Autoconf requires @acronym{GNU} M4 in order to generate the scripts. It uses
features that some versions of M4, including @acronym{GNU} M4 1.3,
-do not have. You must use version 1.4 or later of @acronym{GNU} M4.
+do not have. You should use version 1.4.3 or later of @acronym{GNU} M4.
@xref{Autoconf 1}, for information about upgrading from version 1.
@xref{History}, for the story of Autoconf's development. @xref{FAQ},
lists, pointers to a list of known bugs, etc.
Mail suggestions to @email{autoconf@@gnu.org, the Autoconf mailing
-list}.
+list}. Past suggestions are
+@uref{http://lists.gnu.org/archive/html/autoconf/, archived}.
-Bug reports should be emailed to @email{bug-autoconf@@gnu.org, the
-Autoconf Bugs mailing list}. If possible, first check that your bug is
+Mail bug reports to @email{bug-autoconf@@gnu.org, the
+Autoconf Bugs mailing list}. Past bug reports are
+@uref{http://lists.gnu.org/archive/html/bug-autoconf/, archived}.
+
+If possible, first check that your bug is
not already solved in current development versions, and that it has not
been reported yet. Be sure to include all the needed information and a
short @file{configure.ac} that demonstrates the problem.
-Autoconf's development tree is accessible via @acronym{CVS}; see the
+Autoconf's development tree is accessible via anonymous @acronym{CVS}; see the
@uref{http://savannah.gnu.org/projects/autoconf/, Autoconf
Summary} for details. Patches relative to the
current @acronym{CVS} version can be sent for review to the
@email{autoconf-patches@@gnu.org, Autoconf Patches mailing list}.
+Past patches are
+@uref{http://lists.gnu.org/archive/html/autoconf-patches/, archived}.
-Archives of @email{bug-autoconf@@gnu.org} can be
-found in @uref{http://lists.gnu.org/archive/html/bug-autoconf/}, and
-similarly for the other mailing lists.
-
-Because of its mission, Autoconf includes only a set of often-used
+Because of its mission, the Autoconf package itself
+includes only a set of often-used
macros that have already demonstrated their usefulness. Nevertheless,
if you wish to share your macros, or find existing ones, see the
@uref{http://www.gnu.org/software/ac-archive/, @acronym{GNU} Autoconf Macro
three lines below are equivalent:
@example
-AC_CHECK_HEADERS(stdio.h, [], [], [])
-AC_CHECK_HEADERS(stdio.h,,,)
-AC_CHECK_HEADERS(stdio.h)
+AC_CHECK_HEADERS([stdio.h], [], [], [])
+AC_CHECK_HEADERS([stdio.h],,,)
+AC_CHECK_HEADERS([stdio.h])
@end example
It is best to put each macro call on its own line in
Warnings about @samp{syntax} are enabled by default, and the environment
variable @env{WARNINGS}, a comma separated list of categories, is
-honored. Passing @samp{-W @var{category}} will actually behave as if
+honored as well. Passing @samp{-W @var{category}} will actually behave as if
you had passed @samp{--warnings=syntax,$WARNINGS,@var{category}}. If
you want to disable the defaults and @env{WARNINGS}, but (for example)
enable the warnings about obsolete constructs, you would use @option{-W
Install the missing auxiliary files in the package. By default, files
are copied; this can be changed with @option{--symlink}.
-This option triggers calls to @samp{automake --add-missing},
+If deemed appropriate, this option triggers calls to
+@samp{automake --add-missing},
@samp{libtoolize}, @samp{autopoint}, etc.
@item --symlink
Warnings about @samp{syntax} are enabled by default, and the environment
variable @env{WARNINGS}, a comma separated list of categories, is
-honored. Passing @samp{-W @var{category}} will actually behave as if
+honored as well. Passing @samp{-W @var{category}} will actually behave as if
you had passed @samp{--warnings=syntax,$WARNINGS,@var{category}}. If
you want to disable the defaults and @env{WARNINGS}, but (for example)
enable the warnings about obsolete constructs, you would use @option{-W
error output and exit with failure (exit status is 63). For example:
@example
-AC_PREREQ(@value{VERSION})
+AC_PREREQ([@value{VERSION}])
@end example
This macro is the only macro that may be used before @code{AC_INIT}, but
@c The asis prevents RCS from changing the example in the manual.
@example
-AC_REVISION($@asis{Revision: 1.30 }$)
+AC_REVISION([$@asis{Revision: 1.30 }$])
@end example
@noindent
produces this in @command{configure}:
@example
-#! /bin/sh
+#!/bin/sh
# From configure.ac Revision: 1.30
@end example
@end defmac
@example
@dots{} && my_foos="$my_foos fooo"
@dots{} && my_foos="$my_foos foooo"
-AC_CONFIG_FOOS($my_foos)
+AC_CONFIG_FOOS([$my_foos])
@end example
@noindent
and use this instead:
@example
-@dots{} && AC_CONFIG_FOOS(fooo)
-@dots{} && AC_CONFIG_FOOS(foooo)
+@dots{} && AC_CONFIG_FOOS([fooo])
+@dots{} && AC_CONFIG_FOOS([foooo])
@end example
The macros @code{AC_CONFIG_FILES} and @code{AC_CONFIG_HEADERS} use
@samp{@var{output}:@var{inputs}}. The file @var{output} is instantiated
from its templates, @var{inputs} (defaulting to @samp{@var{output}.in}).
-For instance
-@samp{AC_CONFIG_FILES(Makefile:boiler/top.mk:boiler/bot.mk)} asks for
+@samp{AC_CONFIG_FILES([Makefile:boiler/top.mk:boiler/bot.mk)]},
+for example, asks for
the creation of @file{Makefile} that will be the expansion of the
output variables in the concatenation of @file{boiler/top.mk} and
@file{boiler/bot.mk}.
example, an input shell script should begin like this:
@example
-#! /bin/sh
+#!/bin/sh
# @@configure_input@@
@end example
A corollary is that you should not use these variables except in
Makefiles. For instance, instead of trying to evaluate @code{datadir}
in @file{configure} and hard-coding it in Makefiles using
-e.g., @samp{AC_DEFINE_UNQUOTED(DATADIR, "$datadir", [Data directory.])},
+e.g., @samp{AC_DEFINE_UNQUOTED([DATADIR], ["$datadir"], [Data directory.])},
you should add
@samp{-DDATADIR="$(datadir)"} to your @code{CPPFLAGS}.
(Be careful if you copy these lines directly into your Makefile, as you
will need to convert the indented lines to start with the tab character.)
-In addition, you should use @samp{AC_CONFIG_FILES([stamp-h], [echo
-timestamp > stamp-h])} so @file{config.status} will ensure that
-@file{config.h} is considered up to date. @xref{Output}, for more
-information about @code{AC_OUTPUT}.
+In addition, you should use
+
+@example
+AC_CONFIG_FILES([stamp-h], [echo timestamp > stamp-h])
+@end example
+
+@noindent
+so @file{config.status} will ensure that @file{config.h} is considered up to
+date. @xref{Output}, for more information about @code{AC_OUTPUT}.
@xref{config.status Invocation}, for more examples of handling
configuration-related dependencies.
For example, this call:
@example
-AC_CONFIG_LINKS(host.h:config/$machine.h
- object.h:config/$obj_format.h)
+AC_CONFIG_LINKS([host.h:config/$machine.h
+ object.h:config/$obj_format.h])
@end example
@noindent
if test "$package_foo_enabled" = yes; then
$my_subdirs="$my_subdirs foo"
fi
-AC_CONFIG_SUBDIRS($my_subdirs)
+AC_CONFIG_SUBDIRS([$my_subdirs])
@end example
@noindent
@example
if test "$package_foo_enabled" = yes; then
- AC_CONFIG_SUBDIRS(foo)
+ AC_CONFIG_SUBDIRS([foo])
fi
@end example
@example
if test -d $srcdir/foo; then
- AC_CONFIG_SUBDIRS(foo)
+ AC_CONFIG_SUBDIRS([foo])
fi
@end example
For instance,
@example
-AC_CHECK_TYPES(struct $Expensive*)
+AC_CHECK_TYPES([struct $Expensive*])
@end example
@noindent
AC_PROG_LEX
if test "$LEX" != flex; then
LEX="$SHELL $missing_dir/missing flex"
- AC_SUBST(LEX_OUTPUT_ROOT, lex.yy)
- AC_SUBST(LEXLIB, '')
+ AC_SUBST([LEX_OUTPUT_ROOT], [lex.yy])
+ AC_SUBST([LEXLIB], [''])
fi
@end example
For example, if the user runs @samp{configure --host=i386-gnu}, then
this call:
@example
-AC_CHECK_TOOL(RANLIB, ranlib, :)
+AC_CHECK_TOOL([RANLIB], [ranlib], [:])
@end example
@noindent
sets @code{RANLIB} to @file{i386-gnu-ranlib} if that program exists in
appear the standard C library on some hosts, and in special libraries
like @code{nsl} on other hosts. On some hosts the special libraries
contain variant implementations that you may not want to use. These
-days it is normally better to use @code{AC_SEARCH_LIBS(gethostbyname,
-nsl)} instead of @code{AC_CHECK_LIB(nsl, gethostbyname)}.
+days it is normally better to use @code{AC_SEARCH_LIBS([gethostbyname],
+[nsl])} instead of @code{AC_CHECK_LIB([nsl], [gethostbyname])}.
@end defmac
To work around this porting mess, you can use code like the following.
-@example
+@smallexample
#include <math.h>
#ifndef isnan
static inline int isinf_d (double x) @{ return isnan (x - x); @}
static inline int isinf_ld (long double x) @{ return isnan (x - x); @}
#endif
-@end example
+@end smallexample
Use @code{AC_C_INLINE} (@pxref{C Compiler}) so that this code works on
compilers that lack the @code{inline} keyword. Some optimizing
If the system has the @code{getloadavg} function, define
@code{HAVE_GETLOADAVG}, and set @code{GETLOADAVG_LIBS} to any libraries
-needed to get that function. Also add @code{GETLOADAVG_LIBS} to
+necessary to get that function. Also add @code{GETLOADAVG_LIBS} to
@code{LIBS}. Otherwise, require an @code{AC_LIBOBJ} replacement for
@samp{getloadavg} with source code in @file{@var{dir}/getloadavg.c}, and
possibly define several other C preprocessor macros and output
@defmac AC_CHECK_FUNCS (@var{function}@dots{}, @ovar{action-if-found}, @ovar{action-if-not-found})
@acindex{CHECK_FUNCS}
@cvindex HAVE_@var{function}
-For each @var{function} in the blank-or-newline-separated argument list,
-define @code{HAVE_@var{function}} (in all capitals) if it is available.
+For each @var{function} enumerated in the blank-or-newline-separated argument
+list, define @code{HAVE_@var{function}} (in all capitals) if it is available.
If @var{action-if-found} is given, it is additional shell code to
execute when one of the functions is found. You can give it a value of
@samp{break} to break out of the loop on the first match. If
@code{"foo"} or @code{"bar"}, you should do:
@example
-AC_LIBSOURCE(foo.c)
-AC_LIBSOURCE(bar.c)
-AC_LIBOBJ($foo_or_bar)
+AC_LIBSOURCE([foo.c])
+AC_LIBSOURCE([bar.c])
+AC_LIBOBJ([$foo_or_bar])
@end example
@noindent
@example
AC_LIBSOURCES([foo.c, bar.c])
-AC_LIBOBJ($foo_or_bar)
+AC_LIBOBJ([$foo_or_bar])
@end example
@end defmac
@var{directory}, a name relative to the top level of the
source tree. The replacement directory defaults to @file{.}, the top
level directory, and the most typical value is @file{lib}, corresponding
-to @samp{AC_CONFIG_LIBOBJ_DIR(lib)}.
+to @samp{AC_CONFIG_LIBOBJ_DIR([lib])}.
@command{configure} might need to know the replacement directory for the
following reasons: (i) some checks use the replacement files, (ii) some
@example
AC_HEADER_STDC
-AC_CHECK_FUNCS(strchr memcpy)
+AC_CHECK_FUNCS([strchr memcpy])
@end example
@noindent
way to incorporate your implementations only when needed (since the ones
in system C libraries may be hand optimized) is to, taking @code{memchr}
for example, put it in @file{memchr.c} and use
-@samp{AC_REPLACE_FUNCS(memchr)}.
+@samp{AC_REPLACE_FUNCS([memchr])}.
@end defmac
@defmac AC_HEADER_SYS_WAIT
example, @code{struct timeval} as well as
@code{struct tm}. It is best used in conjunction with
@code{HAVE_SYS_TIME_H}, which can be checked for using
-@code{AC_CHECK_HEADERS(sys/time.h)}.
+@code{AC_CHECK_HEADERS([sys/time.h])}.
@example
@group
This macro uses an m4 list as first argument:
@example
-AC_CHECK_DECLS(strdup)
+AC_CHECK_DECLS([strdup])
AC_CHECK_DECLS([strlen])
AC_CHECK_DECLS([malloc, realloc, calloc, free])
@end example
(@pxref{Default Includes}).
@example
-AC_CHECK_MEMBER(struct passwd.pw_gecos,,
+AC_CHECK_MEMBER([struct passwd.pw_gecos], [],
[AC_MSG_ERROR([We need `passwd.pw_gecos'!])],
[#include <pwd.h>])
@end example
@defmac AC_TYPE_MODE_T
@acindex{TYPE_MODE_T}
@cvindex mode_t
-Equivalent to @samp{AC_CHECK_TYPE(mode_t, int)}.
+Equivalent to @samp{AC_CHECK_TYPE([mode_t], [int])}.
@end defmac
@defmac AC_TYPE_OFF_T
@acindex{TYPE_OFF_T}
@cvindex off_t
-Equivalent to @samp{AC_CHECK_TYPE(off_t, long int)}.
+Equivalent to @samp{AC_CHECK_TYPE([off_t], [long int])}.
@end defmac
@defmac AC_TYPE_PID_T
@acindex{TYPE_PID_T}
@cvindex pid_t
-Equivalent to @samp{AC_CHECK_TYPE(pid_t, int)}.
+Equivalent to @samp{AC_CHECK_TYPE([pid_t], [int])}.
@end defmac
@defmac AC_TYPE_SIGNAL
@defmac AC_TYPE_SIZE_T
@acindex{TYPE_SIZE_T}
@cvindex size_t
-Equivalent to @samp{AC_CHECK_TYPE(size_t, unsigned int)}.
+Equivalent to @samp{AC_CHECK_TYPE([size_t], [unsigned int])}.
@end defmac
@defmac AC_TYPE_UID_T
This macro uses m4 lists:
@example
-AC_CHECK_TYPES(ptrdiff_t)
+AC_CHECK_TYPES([ptrdiff_t])
AC_CHECK_TYPES([unsigned long long int, uintmax_t])
@end example
@noindent
To our knowledge, there is a single compiler that does not support this
trick: the HP C compilers (the real one, not only the ``bundled'') on
-HP-UX 11.00:
-
-@example
-$ @kbd{cc -c -Ae +O2 +Onolimit conftest.c}
-cc: "conftest.c": error 1879: Variable-length arrays cannot \
- have static storage.
-@end example
-
+HP-UX 11.00. They incorrectly reject the above program with the diagnostic
+``Variable-length arrays cannot have static storage.''
+This bug comes from HP compilers' mishandling of @code{sizeof (int)},
+not from the @code{? 1 : -1}, and
Autoconf works around this problem by casting @code{sizeof (int)} to
@code{long int} before comparing it.
@end table
For example, the call
@example
-AC_CHECK_SIZEOF(int *)
+AC_CHECK_SIZEOF([int *])
@end example
@noindent
@table @asis
@item Don't use lines containing solitary backslashes
They tickle a bug in the HP-UX C compiler (checked on HP-UX 10.20,
-11.00, and 11i). Running the compiler on the following source,
+11.00, and 11i). When given the following source:
@example
#ifdef __STDC__
@end example
@noindent
-yields
-
-@example
-@error{}cpp: "foo.c", line 13: error 4048: Non-terminating comment at end of file.
-@error{}cpp: "foo.c", line 13: error 4033: Missing #endif at end of file.
-@end example
-
-@noindent
+the compiler incorrectly fails with the diagnostics ``Non-terminating
+comment at end of file'' and ``Missing @samp{#endif} at end of file.''
Removing the lines with solitary backslashes solves the problem.
@item Don't compile several files at once if output matters to you
this:
@example
-AC_PROG_CC(cl egcs gcc cc)
+AC_PROG_CC([cl egcs gcc cc])
@end example
If the C compiler is not in @acronym{ANSI} mode by default, try to add an
like this:
@example
-AC_PROG_CXX(cl KCC CC cxx cc++ xlC aCC c++ g++ egcs gcc)
+AC_PROG_CXX([cl KCC CC cxx cc++ xlC aCC c++ g++ egcs gcc])
@end example
If using the @acronym{GNU} C++ compiler, set shell variable @code{GXX} to
@code{AC_PROG_F77} like this:
@example
-AC_PROG_F77(fl32 f77 fort77 xlf g77 f90 xlf90)
+AC_PROG_F77([fl32 f77 fort77 xlf g77 f90 xlf90])
@end example
If using @code{g77} (the @acronym{GNU} Fortran 77 compiler), then
To check for characteristics not listed here, use
@code{AC_COMPILE_IFELSE} (@pxref{Running the Compiler}) or
@code{AC_RUN_IFELSE} (@pxref{Run Time}), making sure to first set the
-current language to Fortran 77 or Fortran via @code{AC_LANG(Fortran 77)}
+current language to Fortran 77 or Fortran via @code{AC_LANG([Fortran 77])}
or @code{AC_LANG(Fortran)} (@pxref{Language Choice}).
@defmac AC_SYS_INTERPRETER
@acindex{SYS_INTERPRETER}
Check whether the system supports starting scripts with a line of the
-form @samp{#! /bin/csh} to select the interpreter to use for the script.
+form @samp{#!/bin/sh} to select the interpreter to use for the script.
After running this macro, shell code in @file{configure.ac} can check
the shell variable @code{interpval}; it will be set to @samp{yes}
if the system supports @samp{#!}, @samp{no} if not.
case@dots{}), since Autoconf will detect inconsistencies.
@example
-AC_LANG_PUSH(Fortran 77)
+AC_LANG_PUSH([Fortran 77])
# Perform some tests on Fortran 77.
# @dots{}
-AC_LANG_POP(Fortran 77)
+AC_LANG_POP([Fortran 77])
@end example
@end defmac
For instance executing (observe the double quotation!):
@example
-AC_INIT(Autoconf Documentation, @value{VERSION}, bug-autoconf@@gnu.org)
+AC_INIT([Hello], [1.0], [bug-hello@@example.org])
AC_DEFINE([HELLO_WORLD], ["Hello, World\n"],
[Greetings string.])
AC_LANG_CONFTEST(
results in:
@example
+@dots{}
# 1 "conftest.c"
-# 1169 "configure"
-# 1 "confdefs.h" 1
-
-#define PACKAGE_NAME "Autoconf Documentation"
-#define PACKAGE_TARNAME "autoconf-documentation"
-#define PACKAGE_VERSION "@value{VERSION}"
-#define PACKAGE_STRING "Autoconf Documentation @value{VERSION}"
-#define PACKAGE_BUGREPORT "bug-autoconf@@gnu.org"
+#define PACKAGE_NAME "Hello"
+#define PACKAGE_TARNAME "hello"
+#define PACKAGE_VERSION "1.0"
+#define PACKAGE_STRING "Hello 1.0"
+#define PACKAGE_BUGREPORT "bug-hello@@example.org"
#define HELLO_WORLD "Hello, World\n"
-# 1170 "configure" 2
const char hw[] = "Hello, World\n";
@end example
For instance:
@example
-AC_INIT(Autoconf Documentation, @value{VERSION}, bug-autoconf@@gnu.org)
+AC_INIT([Hello], [1.0], [bug-hello@@example.org])
AC_DEFINE([HELLO_WORLD], ["Hello, World\n"],
[Greetings string.])
AC_LANG_CONFTEST(
results in:
@example
+@dots{}
# 1 "conftest.c"
-# 1169 "configure"
-# 1 "confdefs.h" 1
-
-#define PACKAGE_NAME "Autoconf Documentation"
-#define PACKAGE_TARNAME "autoconf-documentation"
-#define PACKAGE_VERSION "@value{VERSION}"
-#define PACKAGE_STRING "Autoconf Documentation @value{VERSION}"
-#define PACKAGE_BUGREPORT "bug-autoconf@@gnu.org"
+#define PACKAGE_NAME "Hello"
+#define PACKAGE_TARNAME "hello"
+#define PACKAGE_VERSION "1.0"
+#define PACKAGE_STRING "Hello 1.0"
+#define PACKAGE_BUGREPORT "bug-hello@@example.org"
#define HELLO_WORLD "Hello, World\n"
-# 1170 "configure" 2
const char hw[] = "Hello, World\n";
int
For instance:
@example
-AC_INIT(Autoconf Documentation, @value{VERSION}, bug-autoconf@@gnu.org)
+AC_INIT([Hello], [1.0], [bug-hello@@example.org])
AC_DEFINE([HELLO_WORLD], ["Hello, World\n"],
[Greetings string.])
AC_PREPROC_IFELSE(
@example
checking for gcc... gcc
-checking for C compiler default output... a.out
+checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
-checking for gcc option to accept ANSI C... none needed
+checking for gcc option to accept ISO C89... none needed
checking how to run the C preprocessor... gcc -E
OK
@end example
@item Tru64
@cindex Tru64
-The @uref{http://h30097.www3.hp.com/docs/,
-documentation of several versions of Tru64} is available in different
+@uref{http://h30097.www3.hp.com/docs/,
+Documentation of several versions of Tru64} is available in different
formats.
@item Unix version 7
# The order of these tests is important.
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/statvfs.h>
#include <sys/fstyp.h>]])],
- [AC_DEFINE(FSTYPE_STATVFS, 1,
+ [AC_DEFINE([FSTYPE_STATVFS], [1],
[Define if statvfs exists.])
fstype=SVR4])
if test $fstype = no; then
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/statfs.h>
#include <sys/fstyp.h>]])],
- [AC_DEFINE(FSTYPE_USG_STATFS, 1,
+ [AC_DEFINE([FSTYPE_USG_STATFS], [1],
[Define if USG statfs.])
fstype=SVR3])
fi
if test $fstype = no; then
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/statfs.h>
#include <sys/vmount.h>]])]),
- [AC_DEFINE(FSTYPE_AIX_STATFS, 1,
+ [AC_DEFINE([FSTYPE_AIX_STATFS], [1],
[Define if AIX statfs.])
fstype=AIX])
fi
appropriate cache variable, as in this example:
@example
-AC_CHECK_FUNC(vprintf, [AC_DEFINE(HAVE_VPRINTF, 1,
+AC_CHECK_FUNC([vprintf], [AC_DEFINE([HAVE_VPRINTF], [1],
[Define if vprintf exists.])])
if test "$ac_cv_func_vprintf" != yes; then
- AC_CHECK_FUNC(_doprnt, [AC_DEFINE(HAVE_DOPRNT, 1,
+ AC_CHECK_FUNC([_doprnt], [AC_DEFINE([HAVE_DOPRNT], [1],
[Define if _doprnt exists.])])
fi
@end example
@code{EQUATION} to be the string constant @samp{"$a > $b"}:
@example
-AC_DEFINE(EQUATION, "$a > $b",
+AC_DEFINE([EQUATION], ["$a > $b"],
[Equation string.])
@end example
@var{variable} or @var{value} is a shell variable. Examples:
@example
-AC_DEFINE_UNQUOTED(config_machfile, "$machfile",
+AC_DEFINE_UNQUOTED([config_machfile], ["$machfile"],
[Configuration machine file.])
-AC_DEFINE_UNQUOTED(GETGROUPS_T, $ac_cv_type_getgroups,
+AC_DEFINE_UNQUOTED([GETGROUPS_T], [$ac_cv_type_getgroups],
[getgroups return type.])
-AC_DEFINE_UNQUOTED($ac_tr_hdr, 1,
+AC_DEFINE_UNQUOTED([$ac_tr_hdr], [1],
[Translated header name.])
@end example
@end defmac
newlines. That is, do this:
@example
-AC_CHECK_HEADER(elf.h,
- [AC_DEFINE(SVR4, 1, [System V Release 4]) LIBS="$LIBS -lelf"])
+AC_CHECK_HEADER([elf.h],
+ [AC_DEFINE([SVR4], [1], [System V Release 4]) LIBS="$LIBS -lelf"])
@end example
@noindent
or this:
@example
-AC_CHECK_HEADER(elf.h,
- [AC_DEFINE(SVR4, 1, [System V Release 4])
+AC_CHECK_HEADER([elf.h],
+ [AC_DEFINE([SVR4], [1], [System V Release 4])
LIBS="$LIBS -lelf"])
@end example
instead of this:
@example
-AC_CHECK_HEADER(elf.h,
- [AC_DEFINE(SVR4, 1, [System V Release 4]); LIBS="$LIBS -lelf"])
+AC_CHECK_HEADER([elf.h],
+ [AC_DEFINE([SVR4], [1], [System V Release 4]); LIBS="$LIBS -lelf"])
@end example
@node Setting Output Variables
[ac_cv_shell_true_works=no
true && ac_cv_shell_true_works=yes
if test $ac_cv_shell_true_works = yes; then
- AC_DEFINE([TRUE_WORKS], 1
+ AC_DEFINE([TRUE_WORKS], [1],
[Define if `true(1)' works properly.])
fi])
])
[ac_cv_shell_true_works=no
true && ac_cv_shell_true_works=yes])
if test $ac_cv_shell_true_works = yes; then
- AC_DEFINE([TRUE_WORKS], 1
+ AC_DEFINE([TRUE_WORKS], [1],
[Define if `true(1)' works properly.])
fi
])
and configure runs. It is not useful on other systems. If its contents
are invalid for some reason, the user may delete or edit it.
-By default, @command{configure} uses no cache file (technically, it uses
-@option{--cache-file=/dev/null}), to avoid problems caused by accidental
+By default, @command{configure} uses no cache file,
+to avoid problems caused by accidental
use of stale cache files.
To enable caching, @command{configure} accepts @option{--config-cache} (or
@group
# Checks for libraries.
-AC_CHECK_LIB(nsl, gethostbyname)
-AC_CHECK_LIB(socket, connect)
+AC_CHECK_LIB([nsl], [gethostbyname])
+AC_CHECK_LIB([socket], [connect])
@r{ @dots{} more lib checks @dots{}}
AC_CACHE_SAVE
@end group
@group
# Might abort@dots{}
-AM_PATH_GTK(1.0.2,, [AC_MSG_ERROR([GTK not in path])])
-AM_PATH_GTKMM(0.9.5,, [AC_MSG_ERROR([GTK not in path])])
+AM_PATH_GTK([1.0.2], [], [AC_MSG_ERROR([GTK not in path])])
+AM_PATH_GTKMM([0.9.5], [], [AC_MSG_ERROR([GTK not in path])])
@end group
@r{ @dots{} AC_OUTPUT, etc. @dots{}}
@end example
@end example
@noindent
-If you want to disable @command{autom4te}'s defaults and
-@env{WARNINGS}, but (for example) enable the warnings about obsolete
+For example, if you want to disable @command{autom4te}'s defaults and
+@env{WARNINGS}, but enable the warnings about obsolete
constructs, you would use @option{-W none,obsolete}.
@cindex Back trace
@cindex Macro invocation stack
@command{autom4te} displays a back trace for errors, but not for
-warnings; if you want them, just pass @option{-W error}. For instance,
-on this @file{configure.ac}:
-
-@example
-AC_DEFUN([INNER],
-[AC_RUN_IFELSE([AC_LANG_PROGRAM([exit (0)])])])
-
-AC_DEFUN([OUTER],
-[INNER])
-
-AC_INIT
-OUTER
-@end example
-
-@noindent
-you get:
-
-@example
-$ @kbd{autom4te -l autoconf -Wcross}
-configure.ac:8: warning: AC_RUN_IFELSE called without default \
-to allow cross compiling
-$ @kbd{autom4te -l autoconf -Wcross,error -f}
-configure.ac:8: error: AC_RUN_IFELSE called without default \
-to allow cross compiling
-acgeneral.m4:3044: AC_RUN_IFELSE is expanded from...
-configure.ac:2: INNER is expanded from...
-configure.ac:5: OUTER is expanded from...
-configure.ac:8: the top level
-@end example
-
+warnings; if you want them, just pass @option{-W error}.
@item --melt
@itemx -m
@cindex @file{autom4te.cfg}
As an example, if Autoconf is installed in its default location,
-@file{/usr/local}, running @samp{autom4te -l m4sugar foo.m4} is
-strictly equivalent to running @samp{autom4te --prepend-include
-/usr/local/share/autoconf m4sugar/m4sugar.m4f --warnings syntax foo.m4}.
-Recursive expansion applies: running @samp{autom4te -l m4sh foo.m4}
+@file{/usr/local}, the command @samp{autom4te -l m4sugar foo.m4} is
+strictly equivalent to the command:
+
+@example
+autom4te --prepend-include /usr/local/share/autoconf \
+ m4sugar/m4sugar.m4f --warnings syntax foo.m4
+@end example
+
+@noindent
+Recursive expansion applies here: the command @samp{autom4te -l m4sh foo.m4}
is the same as @samp{autom4te --language M4sugar m4sugar/m4sh.m4f
-foo.m4}, i.e., @samp{autom4te --prepend-include /usr/local/share/autoconf
-m4sugar/m4sugar.m4f m4sugar/m4sh.m4f --mode 777 foo.m4}. The definition
-of the languages is stored in @file{autom4te.cfg}.
+foo.m4}, i.e.:
+
+@example
+autom4te --prepend-include /usr/local/share/autoconf \
+ m4sugar/m4sugar.m4f m4sugar/m4sh.m4f --mode 777 foo.m4
+@end example
+
+@noindent
+The definition of the languages is stored in @file{autom4te.cfg}.
@node Customizing autom4te
@subsection Customizing @command{autom4te}
@defmac AS_IF (@var{test}, @ovar{RUN-IF-TRUE}, @ovar{RUN-IF-FALSE})
@asindex{IF}
-Run shell code TEST. If TEST exits with a zero status then run shell code
+Run shell code TEST@. If TEST exits with a zero status then run shell code
RUN-IF-TRUE, else run shell code RUN-IF-FALSE, with simplifications if either
RUN-IF-TRUE or RUN-IF-FALSE is empty.
@end defmac
# AC_MSG_ERROR(ERROR, [EXIT-STATUS = 1])
# --------------------------------------
m4_define([AC_MSG_ERROR],
-[@{ _AC_ECHO([configure: error: $1], 2); exit m4_default([$2], 1); @}])
+ [@{ AS_MESSAGE([error: $1], [2])
+ exit m4_default([$2], [1]); @}])
@end example
Comments about the macro should be left in the header comment. Most
with this @file{configure.ac}
@example
-AC_INIT
+AC_INIT([Dance Manager], [1.0], [bug-dance@@example.org])
RESERVE_DANCE_FLOOR
if test "$dance_floor" = occupied; then
AC_MSG_ERROR([cannot pick up here, let's move])
You should not use shell functions, aliases, negated character
classes, or other features that are not found in all Bourne-compatible
shells; restrict yourself to the lowest common denominator. Even
-@code{unset} is not supported by all shells! Also, include a space
-after the exclamation point in interpreter specifications, like this:
-
-@example
-#! /usr/bin/perl
-@end example
+@code{unset} is not supported by all shells!
-@noindent
-If you omit the space before the absolute file name,
-then 4.2@acronym{BSD} based systems
-(such as DYNIX) will ignore the line, because they interpret
-@samp{#! /} as a 4-byte magic number. Some old systems have quite
-small limits on the length of the @samp{#!} line too, for instance 32
+Some old systems have quite
+small limits on the length of the @samp{#!} line; for instance, 32
bytes (not including the newline) on SunOS 4.
+A few ancient 4.2@acronym{BSD} based systems (such as Dynix circa 1984)
+required a single space between the @samp{#!} and the @samp{/}, but
+these are no longer of practical concern.
The set of external programs you should run in a @command{configure} script
is fairly small. @xref{Utilities in Makefiles,, Utilities in
release. It is usually called @command{ksh}, but is called @command{sh}
on some hosts if you set your path appropriately.
-@itemize @minus
-@item
Solaris systems have three variants:
@prindex @command{/usr/bin/ksh} on Solaris
-@command{/usr/bin/ksh} is @samp{ksh88},
+@command{/usr/bin/ksh} is @samp{ksh88}; it is
+standard on Solaris 2.0 and later.
@prindex @command{/usr/xpg4/bin/sh} on Solaris
@command{/usr/xpg4/bin/sh} is a Posix-compliant variant of
-@samp{ksh88}, and
+@samp{ksh88}; it is standard on Solaris 9 and later.
@prindex @command{/usr/dt/bin/dtksh} on Solaris
-@command{/usr/dt/bin/dtksh} is @samp{ksh93}. @command{/usr/bin/ksh}
-is standard on Solaris; the other variants are parts of optional
+@command{/usr/dt/bin/dtksh} is @samp{ksh93}.
+Variants that are not standard may be parts of optional
packages. There is no extra charge for these packages, but they are
not part of a minimal OS install and therefore some installations may
not have it.
-@item
Starting with Tru64 Version 4.0, the Korn shell @command{/usr/bin/ksh}
is also available as @command{/usr/bin/posix/sh}. If the environment
variable @env{BIN_SH} is set to @code{xpg4}, subsidiary invocations of
the standard shell conform to Posix.
-@end itemize
-
@item Pdksh
@prindex @samp{pdksh}
A public-domain clone of the Korn shell called @command{pdksh} is widely
such code, e.g.:
@example
-cmp file1 file2 >/dev/null 2>&1 || echo files differ or trouble
+cmp file1 file2 >/dev/null 2>&1 ||
+ echo files differ or trouble
@end example
More generally, one can always rewrite @samp{! @var{command}} as:
variable. The following code demonstrates this failure:
@example
-#! /bin/sh
+#!/bin/sh
echo $FOO
FOO=bar
echo $FOO
expressions and literal strings in the program to 399.
Some @command{awk}, such as Solaris 9's native one, have a limit of 99
-fields in a record. You may be able to circumvent this problem by using
+fields in a record. You may be able to circumvent this problem by using
the builtin function @code{split}.
@item @command{cat}
a critical section where neither the old nor the new version of
@file{existing} actually exists.
-Be aware that moving files from @file{/tmp} can sometimes cause
+On some systems moving files from @file{/tmp} can sometimes cause
undesirable (but perfectly valid) warnings, even if you created these
-files. On some systems, creating the file in @file{/tmp} is setting a
-guid @code{wheel} which you may not be part of. So the file is copied,
-and then the @code{chgrp} fails:
+files. This is because @file{/tmp} belongs to a group that ordinary
+users are not members of, and files created in @file{/tmp} inherit
+@file{/tmp}'s group. When the file is copied, @command{mv} issues
+a diagnostic without failing:
-@example
+@smallexample
$ @kbd{touch /tmp/foo}
$ @kbd{mv /tmp/foo .}
-@error{}mv: ./foo: set owner/group (was: 3830/0): Operation not permitted
+@error{}mv: ./foo: set owner/group (was: 100/0): Operation not permitted
$ @kbd{echo $?}
0
$ @kbd{ls foo}
foo
-@end example
+@end smallexample
@noindent
-This behavior conforms to Posix:
-
-@quotation
-If the duplication of the file characteristics fails for any reason, mv
-shall write a diagnostic message to standard error, but this failure
-shall not cause mv to modify its exit status.''
-@end quotation
+This annoying behavior conforms to Posix, unfortunately.
Moving directories across mount points is not portable, use @command{cp}
and @command{rm}.
OSF/1 4.0d's @command{make} cannot process @file{Makefile}s with lines
longer than 38912 bytes. It exits with a @code{Line too long}
diagnostic. A later version, Tru64 5.1's @command{make} has been
-reported to crash with lines around 20KB.
+reported to crash with lines around 20 kB.
@item @code{make macro=value} and sub-@command{make}s.
sub-@code{make}s as expected.
This syntax (@code{foo=bar make -e}) is portable only when used
-outside a @file{Makefile}, for instance from a script or from the
+outside of a @file{Makefile}, for instance from a script or from the
command line. When run inside a @command{make} rule, GNU
@command{make} 3.80 and prior versions forget to propagate the
@code{-e} option to sub-@command{make}s.
@example
VPATH = ../pkg/src
-foo.c: ifoo.c
- cp `test -f ifoo.c || echo ../pkg/src/`ifoo.c foo.c
+f.c: if.c
+ cp `test -f if.c || echo $(VPATH)/`if.c f.c
@end example
@item Automatic rule rewriting
@example
VPATH = ../pkg/src
-foo.c: ifoo.c
- cp ifoo.c foo.c
+f.c: if.c
+ cp if.c f.c
@end example
@noindent
-would execute @code{cp ../pkg/src/ifoo.c foo.c} if @file{ifoo.c} was
+would execute @code{cp ../pkg/src/if.c f.c} if @file{if.c} was
found in @file{../pkg/src}. That sounds great.
However, for the sake of other @command{make} implementations, we can't
rely on this, and we have to search @code{VPATH} manually:
-@example
+@smallexample
VPATH = ../pkg/src
-foo.c: ifoo.c
- cp `test -f ifoo.c || echo ../pkg/src/`ifoo.c foo.c
-@end example
+f.c: if.c
+ cp `test -f if.c || echo $(VPATH)/`if.c f.c
+@end smallexample
@noindent
However the "prerequisite rewriting" still applies here. So if
-@file{ifoo.c} is in @file{../pkg/src}, SunOS @command{make} and OSF1/Tru64
+@file{if.c} is in @file{../pkg/src}, SunOS @command{make} and OSF1/Tru64
@command{make} will execute
-@example
-@code{cp `test -f ../pkg/src/ifoo.c || echo ../pkg/src/`ifoo.c foo.c}
-@end example
+@smallexample
+@code{cp `test -f ../pkg/src/if.c || echo ../pkg/src/`if.c f.c}
+@end smallexample
@noindent
which reduces to
@example
-cp ifoo.c foo.c
+cp if.c f.c
@end example
@noindent
and thus fails. Oops.
-One workaround is to make sure that ifoo.c never appears as a plain word
+One workaround is to make sure that @file{if.c} never appears as a plain word
in the rule. For instance these three rules would be safe.
-@example
+@smallexample
VPATH = ../pkg/src
-foo.c: ifoo.c
- cp `test -f ./ifoo.c || echo ../pkg/src/`ifoo.c foo.c
-foo2.c: ifoo2.c
- cp `test -f 'ifoo2.c' || echo ../pkg/src/`ifoo2.c foo2.c
-foo3.c: ifoo3.c
- cp `test -f "ifoo3.c" || echo ../pkg/src/`ifoo3.c foo3.c
-@end example
+f.c: if.c
+ cp `test -f ./if.c || echo $(VPATH)/`if.c f.c
+g.c: ig.c
+ cp `test -f 'ig.c' || echo $(VPATH)/`ig.c g.c
+h.c: ih.c
+ cp `test -f "ih.c" || echo $(VPATH)/`ih.c h.c
+@end smallexample
Things get worse when your prerequisites are in a macro.
@example
VPATH = ../pkg/src
-HEADERS = foo.h foo2.h foo3.h
+HEADERS = f.h g.h h.h
install-HEADERS: $(HEADERS)
for i in $(HEADERS); do \
- $(INSTALL) -m 644 `test -f $$i || echo ../pkg/src/`$$i \
+ $(INSTALL) -m 644 \
+ `test -f $$i || echo $(VPATH)/`$$i \
$(DESTDIR)$(includedir)/$$i; \
done
@end example
The above @code{install-HEADERS} rule is not SunOS-proof because @code{for
-i in $(HEADERS);} will be expanded as @code{for i in foo.h foo2.h foo3.h;}
-where @code{foo.h} and @code{foo2.h} are plain words and are hence
+i in $(HEADERS);} will be expanded as @code{for i in f.h g.h h.h;}
+where @code{f.h} and @code{g.h} are plain words and are hence
subject to @code{VPATH} adjustments.
If the three files are in @file{../pkg/src}, the rule is run as:
@example
-for i in ../pkg/src/foo.h ../pkg/src/foo2.h foo3.h; do \
- install -m 644 `test -f $i || echo ../pkg/src/`$i \
+for i in ../pkg/src/f.h ../pkg/src/g.h h.h; do \
+ install -m 644 \
+ `test -f $i || echo ../pkg/src/`$i \
/usr/local/include/$i; \
done
@end example
where the two first @command{install} calls will fail. For instance,
-consider the @code{foo.h} installation:
+consider the @code{f.h} installation:
@example
-install -m 644 `test -f ../pkg/src/foo.h || echo ../pkg/src/`../pkg/src/foo.h \
- /usr/local/include/../pkg/src/foo.h;
+install -m 644 \
+ `test -f ../pkg/src/f.h || \
+ echo ../pkg/src/ \
+ `../pkg/src/f.h \
+ /usr/local/include/../pkg/src/f.h;
@end example
@noindent
It reduces to:
@example
-install -m 644 ../pkg/src/foo.h /usr/local/include/../pkg/src/foo.h;
+install -m 644 \
+ ../pkg/src/f.h \
+ /usr/local/include/../pkg/src/f.h;
@end example
Note that the manual @code{VPATH} search did not cause any problems here;
-however this command installs @file{foo.h} in an incorrect directory.
+however this command installs @file{f.h} in an incorrect directory.
Trying to quote @code{$(HEADERS)} in some way, as we did for
@code{foo.c} a few @file{Makefile}s ago, does not help:
@example
install-HEADERS: $(HEADERS)
- headers='$(HEADERS)'; for i in $$headers; do \
- $(INSTALL) -m 644 `test -f $$i || echo ../pkg/src/`$$i \
+ headers='$(HEADERS)'; \
+ for i in $$headers; do \
+ $(INSTALL) -m 644 \
+ `test -f $$i || echo $(VPATH)/`$$i \
$(DESTDIR)$(includedir)/$$i; \
done
@end example
-Indeed, @code{headers='$(HEADERS)'} expands to @code{headers='foo.h
-foo2.h foo3.h'} where @code{foo2.h} is still a plain word. (Aside: the
-@code{headers='$(HEADERS)'; for i in $$headers;} idiom is a good
+Now, @code{headers='$(HEADERS)'} macroexpands to:
+
+@example
+headers='f.h g.h h.h'
+@end example
+
+@noindent
+but @code{g.h} is still a plain word. (As an aside, the idiom
+@code{headers='$(HEADERS)'; for i in $$headers;} is a good
idea if @code{$(HEADERS)} can be empty, because some shells diagnose a
syntax error on @code{for i in;}.)
One workaround is to strip this unwanted @file{../pkg/src/} prefix manually:
@example
VPATH = ../pkg/src
-HEADERS = foo.h foo2.h foo3.h
+HEADERS = f.h g.h h.h
install-HEADERS: $(HEADERS)
- headers='$(HEADERS)'; for i in $$headers; do \
- i=`expr "$$i" : '../pkg/src/\(.*\)'`;
- $(INSTALL) -m 644 `test -f $$i || echo ../pkg/src/`$$i \
+ headers='$(HEADERS)'; \
+ for i in $$headers; do \
+ i=`expr "$$i" : '$(VPATH)/\(.*\)'`;
+ $(INSTALL) -m 644 \
+ `test -f $$i || echo $(VPATH)/`$$i \
$(DESTDIR)$(includedir)/$$i; \
done
@end example
Automake does something similar. However the above hack works only if
the files listed in @code{HEADERS} are in the current directory or a
subdirectory; they should not be in an enclosing directory. If we had
-@code{HEADERS = ../foo.h}, the above fragment would fail in a VPATH
+@code{HEADERS = ../f.h}, the above fragment would fail in a VPATH
build with OSF1/Tru64 @command{make}. The reason is that not only does
OSF1/Tru64 @command{make} rewrite dependencies, but it also simplifies
-them. Hence @code{../foo.h} will become @code{../pkg/foo.h} instead of
-@code{../pkg/src/../foo.h}. This obviously defeats any attempt to strip
+them. Hence @code{../f.h} will become @code{../pkg/f.h} instead of
+@code{../pkg/src/../f.h}. This obviously defeats any attempt to strip
a leading @file{../pkg/src/} component.
The following example makes the behavior of OSF1/Tru64 @command{make}
directory does not even exist, this just means that the simplification
occurred before the file was checked for.)
-For the records here is how SunOS @command{make} behaves on this
+For the record here is how SunOS @command{make} behaves on this
very same example.
-@example
+@smallexample
% make
make: Fatal error: Don't know how to make target `../foo'
% mkdir sub
% make
echo sub/../foo
sub/../foo
-@end example
+@end smallexample
@item OSF/Tru64 @command{make} creates prerequisite directories magically
i?86-*-*) CYCLE_OBJ=rdtsc.o ;;
*) CYCLE_OBJ= ;;
esac
-AC_SUBST(CYCLE_OBJ)
+AC_SUBST([CYCLE_OBJ])
@end example
@code{AC_CONFIG_LINKS} (@pxref{Configuration Links}) is another good way
@example
case $host in
- alpha*-*-*) AC_CONFIG_LINKS(dither.c:alpha/dither.c) ;;
- powerpc*-*-*) AC_CONFIG_LINKS(dither.c:powerpc/dither.c) ;;
- *-*-*) AC_CONFIG_LINKS(dither.c:generic/dither.c) ;;
+ alpha*-*-*) AC_CONFIG_LINKS([dither.c:alpha/dither.c]) ;;
+ powerpc*-*-*) AC_CONFIG_LINKS([dither.c:powerpc/dither.c]) ;;
+ *-*-*) AC_CONFIG_LINKS([dither.c:generic/dither.c]) ;;
esac
@end example
@c FIXME: Remove AS_IF when the problem of AC_REQUIRE within `if' is solved.
@example
-AC_ARG_WITH(readline,
- [AS_HELP_STRING(--with-readline,
+AC_ARG_WITH([readline],
+ [AS_HELP_STRING([--with-readline],
[support fancy command line editing @@<:@@default=check@@:>@@])],
[],
- with_readline=check)
+ [with_readline=check])
LIBREADLINE=
AS_IF([test "x$with_readline" != xno],
- [AC_CHECK_LIB(readline, main,
- [AC_SUBST(LIBREADLINE, "-lreadline -lncurses")
- AC_DEFINE(HAVE_LIBREADLINE, 1, [Define if you have libreadline])
+ [AC_CHECK_LIB([readline], [main],
+ [AC_SUBST([LIBREADLINE], ["-lreadline -lncurses"])
+ AC_DEFINE([HAVE_LIBREADLINE], [1],
+ [Define if you have libreadline])
],
[if test "x$with_readline" != xcheck; then
- AC_MSG_FAILURE([--with-readline was given, but test for readline failed])
+ AC_MSG_FAILURE(
+ [--with-readline was given, but test for readline failed])
fi
], -lncurses)])
@end example
@c FIXME: Remove AS_IF when the problem of AC_REQUIRE within `if' is solved.
@example
-AC_ARG_WITH(readline,
- [AS_HELP_STRING(--with-readline,
+AC_ARG_WITH([readline],
+ [AS_HELP_STRING([--with-readline],
[enable experimental support for readline])],
[],
- with_readline=no)
+ [with_readline=no])
LIBREADLINE=
AS_IF([test "x$with_readline" != xno],
- [AC_CHECK_LIB(readline, main,
- [AC_SUBST(LIBREADLINE, "-lreadline -lncurses")
- AC_DEFINE(HAVE_LIBREADLINE, 1, [Define if you have libreadline])
+ [AC_CHECK_LIB([readline], [main],
+ [AC_SUBST([LIBREADLINE], ["-lreadline -lncurses"])
+ AC_DEFINE([HAVE_LIBREADLINE], [1],
+ [Define if you have libreadline])
],
- [AC_MSG_FAILURE([--with-readline was given, but test for readline failed])],
- -lncurses)])
+ [AC_MSG_FAILURE(
+ [--with-readline was given, but test for readline failed])],
+ [-lncurses])])
@end example
The last example shows how to use @code{AC_ARG_WITH} to give the user the
@c FIXME: Remove AS_IF when the problem of AC_REQUIRE within `if' is solved.
@example
-AC_ARG_WITH(readline,
- [AS_HELP_STRING(--without-readline,
+AC_ARG_WITH([readline],
+ [AS_HELP_STRING([--without-readline],
[disable support for readline])],
[],
- with_readline=yes)
+ [with_readline=yes])
LIBREADLINE=
AS_IF([test "x$with_readline" != xno],
- [AC_CHECK_LIB(readline, main,
- [AC_SUBST(LIBREADLINE, "-lreadline -lncurses")
- AC_DEFINE(HAVE_LIBREADLINE, 1, [Define if you have libreadline])
+ [AC_CHECK_LIB([readline], [main],
+ [AC_SUBST([LIBREADLINE], ["-lreadline -lncurses"])
+ AC_DEFINE([HAVE_LIBREADLINE], [1],
+ [Define if you have libreadline])
],
- [AC_MSG_FAILURE([test for readline failed, use --without-readline if you want to force readline support off])],
- -lncurses)])
+ [AC_MSG_FAILURE(
+ [readline test failed (--without-readline to disable)])],
+ [-lncurses])])
@end example
These three examples can be easily adapted to the case where
Options}). The following example will make this clearer.
@example
-AC_ARG_WITH(foo,
- [AS_HELP_STRING(--with-foo,
+AC_ARG_WITH([foo],
+ [AS_HELP_STRING([--with-foo],
[use foo (default is no)])],
[ac_cv_use_foo=$withval],
[ac_cv_use_foo=no])
This macro is equivalent to:
@example
-AC_CHECK_TYPE([@var{type}],,
- [AC_DEFINE_UNQUOTED([@var{type}], [@var{default}],
- [Define to `@var{default}' if
- <sys/types.h> does not define.])])
+AC_CHECK_TYPE([@var{type}], [],
+ [AC_DEFINE_UNQUOTED([@var{type}], [@var{default}],
+ [Define to `@var{default}'
+ if <sys/types.h> does not define.])])
@end example
In order to keep backward compatibility, the two versions of
Same as:
@example
-AC_CHECK_DECLS([sys_siglist],,,
+AC_CHECK_DECLS([sys_siglist], [], [],
[#include <signal.h>
/* NetBSD declares sys_siglist in unistd.h. */
#if HAVE_UNISTD_H
@code{LIBS}. This macro used to be defined as
@example
-AC_CHECK_LIB(seq, getmntent, LIBS="-lseq $LIBS")
+AC_CHECK_LIB([seq], [getmntent], [LIBS="-lseq $LIBS"])
@end example
@noindent
getpwnam)}. Up to Autoconf 2.13, it used to be
@example
-AC_CHECK_LIB(sun, getmntent, LIBS="-lsun $LIBS")
+AC_CHECK_LIB([sun], [getmntent], [LIBS="-lsun $LIBS"])
@end example
@noindent
@example
AC_FUNC_GETMNTENT
-AC_CHECK_LIB(sun, getpwnam)
+AC_CHECK_LIB([sun], [getpwnam])
@end example
@end defmac
@defmac AC_LANG_C
@acindex{LANG_C}
-Same as @samp{AC_LANG(C)}.
+Same as @samp{AC_LANG([C])}.
@end defmac
@defmac AC_LANG_CPLUSPLUS
@acindex{LANG_CPLUSPLUS}
-Same as @samp{AC_LANG(C++)}.
+Same as @samp{AC_LANG([C++])}.
@end defmac
@defmac AC_LANG_FORTRAN77
@acindex{LANG_FORTRAN77}
-Same as @samp{AC_LANG(Fortran 77)}.
+Same as @samp{AC_LANG([Fortran 77])}.
@end defmac
@defmac AC_LANG_RESTORE
is:
@example
-AC_CONFIG_LINKS(host.h:config/$machine.h
- object.h:config/$obj_format.h)
+AC_CONFIG_LINKS([host.h:config/$machine.h
+ object.h:config/$obj_format.h])
@end example
@end defmac
@cvindex NEED_MEMORY_H
Used to define @code{NEED_MEMORY_H} if the @code{mem} functions were
defined in @file{memory.h}. Today it is equivalent to
-@samp{AC_CHECK_HEADERS(memory.h)}. Adjust your code to depend upon
+@samp{AC_CHECK_HEADERS([memory.h])}. Adjust your code to depend upon
@code{HAVE_MEMORY_H}, not @code{NEED_MEMORY_H}; see @ref{Standard
Symbols}.
@end defmac
macro used to do this:
@example
-AC_CHECK_LIB(intl, strftime, LIBS="-lintl $LIBS")
+AC_CHECK_LIB([intl], [strftime], [LIBS="-lintl $LIBS"])
@end example
@noindent
@defmac AC_TRY_COMPILE (@var{includes}, @var{function-body}, @ovar{action-if-found}, @ovar{action-if-not-found})
@acindex{TRY_COMPILE}
-Same as @samp{AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@var{includes}]],
-[[@var{function-body}]])], [@var{action-if-true}],
-[@var{action-if-false}])} (@pxref{Running the Compiler}).
+Same as:
+
+@example
+AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM([[@var{includes}]],
+ [[@var{function-body}]])],
+ [@var{action-if-true}],
+ [@var{action-if-false}])
+@end example
+
+@noindent
+@xref{Running the Compiler}.
This macro double quotes both @var{includes} and @var{function-body}.
@defmac AC_TRY_CPP (@var{input}, @ovar{action-if-true}, @ovar{action-if-false})
@acindex{TRY_CPP}
-Same as @samp{AC_PREPROC_IFELSE([AC_LANG_SOURCE([[@var{input}]])],
-[@var{action-if-true}], [@var{action-if-false}])} (@pxref{Running the
-Preprocessor}).
+Same as:
+
+@example
+AC_PREPROC_IFELSE(
+ [AC_LANG_SOURCE([[@var{input}]])],
+ [@var{action-if-true}],
+ [@var{action-if-false}])
+@end example
+
+@noindent
+@xref{Running the Preprocessor}.
This macro double quotes the @var{input}.
@end defmac
@defmac AC_TRY_LINK (@var{includes}, @var{function-body}, @ovar{action-if-found}, @ovar{action-if-not-found})
@acindex{TRY_LINK}
-Same as @samp{AC_LINK_IFELSE([AC_LANG_PROGRAM([[@var{includes}]],
-[[@var{function-body}]])], [@var{action-if-true}],
-[@var{action-if-false}])} (@pxref{Running the Compiler}).
+Same as:
+
+@example
+AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM([[@var{includes}]],
+ [[@var{function-body}]])],
+ [@var{action-if-true}],
+ [@var{action-if-false}])
+@end example
+
+@noindent
+@xref{Running the Compiler}.
This macro double quotes both @var{includes} and @var{function-body}.
@defmac AC_TRY_RUN (@var{program}, @ovar{action-if-true}, @ovar{action-if-false}, @ovar{action-if-cross-compiling})
@acindex{TRY_RUN}
-Same as @samp{AC_RUN_IFELSE([AC_LANG_SOURCE([[@var{program}]],
-[@var{action-if-true}], [@var{action-if-false}],
-[@var{action-if-cross-compiling}])} (@pxref{Run Time}).
-@end defmac
+Same as:
+@example
+AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[@var{program}]])],
+ [@var{action-if-true}],
+ [@var{action-if-false}],
+ [@var{action-if-cross-compiling}])
+@end example
+
+@noindent
+@xref{Run Time}).
+@end defmac
@defmac AC_UID_T
@acindex{UID_T}
@defmac AC_UNISTD_H
@acindex{UNISTD_H}
-Same as @samp{AC_CHECK_HEADERS(unistd.h)}.
+Same as @samp{AC_CHECK_HEADERS([unistd.h])}.
@end defmac
@defmac AC_USG
@example
AC_MSG_CHECKING([for Xenix])
-AC_EGREP_CPP(yes,
+AC_EGREP_CPP([yes],
[#if defined M_XENIX && !defined M_UNIX
yes
#endif],
Here is a way to write it for version 2:
@example
-AC_CHECK_FUNCS(syslog)
+AC_CHECK_FUNCS([syslog])
if test $ac_cv_func_syslog = no; then
# syslog is not in the default libraries. See if it's in some other.
for lib in bsd socket inet; do
- AC_CHECK_LIB($lib, syslog, [AC_DEFINE(HAVE_SYSLOG)
+ AC_CHECK_LIB([$lib], [syslog], [AC_DEFINE([HAVE_SYSLOG])
LIBS="$LIBS -l$lib"; break])
done
fi
@example
AC_INIT
AC_CHECK_HEADERS(foo.h,,
-AC_MSG_ERROR(cannot find foo.h, bailing out))
+ AC_MSG_ERROR(cannot find foo.h, bailing out))
AC_OUTPUT
@end example
too!
@example
-AC_INIT
-AC_CHECK_HEADERS(foo.h,,
- [AC_MSG_ERROR([cannot find foo.h, bailing out])])
+AC_INIT([Example], [1.0], [bug-example@@example.org])
+AC_CHECK_HEADERS([foo.h], [],
+ [AC_MSG_ERROR([cannot find foo.h, bailing out])])
AC_OUTPUT
@end example
@cindex undefined macro
@cindex @code{_m4_divert_diversion}
-Because Autoconf has been dormant for years, Automake provided
-Autoconf-like macros for a while. Autoconf 2.50 now provides better
+While Autoconf was relatively dormant in the late 1990s, Automake
+provided Autoconf-like macros for a while. Starting with Autoconf 2.50
+in 2001, Autoconf provided
versions of these macros, integrated in the @code{AC_} namespace,
instead of @code{AM_}. But in order to ease the upgrading via
@command{autoupdate}, bindings to such @code{AM_} macros are provided.
-Unfortunately Automake did not quote the names of these macros!
+Unfortunately older versions of Automake (e.g., Automake 1.4)
+did not quote the names of these macros.
Therefore, when @command{m4} finds something like
@samp{AC_DEFUN(AM_TYPE_PTRDIFF_T, @dots{})} in @file{aclocal.m4},
@code{AM_TYPE_PTRDIFF_T} is
complain, in its own words:
@example
-$ @kbd{cat configure.in}
-AC_INIT
+$ @kbd{cat configure.ac}
+AC_INIT([Example], [1.0], [bug-example@@example.org])
AM_TYPE_PTRDIFF_T
$ @kbd{aclocal-1.4}
$ @kbd{autoconf}
-./aclocal.m4:17: error: m4_defn: undefined macro: _m4_divert_diversion
-actypes.m4:289: AM_TYPE_PTRDIFF_T is expanded from...
-./aclocal.m4:17: the top level
+aclocal.m4:17: error: m4_defn: undefined macro: _m4_divert_diversion
+aclocal.m4:17: the top level
+autom4te: m4 failed with exit status: 1
$
@end example
-Future versions of Automake will simply no longer define most of these
+Modern versions of Automake no longer define most of these
macros, and will properly quote the names of the remaining macros.
-But you don't have to wait for it to happen to do the right thing right
-now: do not depend upon macros from Automake as it is simply not its job
+If you must use an old Automake, do not depend upon macros from Automake
+as it is simply not its job
to provide macros (but the one it requires itself):
@example
-$ @kbd{cat configure.in}
-AC_INIT
+$ @kbd{cat configure.ac}
+AC_INIT([Example], [1.0], [bug-example@@example.org])
AM_TYPE_PTRDIFF_T
$ @kbd{rm aclocal.m4}
$ @kbd{autoupdate}
-autoupdate: `configure.in' is updated
-$ @kbd{cat configure.in}
-AC_INIT
+autoupdate: `configure.ac' is updated
+$ @kbd{cat configure.ac}
+AC_INIT([Example], [1.0], [bug-example@@example.org])
AC_CHECK_TYPES([ptrdiff_t])
$ @kbd{aclocal-1.4}
$ @kbd{autoconf}
# the ANSI2KNR-filtering rules.
LIBOBJS=`echo "$LIBOBJS" | sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
LTLIBOBJS=`echo "$LIBOBJS" | sed 's/\.o/\.lo/g'`
-AC_SUBST(LTLIBOBJS)
+AC_SUBST([LTLIBOBJS])
@end example
@noindent
sed 's,\.[[^.]]* ,$U&,g;s,\.[[^.]]*$,$U&,'`
LTLIBOBJS=`echo "$LIB@@&t@@OBJS" |
sed 's,\.[[^.]]* ,.lo ,g;s,\.[[^.]]*$,.lo,'`
-AC_SUBST(LTLIBOBJS)
+AC_SUBST([LTLIBOBJS])
@end example
@sp 1
$(SHELL) $(TESTSUITE) $(TESTSUITEFLAGS)
installcheck-local: atconfig atlocal $(TESTSUITE)
- $(SHELL) $(TESTSUITE) AUTOTEST_PATH="$(bindir)" $(TESTSUITEFLAGS)
+ $(SHELL) $(TESTSUITE) AUTOTEST_PATH="$(bindir)" \
+ $(TESTSUITEFLAGS)
AUTOTEST = $(AUTOM4TE) --language=autotest
$(TESTSUITE): $(srcdir)/testsuite.at
__line__
@end example
-Autoconf requires version 1.4 or above of @acronym{GNU} M4 because it uses
-frozen state files.
+Autoconf requires version 1.4.3 or later of @acronym{GNU} M4.
Since only software maintainers need to use Autoconf, and since @acronym{GNU}
M4 is simple to configure and install, it seems reasonable to require
@example
AC_DEFINE_UNQUOTED([DATADIR], [$datadir],
- [Define to the read-only architecture-independent
- data directory.])
+ [Define to the read-only architecture-independent
+ data directory.])
@end example
@noindent
As of Autoconf 2.56 both checks are performed, and @code{configure}
complains loudly if the compiler and the preprocessor do not agree.
For the time being the result used is that of the preprocessor, to give
-maintainers time to adjust their @file{configure.ac}, but in the near
+maintainers time to adjust their @file{configure.ac}, but in the
future, only the compiler will be considered.
Consider the following example:
-@example
+@smallexample
$ @kbd{cat number.h}
typedef int number;
$ @kbd{cat pi.h}
const number pi = 3;
$ @kbd{cat configure.ac}
-AC_INIT
-AC_CHECK_HEADERS(pi.h)
+AC_INIT([Example], [1.0], [bug-example@@example.org])
+AC_CHECK_HEADERS([pi.h])
$ @kbd{autoconf -Wall}
$ @kbd{./configure}
checking for gcc... gcc
-checking for C compiler default output... a.out
+checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
-checking for gcc option to accept ANSI C... none needed
+checking for gcc option to accept ISO C89... none needed
checking how to run the C preprocessor... gcc -E
+checking for grep that handles long lines and -e... grep
checking for egrep... grep -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking pi.h usability... no
checking pi.h presence... yes
configure: WARNING: pi.h: present but cannot be compiled
-configure: WARNING: pi.h: check for missing prerequisite headers?
+configure: WARNING: pi.h: check for missing prerequisite headers?
+configure: WARNING: pi.h: see the Autoconf documentation
+configure: WARNING: pi.h: section "Present But Cannot Be Compiled"
configure: WARNING: pi.h: proceeding with the preprocessor's result
-configure: WARNING: ## ------------------------------------ ##
-configure: WARNING: ## Report this to bug-autoconf@@gnu.org. ##
-configure: WARNING: ## ------------------------------------ ##
+configure: WARNING: pi.h: in the future, the compiler will take precedence
+configure: WARNING: ## -------------------------------------- ##
+configure: WARNING: ## Report this to bug-example@@example.org ##
+configure: WARNING: ## -------------------------------------- ##
checking for pi.h... yes
-@end example
+@end smallexample
@noindent
The proper way the handle this case is using the fourth argument
@example
$ @kbd{cat configure.ac}
-AC_INIT
-AC_CHECK_HEADERS(number.h pi.h,,,
+AC_INIT([Example], [1.0], [bug-example@@example.org])
+AC_CHECK_HEADERS([number.h pi.h], [], [],
[[#if HAVE_NUMBER_H
# include <number.h>
#endif
projects / thirdparty / autoconf.git / commitdiff
