* doc/autoconf.texi (autom4te.cache): New section.

diff --git a/ChangeLog b/ChangeLog
index 2264b643763c5d227cd888dfd1b1ef574b1f5f83..a4dcb79da7e1ffdc1d19ceac142188eb08321b79 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2002-09-28  Akim Demaille  <akim@epita.fr>
+
+       * doc/autoconf.texi (autom4te.cache): New section.
+
 2002-09-28  Akim Demaille  <akim@epita.fr>
 
        * lib/autom4te.in (Autoscan-preselections, Autoreconf-preselections)

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index a6c157491a18e6a2eeb724cb7854cdfad810ce89..d48423fb5e2861f6c7301df483fa0eceff0f5c6d 100644 (file)
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -230,7 +230,7 @@ Existing Tests
 * Declarations::                Declarations that may be missing
 * Structures::                  Structures or members that might be missing
 * Types::                       Types that might be missing
-* Compilers and Preprocessors::  Checks for compiling programs
+* Compilers and Preprocessors::  Checking for compiling programs
 * System Services::             Operating system services
 * UNIX Variants::               Special kludges for specific UNIX variants
 
@@ -289,7 +289,7 @@ Writing Tests
 * Multiple Cases::              Tests for several possible values
 * Language Choice::             Selecting which language to use for testing
 
-Checking Run-Time Behavior
+Checking Run Time Behavior
 
 * Test Programs::               Running test programs
 * Guidelines::                  General rules for writing test programs
@@ -313,11 +313,11 @@ Programming in M4
 * M4 Quotation::                Protecting macros from unwanted expansion
 * Invoking autom4te::           The Autoconf executables backbone
 * Programming in M4sugar::      Convenient pure M4 macros
-* Programming in M4sh::         Common shell constructs
+* Programming in M4sh::         Common shell Constructs
 
 M4 Quotation
 
-* Active Characters::           Characters that change the behavior of m4
+* Active Characters::           Characters that change the behavior of M4
 * One Macro Call::              Quotation and one macro call
 * Quotation and Nested Macros::  Macros calling macros
 * Changequote is Evil::         Worse than INTERCAL: M4 + changequote
@@ -433,6 +433,7 @@ Frequent Autoconf Questions, with answers
 * Bootstrapping::               Autoconf and GNU M4 require each other?
 * Why Not Imake::               Why GNU uses @command{configure} instead of Imake
 * Defining Directories::        Passing @code{datadir} to program
+* autom4te.cache::              What is it?  Can I remove it?
 
 History of Autoconf
 
@@ -13892,6 +13893,7 @@ are addressed.
 * Bootstrapping::               Autoconf and GNU M4 require each other?
 * Why Not Imake::               Why GNU uses @command{configure} instead of Imake
 * Defining Directories::        Passing @code{datadir} to program
+* autom4te.cache::              What is it?  Can I remove it?
 @end menu
 
 @node Distributing
@@ -14136,6 +14138,35 @@ Some macros are already available to address this issue: see
 @end itemize
 
 
+@node autom4te.cache
+@section What is @file{autom4te.cache}?
+
+@display
+What is this directory @file{autom4te.cache}?  Can I safely remove it?
+@end display
+
+In the GNU Build System, @file{configure.ac} plays a central role and is
+read by many tools: @command{autoconf} to create @file{configure},
+@command{autoheader} to create @file{config.h.in}, @command{automake} to
+create @file{Makefile.in}, @command{autoscan} to check the completeness
+of @file{configure.ac}, @command{autoreconf} to check the GNU Build
+System components that are used.  To ``read @file{configure.ac}''
+actually means to compile it with M4, which can be a very long process
+for complex @file{configure.ac}.
+
+This is why all these tools, instead of running directly M4, invoke
+@command{autom4te} (@pxref{Invoking autom4te}) which, while answering to
+a specific demand, stores additional information in
+@file{autom4te.cache} for future runs.  For instance, if you run
+@command{autoconf}, behind the scenes, @command{autom4te} will also
+store information for the other tools, so that when you invoke
+@command{autoheader} or @command{automake} etc., re-processing
+@file{configure.ac} is not needed.  The speed up is frequently of 30,
+and is increasing with the size of @file{configure.ac}.
+
+But it is and remains being simply a cache: you can safely remove it.
+
+
 
 @c ===================================================== History of Autoconf.
 

diff --git a/lib/m4sugar/m4sugar.m4 b/lib/m4sugar/m4sugar.m4
index c2d3f7a82bc7ccb6c68b197fe6482786047cfbed..71451dca0f378f333209874fb0ad253e58bc9b15 100644 (file)
--- a/lib/m4sugar/m4sugar.m4
+++ b/lib/m4sugar/m4sugar.m4
@@ -1202,12 +1202,7 @@ m4_define([_m4_divert(GROW)],       10000)
 # -------------------------
 # The prologue for Autoconf macros.
 m4_define([_m4_defun_pro],
-[m4_expansion_stack_push(m4_defn([m4_location($1)])[: $1 is expanded from...])dnl
-m4_pushdef([_m4_expanding($1)])dnl
-m4_ifdef([_m4_divert_dump],
-         [m4_divert_push(m4_defn([_m4_divert_diversion]))],
-         [m4_copy([_m4_divert_diversion], [_m4_divert_dump])dnl
-m4_divert_push([GROW])])dnl
+[
 ])
 
 
@@ -1216,13 +1211,7 @@ m4_divert_push([GROW])])dnl
 # The Epilogue for Autoconf macros.  MACRO-NAME only helps tracing
 # the PRO/EPI pairs.
 m4_define([_m4_defun_epi],
-[m4_divert_pop()dnl
-m4_if(_m4_divert_dump, _m4_divert_diversion,
-      [m4_undivert([GROW])dnl
-m4_undefine([_m4_divert_dump])])dnl
-m4_expansion_stack_pop()dnl
-m4_popdef([_m4_expanding($1)])dnl
-m4_provide([$1])dnl
+[m4_provide([$1])dnl
 ])
 
 
@@ -1313,23 +1302,9 @@ m4_define([m4_before],
 #   `extension' prevents `AC_LANG_COMPILER' from having actual arguments that
 #   it passes to `AC_LANG_COMPILER(C)'.
 m4_define([m4_require],
-[m4_expansion_stack_push(m4_location[: $1 is required by...])dnl
-m4_ifdef([_m4_expanding($1)],
-         [m4_fatal([$0: circular dependency of $1])])dnl
-m4_ifndef([_m4_divert_dump],
-          [m4_fatal([$0: cannot be used outside of an m4_defun'd macro])])dnl
-m4_provide_if([$1],
+[m4_provide_if([$1],
               [],
-              [m4_divert_push(m4_eval(m4_divnum - 1))dnl
-m4_default([$2], [$1])
-m4_divert(m4_defn([_m4_divert_dump]))dnl
-m4_undivert(m4_defn([_m4_divert_diversion]))dnl
-m4_divert_pop(m4_defn([_m4_divert_dump]))])dnl
-m4_provide_if([$1],
-              [],
-              [m4_warn([syntax],
-                       [$1 is m4_require'd but is not m4_defun'd])])dnl
-m4_expansion_stack_pop()dnl
+              [m4_default([$2], [$1])])
 ])