@end defvar
+
+@defvar ERLANG_INSTALL_LIB_DIR_@var{library}
+@ovindex ERLANG_INSTALL_LIB_DIR_@var{library}
+The installation directory for Erlang library @var{library}.
+This variable is set by calling the
+@samp{AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR(@var{library}, @var{version}}
+macro in @file{configure.ac}.
+@end defvar
+
+@xref{Erlang Libraries}, for details.
+
@node Build Directories
@subsection Build Directories
* Compilers and Preprocessors:: Checking for compiling programs
* System Services:: Operating system services
* Posix Variants:: Special kludges for specific Posix variants
+* Erlang Libraries:: Checking for the existence of Erlang libraries
@end menu
@node Common Behavior
* Generic Compiler Characteristics:: Language independent tests and features
* C Compiler:: Checking its characteristics
* C++ Compiler:: Likewise
+* Erlang Compiler and Interpreter:: Likewise
* Fortran Compiler:: Likewise
@end menu
@end defmac
+@node Erlang Compiler and Interpreter
+@subsection Erlang Compiler and Interpreter Characteristics
+@cindex Erlang
+
+Autoconf defines the following macros for determining paths to the essential
+Erlang/OTP programs:
+
+@defmac AC_ERLANG_PATH_ERLC (@ovar{value-if-not-found}, @ovar{path})
+@acindex{ERLANG_PATH_ERLC}
+@ovindex ERLC
+@ovindex ERLCFLAGS
+Determine an Erlang compiler to use. If @code{ERLC} is not already set in the
+environment, check for @command{erlc}. Set output variable @code{ERLC} to the
+complete path of the compiler command found.
+
+The optional two arguments have the same meaning as the two last arguments of
+macro @code{AC_PROG_PATH} for looking for the @command{erlc} program. For
+example, to look for @command{erlc} only in the @file{/usr/lib/erlang/bin}
+directory:
+
+@example
+AC_ERLANG_PATH_ERLC([not found], [/usr/lib/erlang/bin])
+@end example
+@end defmac
+
+@defmac AC_ERLANG_NEED_ERLC (@ovar{path})
+@acindex{ERLANG_NEED_ERLC}
+@ovindex AC_ERLANG_PATH_ERLC
+@ovindex ERLC
+@ovindex ERLCFLAGS
+A simplified variant of the @code{AC_ERLANG_PATH_ERLC} macro, that prints an
+error message and exits the @command{configure} script if the @command{erlc}
+program is not found.
+@end defmac
+
+@defmac AC_ERLANG_PATH_ERL (@ovar{value-if-not-found}, @ovar{path})
+@acindex{ERLANG_PATH_ERL}
+@ovindex ERL
+Determine an Erlang interpreter to use. If @code{ERL} is not already set in the
+environment, check for @command{erl}. Set output variable @code{ERL} to the
+complete path of the interpreter command found.
+
+The optional two arguments have the same meaning as the two last arguments of
+macro @code{AC_PROG_PATH} for looking for the @command{erl} program. For
+example, to look for @command{erl} only in the @file{/usr/lib/erlang/bin}
+directory:
+
+@example
+AC_ERLANG_PATH_ERL([not found], [/usr/lib/erlang/bin])
+@end example
+@end defmac
+
+@defmac AC_ERLANG_NEED_ERL (@ovar{path})
+@acindex{ERLANG_NEED_ERL}
+@ovindex AC_ERLANG_PATH_ERL
+@ovindex ERL
+A simplified variant of the @code{AC_ERLANG_PATH_ERL} macro, that prints an
+error message and exits the @command{configure} script if the @command{erl}
+program is not found.
+@end defmac
+
@node Fortran Compiler
@subsection Fortran Compiler Characteristics
@end defmac
+@node Erlang Libraries
+@section Erlang Libraries
+@cindex Erlang, Library, checking
+
+The following macros check for an installation of Erlang/OTP, and for the
+presence of certain Erlang libraries. All those macros require the
+configuration of an Erlang interpreter and an Erlang compiler
+(@pxref{Erlang Compiler and Interpreter}).
+
+@defmac AC_ERLANG_SUBST_ROOT_DIR
+@acindex{ERLANG_SUBST_ROOT_DIR}
+@ovindex ERLANG_ROOT_DIR
+
+Set the output variable @code{ERLANG_ROOT_DIR} to the path of the root
+directory of Erlang/OTP (as returned by Erlang's @code{code:root_dir/0}
+function), which is the directory where it is installed. The result of this
+test is cached if caching is enabled when running @code{configure}.
+@end defmac
+
+@defmac AC_ERLANG_SUBST_LIB_DIR
+@acindex{ERLANG_SUBST_LIB_DIR}
+@ovindex ERLANG_LIB_DIR
+
+Set the output variable @code{ERLANG_LIB_DIR} to the path of the library
+directory of Erlang/OTP (as returned by Erlang's
+@code{code:lib_dir/0} function), which subdirectories each contain an installed
+Erlang/OTP library. The result of this test is cached if caching is enabled
+when running @code{configure}.
+@end defmac
+
+@defmac AC_ERLANG_CHECK_LIB (@var{library}, @ovar{action-if-found}, @ovar{action-if-not-found})
+@acindex{ERLANG_CHECK_LIB}
+@ovindex ERLANG_LIB_DIR_library
+
+Test whether the Erlang/OTP library @var{library} is installed by calling
+Erlang's @code{code:lib_dir/1} function. The result of this test is cached if
+caching is enabled when running @code{configure}. @var{action-if-found} is a
+list of shell commands to run if the library is installed;
+@var{action-if-not-found} is a list of shell commands to run if it is not.
+Additionally, if the library is installed, the output variable
+@samp{ERLANG_LIB_DIR_@var{library}} is set to the path to the library
+installation directory. For example, to check if the @code{stdlib} library is
+installed:
+
+@example
+AC_ERLANG_CHECK_LIB([stdlib],
+ [echo "stdlib is installed in $ERLANG_LIB_DIR_stdlib"],
+ [AC_MSG_ERROR([stdlib was not found!])])
+@end example
+@end defmac
+
+In addition to the above macros, which test installed Erlang libraries, the
+following macros determine paths to built libraries installation directories:
+
+@defmac AC_ERLANG_SUBST_INSTALL_LIB_DIR
+@acindex{ERLANG_SUBST_INSTALL_LIB_DIR}
+@ovindex ERLANG_INSTALL_LIB_DIR
+
+Set the @code{ERLANG_INSTALL_LIB_DIR} output variable to the directory into
+which every built Erlang library should be installed in a separate subdirectory.
+If this variable is not set in the environment when @command{configure} runs,
+its default value is @code{$ERLANG_LIB_DIR}, as determined by the
+@code{AC_ERLANG_SUBST_LIB_DIR} macro.
+@end defmac
+
+@defmac AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR (@var{library}, @var{version})
+@acindex{ERLANG_SUBST_INSTALL_LIB_SUBDIR}
+@ovindex ERLANG_INSTALL_LIB_DIR_@var{library}
+
+Set the @samp{ERLANG_INSTALL_LIB_DIR_@var{library}} output variable to the
+directory into which the built Erlang library @var{library} version
+@var{version} should be installed. If this variable is not set in the
+environment when @command{configure} runs, its default value is
+@samp{$ERLANG_INSTALL_LIB_DIR/@var{library}-@var{version}}, the
+@code{ERLANG_INSTALL_LIB_DIR} variable being set by the
+@code{AC_ERLANG_SUBST_INSTALL_LIB_DIR} macro.
+@end defmac
+
+
+
@c ========================================================= Writing Tests
Do compilation tests using @code{FC} and use extension @file{.f} (or
whatever has been set by @code{AC_FC_SRCEXT}) for test programs. Use
compilation flags: @code{FCFLAGS}.
+
+@item Erlang
+Compile and execute tests using @code{ERLC} and @code{ERL} and use extension
+@file{.erl} for test Erlang modules. Use compilation flags: @code{ERLCFLAGS}.
@end table
@end defmac
AC_INIT([Hello], [1.0], [bug-hello@@example.org])
AC_DEFINE([HELLO_WORLD], ["Hello, World\n"],
[Greetings string.])
+AC_LANG(C)
AC_LANG_CONFTEST(
[AC_LANG_SOURCE([[const char hw[] = "Hello, World\n";]])])
gcc -E -dD -o - conftest.c
const char hw[] = "Hello, World\n";
@end example
+When the test language is Fortran or Erlang, the @code{AC_DEFINE} definitions
+are not automatically translated as constants in the source code by this macro.
+
@defmac AC_LANG_PROGRAM (@var{prologue}, @var{body})
@acindex{LANG_PROGRAM}
Expands into a source file which consists of the @var{prologue}, and
@}
@end example
+In Erlang tests, the created @file{conftest.erl} source file is that of an
+Erlang module called @code{conftest}. This module defines and exports one
+@code{start/0} function, which is called to perform the test. The
+@var{prologue} is optional code that is inserted between the module header
+and the @code{start/0} function definition. @var{body} is the body of the
+@code{start/0} function (without the final period).
+
+For instance:
+
+@example
+AC_INIT([Hello], [1.0], [bug-hello@@example.org])
+AC_LANG(Erlang)
+AC_LANG_CONFTEST(
+[AC_LANG_PROGRAM([[-define(HELLO_WORLD, "Hello, world!").]],
+ [[io:format("~s~n", [?HELLO_WORLD])]])])
+cat conftest.erl
+@end example
+
+@noindent
+results in:
+
+@example
+-module(conftest).
+-export([start/0]).
+-define(HELLO_WORLD, "Hello, world!").
+start() ->
+io:format("~s~n", [?HELLO_WORLD])
+.
+@end example
@defmac AC_LANG_CALL (@var{prologue}, @var{function})
@acindex{LANG_CALL}
This function will probably be replaced in the future by a version
which would enable specifying the arguments. The use of this macro is
not encouraged, as it violates strongly the typing system.
-@end defmac
+This macro cannot be used for Erlang tests.
+@end defmac
@defmac AC_LANG_FUNC_LINK_TRY (@var{function})
@acindex{LANG_FUNC_LINK_TRY}
It is considered to be severely broken, and in the future will be
removed in favor of actual function calls (with properly typed
arguments).
+
+This macro cannot be used for Erlang tests.
@end defmac
@node Running the Preprocessor
Nevertheless, if you need to run the preprocessor, then use
@code{AC_PREPROC_IFELSE}.
+Note that the Erlang and Fortan languages have no preprocessor, hence the
+macros described in this section cannot be used for tests in those languages.
+
@defmac AC_PREPROC_IFELSE (@var{input}, @ovar{action-if-true}, @ovar{action-if-false})
@acindex{PREPROC_IFELSE}
Run the preprocessor of the current language (@pxref{Language Choice})
Linker}).
@end defmac
+When setting Erlang as the test language, the @var{input} must be the source
+code of a module named @code{conftest}. @code{AC_COMPILE_IFELSE} generates a
+@file{conftest.beam} file that can be interpreted by the Erlang virtual
+machine. Using @code{AC_LANG_PROGRAM} to specify the test program ensures that
+the Erlang module has the right name.
+
@node Running the Linker
@section Running the Linker
use @code{AC_RUN_IFELSE} if you need to do that (@pxref{Run Time}).
@end defmac
+Erlang being an interpreted language, Erlang programs do not need linking,
+hence @code{AC_LINK_IFELSE} cannot be used with Erlang tests.
@node Run Time
@samp{yes}, and then use an alternate method to get the results instead
of calling the macros.
+Erlang tests must exit themselves the Erlang VM by calling the @code{halt/1}
+function: the given status code is used to determine the success of the test
+(status is @code{0}) or its failure (status is different than @code{0}), as
+explained above. If a test must output configuration information, since
+halting the VM may truncate data output into the standard output, it is
+recommended to output data into the @file{conftest.out} file, using the
+function of module @code{file}. That file is automatically deleted by
+@code{AC_RUN_IFELSE}.
+
+For instance, a simplified implementation of Autoconf's
+@code{AC_ERLANG_SUBST_LIB_DIR} macro is:
+
+@example
+AC_INIT([LibdirTest], [1.0], [bug-libdirtest@@example.org])
+AC_ERLANG_NEED_ERL
+AC_LANG(Erlang)
+AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM([], [dnl
+ file:write_file("conftest.out", code:lib_dir()),
+ halt(0)])],
+ [echo "code:lib_dir() returned: `cat conftest.out`"],
+ [AC_MSG_FAILURE([test Erlang program execution failed])])
+@end example
+
@node Systemology
@section Systemology
projects / thirdparty / autoconf.git / commitdiff
