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Diffstat (limited to 'doc/m4.texi')
| -rw-r--r-- | doc/m4.texi | 55 |
1 files changed, 12 insertions, 43 deletions
diff --git a/doc/m4.texi b/doc/m4.texi index e09f3c40..ba1b1576 100644 --- a/doc/m4.texi +++ b/doc/m4.texi @@ -6587,16 +6587,11 @@ could be added only by writing more code in the M4 language, or at the extreme by hacking the sources and recompiling the whole thing to make a custom M4 installation. -Starting with release 2.0, M4 uses Libtool's @code{libltdl} facilities -(@pxref{Using libltdl, , libltdl, libtool, The GNU Libtool Manual}) -to move all of M4's builtins out to pluggable modules. Unless compile -time options are set to change the default build, the installed M4 2.0 -binary is virtually identical to 1.4.x, supporting the same builtins. -However, additional modules can be loaded into the running M4 interpreter -as it is started up at the command line, or during normal expansion of -macros. This facilitates runtime extension of the M4 builtin macro -list using compiled C code linked against a new shared library, -typically named @file{libm4.so}. +Starting with release 2.0, M4 supports and is composed of loadable modules. +Additional modules can be loaded into the running M4 interpreter as it is +started up at the command line, or during normal expansion of macros. This +facilitates runtime extension of the M4 builtin macro list using compiled C +code linked against a new shared library, typically named @file{libm4.so}. For example, you might want to add a @code{setenv} builtin to M4, to use before invoking @code{esyscmd}. We might write a @file{setenv.c} @@ -6655,27 +6650,11 @@ setenv(`PATH', `/sbin:/bin:/usr/sbin:/usr/bin') @result{} @end example -Also, at build time, you can choose which modules to build into -the core (so that they will be available without dynamic loading). -SUSv3 M4 functionality is contained in the module @samp{m4}, GNU -extensions in the module @samp{gnu}, additional module builtins in the -module @samp{load} and so on. - -We hinted earlier that the @code{m4} and @code{gnu} modules are -preloaded into the installed M4 binary, but it is possible to install -a @emph{thinner} binary; for example, omitting the GNU -extensions by configuring the distribution with @kbd{./configure ---with-modules=m4}. For a binary built with that option to understand -code that uses GNU extensions, you must then run @kbd{m4 gnu}. -It is also possible to build a @emph{fatter} binary with additional -modules preloaded: adding, say, the @code{load} module using -@kbd{./configure --with-modules="m4 gnu load"}. - -GNU M4 now has a facility for defining additional builtins without -recompiling the sources. In actual fact, all of the builtins provided -by GNU M4 are loaded from such modules. All of the builtin -descriptions in this manual are annotated with the module from which -they are loaded -- mostly from the module @samp{m4}. +Also, at run time, you can choose which core modules to load. SUSv3 M4 +functionality is contained in the module @samp{m4}, GNU extensions in the +module @samp{gnu}, and so on. All of the builtin descriptions in this manual +are annotated with the module from which they are loaded -- mostly from the +module @samp{m4}. When you start GNU M4, the modules @samp{m4} and @samp{gnu} are loaded by default. If you supply the @option{-G} option at startup, the @@ -6698,8 +6677,8 @@ a module multiple times will not affect the order of this list, the position depends on when the module was @emph{first} loaded. @end deffn -For example, if GNU @code{m4} is started with the -@option{load} module, @code{m4modules} will yield the following: +For example, after GNU @code{m4} is started with no additional modules, +@code{m4modules} will yield the following: @example $ @kbd{m4} @@ -6751,16 +6730,6 @@ Expands to the empty string, as an indication that the @samp{traditional} module is loaded. @end deffn -@item load -This module supplies the builtins for advanced use of modules from within a -GNU @code{m4} program. @xref{Modules}, for more details. The -module also defines the following macro: - -@deffn {Macro (load)} __load__ -Expands to the empty string, as an indication that the @samp{load} -module is loaded. -@end deffn - @item mpeval This module provides the implementation for the experimental @code{mpeval} feature. If the host machine does not have the |