@c %**start of header
@setfilename autoconf.info
@settitle Autoconf
-@c For double-sided printing, uncomment:
-@c @setchapternewpage odd
-@c %**end of header
-@include version.texi
-
-@iftex
@finalout
-@end iftex
+@setchapternewpage odd
+@setcontentsaftertitlepage
+
+@include version.texi
@c A simple macro for optional variables.
@macro ovar{varname}
@subtitle Creating Automatic Configuration Scripts
@subtitle Edition @value{EDITION}, for Autoconf version @value{VERSION}
@subtitle @value{UPDATED}
-@author by David MacKenzie and Ben Elliston
+@author David MacKenzie and Ben Elliston
@c I think I've rewritten all of Noah and Roland's contributions by now.
@page
* Specifying Names:: Specifying the system type
* Canonicalizing:: Getting the canonical system type
-* System Type Variables:: Variables containing the system type
* Using System Type:: What to do with the system type
Site Configuration
@end example
@noindent
-when run with FOO=foo in the environment, these shells will print
+when run with @samp{FOO=foo} in the environment, these shells will print
alternately @samp{foo} and @samp{bar}, although it should only print
@samp{foo} and then a sequence of @samp{bar}s.
@menu
* Specifying Names:: Specifying the system type
* Canonicalizing:: Getting the canonical system type
-* System Type Variables:: Variables containing the system type
* Using System Type:: What to do with the system type
@end menu
Like other @sc{gnu} @code{configure} scripts, Autoconf-generated
@code{configure} scripts can make decisions based on a canonical name
-for the system type, which has the form:
-
-@example
-@var{cpu}-@var{company}-@var{system}
-@end example
-
-@noindent
-where @var{system} can have one of these forms:
-
-@example
-@var{os}
-@var{kernel}-@var{os}
-@end example
+for the system type, which has the form
+@samp{@var{cpu}-@var{vendor}-@var{os}}, where @var{os} can be
+@samp{@var{system}} or @samp{@var{kernel}-@var{system}}
@code{configure} can usually guess the canonical name for the type of
system it's running on. To do so it runs a script called
@samp{mips-dec-ultrix4.2}. @code{configure} runs a script called
@code{config.sub} to canonicalize system type aliases.
-@node Canonicalizing, System Type Variables, Specifying Names, Manual Configuration
+@node Canonicalizing, Using System Type, Specifying Names, Manual Configuration
@section Getting the Canonical System Type
The following macros make the system type available to @code{configure}
-scripts. They run the shell script @code{config.guess} to determine any
-values for the host, target, and build types that they need and the user
-did not specify on the command line. They run @code{config.sub} to
-canonicalize any aliases the user gave. If you use these macros, you
-must distribute those two shell scripts along with your source code.
-@xref{Output}, for information about the @code{AC_CONFIG_AUX_DIR} macro
-which you can use to control which directory @code{configure} looks for
-those scripts in. If you do not use either of these macros,
-@code{configure} ignores any @option{--host}, @option{--target}, and
-@option{--build} options given to it.
+scripts.
+
+@ovindex build_alias
+@ovindex host_alias
+@ovindex target_alias
+
+The variables @samp{build_alias}, @samp{host_alias}, and
+@samp{target_alias} are always exactly the arguments of @samp{--build},
+@samp{--host}, and @samp{--target}, in particular they are left empty if
+the user did not use them, even if the corresponding @code{AC_CANONICAL}
+macro was run. Any configure script may use these variables anywhere.
+These are the variables which should be used when in interaction with
+the user.
+
+If you need to recognize some special environments based on their system
+type, run the following macros to get canonical system names. These
+variables are not set before the macro call.
+
+If you use these macros, you must distribute @code{config.guess} and
+@code{config.sub} along with your source code. @xref{Output}, for
+information about the @code{AC_CONFIG_AUX_DIR} macro which you can use
+to control which directory @code{configure} looks for those scripts in.
@defmac AC_CANONICAL_BUILD
@maindex CANONICAL_BUILD
-Compute the @samp{build} system type variables, see @ref{System Type
-Variables}. Unless specified to @code{configure} via @option{--build},
-the build system is guessed by running @code{config.guess}.
+@ovindex build
+@ovindex build_cpu
+@ovindex build_vendor
+@ovindex build_os
+Compute the canonical build system type variable, @code{build}, and its
+three individual parts @code{build_cpu}, @code{build_vendor}, and
+@code{build_os}.
+
+If @samp{--build} was specified, then @code{build} is the
+canonicalization of @code{build_alias} by @command{config.sub},
+otherwise it is determined by the shell script @code{config.guess}.
@end defmac
@defmac AC_CANONICAL_HOST
@maindex CANONICAL_HOST
-Compute the @samp{host} system type variables, see @ref{System Type
-Variables}. Unless specified to @code{configure} via @option{--host}, the
-host system is the build system.
+@ovindex host
+@ovindex host_cpu
+@ovindex host_vendor
+@ovindex host_os
+Compute the canonical host system type variable, @code{host}, and its
+three individual parts @code{host_cpu}, @code{host_vendor}, and
+@code{host_os}.
+
+If @samp{--host} was specified, then @code{host} is the
+canonicalization of @code{host_alias} by @command{config.sub},
+otherwise it defaults to @code{build}.
@end defmac
@defmac AC_CANONICAL_TARGET
@maindex CANONICAL_TARGET
-Compute the @samp{target} system type variables, see @ref{System Type
-Variables}. Unless specified to @code{configure} via @option{--target},
-the target system is the host system.
+@ovindex target
+@ovindex target_cpu
+@ovindex target_vendor
+@ovindex target_os
+Compute the canonical target system type variable, @code{target}, and its
+three individual parts @code{target_cpu}, @code{target_vendor}, and
+@code{target_os}.
-This macro only makes sense for compilers, debuggers etc. which might
-run on a machine, but work on binaries from another machine.
+If @samp{--target} was specified, then @code{target} is the
+canonicalization of @code{target_alias} by @command{config.sub},
+otherwise it defaults to @code{host}.
@end defmac
-@defmac AC_VALIDATE_CACHED_SYSTEM_TUPLE (@var{cmd})
+@defmac AC_VALIDATE_CACHED_SYSTEM_TUPLE (@ovar{cmd})
@maindex VALIDATE_CACHED_SYSTEM_TUPLE
If the cache file is inconsistent with the current host, target and
build system types, execute @var{cmd} or print a default error message.
@end defmac
-@node System Type Variables, Using System Type, Canonicalizing, Manual Configuration
-@section System Type Variables
-
-After calling @code{AC_CANONICAL_BUILD}, the following @samp{build}
-output variables contain the build system type information, likewise for
-@code{AC_CANONICAL_HOST} and @code{AC_CANONICAL_TARGET}.
-
-@table @code
-@ovindex build
-@ovindex host
-@ovindex target
-@item @code{build}, @code{host}, @code{target}
-the canonical system names;
-@item @code{build_alias}, @code{host_alias}, @code{target_alias}
-@ovindex build_alias
-@ovindex host_alias
-@ovindex target_alias
-the names the user specified, or the canonical names if
-@code{config.guess} was used;
-@item @code{build_cpu}, @code{build_vendor}, @code{build_os}
-@itemx @code{host_cpu}, @code{host_vendor}, @code{host_os}
-@itemx @code{target_cpu}, @code{target_vendor}, @code{target_os}
-@ovindex build_cpu
-@ovindex host_cpu
-@ovindex target_cpu
-@ovindex build_vendor
-@ovindex host_vendor
-@ovindex target_vendor
-@ovindex build_os
-@ovindex host_os
-@ovindex target_os
-the individual parts of the canonical names (for convenience).
-@end table
-
-
-@node Using System Type, , System Type Variables, Manual Configuration
+@node Using System Type, , Canonicalizing, Manual Configuration
@section Using the System Type
How do you use a canonical system type? Usually, you use it in one or
esac
@end example
+@noindent
and in @file{configure.in}, use:
@example
@defmac AC_CANONICAL_SYSTEM
@maindex CANONICAL_SYSTEM
Determine the system type and set output variables to the names of the
-canonical system types. @xref{System Type Variables}, for details about
-the variables this macro sets.
+canonical system types. @xref{Canonicalizing}, for details about the
+variables this macro sets.
The user is encouraged to explicitly use either
@code{AC_CANONICAL_BUILD}, or @code{AC_CANONICAL_HOST}, or
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