Merged revisions 3057-3059,3061-3264 via svnmerge from

http://scons.tigris.org/svn/scons/branches/core

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  r3061 | stevenknight | 2008-06-10 10:06:24 -0700 (Tue, 10 Jun 2008) | 3 lines

  Issue 2085:  Fix man page indentation under Debian systems.
  Also add escape characters to the beginnings of some necessary lines.
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  r3063 | GregNoel | 2008-06-10 17:50:28 -0700 (Tue, 10 Jun 2008) | 1 line

  Add David as a member; parametize input file
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  r3064 | stevenknight | 2008-06-11 07:22:23 -0700 (Wed, 11 Jun 2008) | 3 lines

  Issue 1973:  Clarify the man page description of the SConscript(src_dir)
  argument.
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  r3065 | stevenknight | 2008-06-11 11:25:00 -0700 (Wed, 11 Jun 2008) | 3 lines

  Issues 1974, 1999:  document {Add,Get,Set}Option().  Reorganize the
  section a little bit, other minor edits.
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  r3066 | garyo | 2008-06-12 19:53:51 -0700 (Thu, 12 Jun 2008) | 1 line

  Document GetBuildFailures in Users Guide.  Closes issue #1989.
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  r3067 | stevenknight | 2008-06-14 06:42:07 -0700 (Sat, 14 Jun 2008) | 2 lines

  Fix build errors from undefined &GetBuildFailures; entity in doc.
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  r3073 | garyo | 2008-06-14 18:40:20 -0700 (Sat, 14 Jun 2008) | 1 line

  Fix issue #1538 (Handling of string argument in Action.Action).  Includes test.
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  r3074 | garyo | 2008-06-14 19:11:30 -0700 (Sat, 14 Jun 2008) | 1 line

  doc: Trivial man page typo fix.
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  r3075 | stevenknight | 2008-06-15 14:35:13 -0700 (Sun, 15 Jun 2008) | 3 lines

  Add a test to make sure the env.RCS() applied to an individual file works
  correctly when the checked-out copy is changed.
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  r3076 | stevenknight | 2008-06-15 23:07:17 -0700 (Sun, 15 Jun 2008) | 2 lines

  Issue 2025:  User's Guide updates from Randall Spangler's review.
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  r3078 | stevenknight | 2008-06-16 06:26:13 -0700 (Mon, 16 Jun 2008) | 2 lines

  Issue 1990:  Document the Requires() function in the Users's Guide.
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  r3082 | stevenknight | 2008-06-16 19:31:00 -0700 (Mon, 16 Jun 2008) | 3 lines

  Fix the second example in the AddMethod() chapter.  Show the Windows
  output generating a resource file.  Other copyedits.
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  r3083 | stevenknight | 2008-06-17 06:44:02 -0700 (Tue, 17 Jun 2008) | 2 lines

  Fix misspelled entity:  &Builders; => &Builder;s.
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  r3084 | stevenknight | 2008-06-17 08:30:13 -0700 (Tue, 17 Jun 2008) | 3 lines

  Issue 1588:  - Document suggested use of the Viual C/C++ /FC option to fix
  the ability to double-click on file names in compilation error messages.
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  r3085 | stevenknight | 2008-06-17 08:50:33 -0700 (Tue, 17 Jun 2008) | 3 lines

  Issue 1687:  Document the need to use Clean() for any SideEffect()
  files that must be explicitly removed when their targets are removed.
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  r3086 | stevenknight | 2008-06-17 10:59:28 -0700 (Tue, 17 Jun 2008) | 2 lines

  Typo fix in the new SideEffect() paragraph.  (Gary Oberbrunner)
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  r3088 | cournape | 2008-06-17 19:55:27 -0700 (Tue, 17 Jun 2008) | 3 lines

  Initialized merge tracking via "svnmerge" with revisions "1-3087" from
  http://scons.tigris.org/svn/scons/branches/vs_revamp
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  r3094 | stevenknight | 2008-06-19 09:52:16 -0700 (Thu, 19 Jun 2008) | 3 lines

  Change the User's Guide to use the new Variables object and its
  associated function for controlling command-line build variables.
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  r3115 | stevenknight | 2008-06-25 06:46:36 -0700 (Wed, 25 Jun 2008) | 2 lines

  Issue 2072:  end indentation after generated Builder text.
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  r3116 | stevenknight | 2008-06-25 19:07:15 -0700 (Wed, 25 Jun 2008) | 2 lines

  Reorganize the command-line arguments chapter.
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  r3117 | stevenknight | 2008-06-25 19:13:58 -0700 (Wed, 25 Jun 2008) | 2 lines

  Editing pass for formatting in the Glob() sections.
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  r3118 | stevenknight | 2008-06-25 19:23:09 -0700 (Wed, 25 Jun 2008) | 3 lines

  Wording changing:  Preventing => Controlling, because the chapter
  also talks about how to clean additional targets.
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  r3119 | stevenknight | 2008-06-25 19:50:41 -0700 (Wed, 25 Jun 2008) | 2 lines

  Fix missing </literal> tags, minor wording fix.
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  r3120 | stevenknight | 2008-06-25 19:58:34 -0700 (Wed, 25 Jun 2008) | 2 lines

  Add "the Default Function" to the appropriate subsection title.
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  r3121 | stevenknight | 2008-06-26 08:33:43 -0700 (Thu, 26 Jun 2008) | 2 lines

  Issue 1988:  Document the Variables.UnknownVariables() method.
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  r3122 | stevenknight | 2008-06-26 08:35:51 -0700 (Thu, 26 Jun 2008) | 3 lines

  Remove comments listing some of the variables that have been
  documented recently.
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  r3123 | stevenknight | 2008-06-26 12:42:53 -0700 (Thu, 26 Jun 2008) | 2 lines

  Issue 2118:  Fix incorrectly swapped man page text.  (Alexey Zezukin)
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  r3124 | bdbaddog | 2008-06-26 21:23:46 -0700 (Thu, 26 Jun 2008) | 2 lines

  Fix bug 2108 - duplicate text in description of interactive mode
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  r3125 | stevenknight | 2008-06-27 21:54:56 -0700 (Fri, 27 Jun 2008) | 3 lines

  Issue 1993:  Document the $*COMSTR variables, the Progress() function,
  and create a common "Controlling Build Output" chapter.
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  r3126 | garyo | 2008-06-28 05:46:44 -0700 (Sat, 28 Jun 2008) | 1 line

  Fix issue 2105; temporarily omit doc saying that SetOption can override user-created Options (until that is implemented).
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  r3127 | stevenknight | 2008-06-28 07:29:18 -0700 (Sat, 28 Jun 2008) | 2 lines

  Issue 1747:  Explicitly document use of Node lists as input to Depends().
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  r3128 | stevenknight | 2008-06-28 07:48:32 -0700 (Sat, 28 Jun 2008) | 6 lines

  White space change:  indent the construction environment sections
  further to make way for combining this chapter with others to make
  one big "Controlling Environments" chapter.
  Also, get rid of some now-unnecessary doc from the old Cons classic
  POD, that was taking up space here waiting to be documented.
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  r3129 | cournape | 2008-06-29 01:56:30 -0700 (Sun, 29 Jun 2008) | 3 lines

  Initialized merge tracking via "svnmerge" with revisions "1-3128" from
  http://scons.tigris.org/svn/scons/branches/trygrep
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  r3143 | stevenknight | 2008-07-02 10:29:39 -0700 (Wed, 02 Jul 2008) | 3 lines

  Initialized merge tracking via "svnmerge" with revisions "1-3142" from
  http://scons.tigris.org/svn/scons/branches/sgk_lookup
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  r3181 | stevenknight | 2008-07-08 07:17:27 -0700 (Tue, 08 Jul 2008) | 4 lines

  Reorganize the discussion of different environments into one chapter.
  Document the SetDefault(), PrependUnique(), AppendUnique(),
  PrependENVPath() and AppendENVPath() functions.
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  r3182 | stevenknight | 2008-07-08 08:47:55 -0700 (Tue, 08 Jul 2008) | 2 lines

  Issue 1998:  Docment the ARGLIST variable in the User's Guide.
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  r3194 | GregNoel | 2008-07-09 23:16:51 -0700 (Wed, 09 Jul 2008) | 1 line

  remove unnecessary trailing spaces on lines
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  r3204 | stevenknight | 2008-07-11 08:29:18 -0700 (Fri, 11 Jul 2008) | 2 lines

  Issue 1853:  Remove referenc to SCons.Util.CLVar from a doc example.
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  r3206 | GregNoel | 2008-07-12 02:08:19 -0700 (Sat, 12 Jul 2008) | 1 line

  Another go at describing VariantDir()
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  r3213 | stevenknight | 2008-07-13 08:57:57 -0700 (Sun, 13 Jul 2008) | 3 lines

  Set /branches/comments in svnmerge-integrated property to allow
  merging changes in both directions.
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  r3217 | stevenknight | 2008-07-16 06:52:44 -0700 (Wed, 16 Jul 2008) | 2 lines

  Update the copyright year in the User's Guide.
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  r3218 | stevenknight | 2008-07-16 07:08:52 -0700 (Wed, 16 Jul 2008) | 3 lines

  Issue 1881:  Add man page text clarifying the behavior of
  Add{Pre,Post}Action() when multiple targets are specified.
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  r3223 | stevenknight | 2008-07-18 08:18:45 -0700 (Fri, 18 Jul 2008) | 3 lines

  Initialized merge tracking via "svnmerge" with revisions "1-3222" from
  http://scons.tigris.org/svn/scons/branches/sgk_subst
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  r3231 | stevenknight | 2008-07-22 01:58:11 -0700 (Tue, 22 Jul 2008) | 4 lines

  Enhance MSVSProject() tests so they're runnable on any system, regardless
  of whether Visual Studio is installed, or if it's even a Windows system
  at all.
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  r3237 | GregNoel | 2008-07-26 00:07:49 -0700 (Sat, 26 Jul 2008) | 1 line

  Issue 1983: Document ParseConfig, MergeFlags, and ParseFlags for the Users' Guide
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  r3238 | stevenknight | 2008-07-26 08:38:18 -0700 (Sat, 26 Jul 2008) | 3 lines

  Follow-ons for building the User's Guide with Greg's recent additions
  for MergeFlags() and ParseFlags().
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  r3239 | stevenknight | 2008-07-26 09:52:40 -0700 (Sat, 26 Jul 2008) | 3 lines

  Re-arrange some sections talking about creating construction environments
  and fetching/expanding variables.
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  r3240 | stevenknight | 2008-07-26 12:16:11 -0700 (Sat, 26 Jul 2008) | 2 lines

  Stylistic editing of new {Merge,Parse}{Config,Flags} sections.
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  r3241 | GregNoel | 2008-07-26 12:42:42 -0700 (Sat, 26 Jul 2008) | 1 line

  Issue 1987: Document SideEffect for Users' Guide (incomplete)
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  r3242 | stevenknight | 2008-07-26 13:27:56 -0700 (Sat, 26 Jul 2008) | 2 lines

  Correct dumb XML mistakes in my last checkin.
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  r3243 | stevenknight | 2008-07-26 13:34:05 -0700 (Sat, 26 Jul 2008) | 2 lines

  One-character typo.  Gah.
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  r3244 | stevenknight | 2008-07-26 13:44:14 -0700 (Sat, 26 Jul 2008) | 2 lines

  Issue 1977,1980:  document the Exit() and Flatten() functions.
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  r3245 | stevenknight | 2008-07-27 10:24:12 -0700 (Sun, 27 Jul 2008) | 14 lines

  Updates to the new SideEffect section (kudos to Greg).

  While working on this, Greg discovered a bug (issue #2154) that prevents
  a SideEffect() file from being used as input to another builder call; it
  makes the builder target not get build when run in paralle (e.g. -j2)...
  :-(  So this patch comments out that section of Greg's section.

  This also contains my usual editing pass.  In this case I changed some
  of the examples and added a bunch of text to try to help clarify some
  things that seemed important.  I also added a closing paragraph warning
  that SideEffect() really shouldn't be used as an alternative to specifying
  multiple target files in a Builder call when a command builds more than
  one file that you care about.
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  r3246 | stevenknight | 2008-07-27 10:31:17 -0700 (Sun, 27 Jul 2008) | 2 lines

  Proofreading edits of the MergeFlags() section.  (Greg Noel)
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  r3247 | stevenknight | 2008-07-27 11:17:27 -0700 (Sun, 27 Jul 2008) | 2 lines

  Issue 1976:  document ensure{Python,SCons}Version() in the User's Guide.
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  r3249 | GregNoel | 2008-07-28 15:57:00 -0700 (Mon, 28 Jul 2008) | 1 line

  Add svn-bisect script
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1 files changed, 216 insertions, 0 deletions

diff --git a/doc/user/sideeffect.in b/doc/user/sideeffect.in
new file mode 100644
index 0000000..cbeefae
--- /dev/null
+++ b/doc/user/sideeffect.in
@@ -0,0 +1,216 @@
+<!--
+
+  __COPYRIGHT__
+
+  Permission is hereby granted, free of charge, to any person obtaining
+  a copy of this software and associated documentation files (the
+  "Software"), to deal in the Software without restriction, including
+  without limitation the rights to use, copy, modify, merge, publish,
+  distribute, sublicense, and/or sell copies of the Software, and to
+  permit persons to whom the Software is furnished to do so, subject to
+  the following conditions:
+
+  The above copyright notice and this permission notice shall be included
+  in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+  KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+  WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+-->
+
+ <!--
+
+ <para>
+
+ If &SCons; is unaware that a build step produces an extra file,
+ the &SideEffect; method can be used to identify it,
+ so that the file can be used as a dependency in subsequent build steps.
+ However, the primary use for the &SideEffect; method
+ is to prevent two build steps from simultaneously modifying the same file.
+
+ </para>
+
+ TODO: currently doesn't work due to issue #2154:
+ http://scons.tigris.org/issues/show_bug.cgi?id=2154
+
+ <para>
+
+ If more than one build step creates or manipulates the same file,
+ it can cause unpleasant results if both build steps are run at the same time.
+ The shared file is declared as a side-effect of building the primary targets
+ and &SCons; will prevent the two build steps from running in parallel.
+
+ </para>
+
+ <para>
+
+ In this example, the <filename>SConscript</filename> uses
+ &SideEffect; to inform &SCons; about the additional output file.
+
+ </para>
+
+ <scons_example name="SideEffectSimple">
+   <file name="SConstruct" printme="1">
+    env = Environment()
+    f2 = env.Command('file2', 'log', Copy('$TARGET', '$SOURCE'))
+    f1 = env.Command('file1', [],
+        'echo >$TARGET data1; echo >log updated file1'))
+    env.SideEffect('log', env.Command('file1', [],
+        'echo >$TARGET data1; echo >log updated file1'))
+   </file>
+ </scons_example>
+
+ <para>
+
+ Even when run in parallel mode, &SCons; will run the two steps in order:
+
+ </para>
+
+ <scons_output example="SideEffectSimple">
+    <scons_output_command>scons -Q --jobs=2</scons_output_command>
+ </scons_output>
+
+ -->
+
+ <para>
+
+ Sometimes a program the you need to call
+ to build a target file
+ will also update another file,
+ such as a log file describing what the program
+ does while building the target.
+ For example, we the folowing configuration
+ would have &SCons; invoke a hypothetical
+ script named <application>build</application>
+ (in the local directory)
+ with command-line arguments that write
+ log information to a common
+ <filename>logfile.txt</filename> file:
+
+ </para>
+
+ <screen>
+ env = Environment()
+ env.Command('file1.out', 'file.in',
+             './build --log logfile.txt $SOURCE $TARGET')
+ env.Command('file2.out', 'file.in',
+             './build --log logfile.txt $SOURCE $TARGET')
+ <screen>
+
+ <para>
+
+ This can cause problems when running
+ the build in parallel if
+ &SCons; decides to update both targets
+ by running both program invocations at the same time.
+ The multiple program invocations
+ may interfere with each other
+ writing to the common log file,
+ leading at best to intermixed output in the log file,
+ and at worst to an actual failed build
+ (on a system like Windows, for example,
+ where only one process at a time can open the log file for writing).
+
+ </para>
+
+ <para>
+
+ We can make sure that &SCons; does not
+ run these <application>build</application>
+ commands at the same time
+ by using the &SideEffect; function
+ to specify that updating
+ the <filename>logfile.txt</filename> file
+ is a side effect of building the specified
+ <filename>file1</filename>
+ and
+ <filename>file2</filename>
+ target files:
+
+ </para>
+
+ <scons_example name="SideEffectShared">
+   <file name="SConstruct" printme="1">
+   env = Environment()
+   f1 = env.Command('file1.out', 'file1.in',
+                    './build --log logfile.txt $SOURCE $TARGET')
+   f2 = env.Command('file2.out', 'file2.in',
+                    './build --log logfile.txt $SOURCE $TARGET')
+   env.SideEffect('logfile.txt', f1 + f2)
+   </file>
+   <file name="file1.in">file1.in</file>
+   <file name="file2.in">file2.in</file>
+   <file name="build" chmod="0755">
+   cat
+   </file>
+ </scons_example>
+
+ <para>
+
+ </para>
+
+ <para>
+
+ This makes sure the the two
+ <application>./build</application> steps are run sequentially,
+ even withthe <filename>--jobs=2</filename> in the command line:
+
+ </para>
+
+ <scons_output example="SideEffectShared">
+    <scons_output_command>scons -Q --jobs=2</scons_output_command>
+ </scons_output>
+
+ <para>
+
+ The &SideEffect; function can be called multiple
+ times for the same side-effect file.
+ Additionally, the name used as a &SideEffect; does not
+ even need to actually exist as a file on disk.
+ &SCons; will still make sure
+ that the relevant targets
+ will be executed sequentially, not in parallel:
+
+ </para>
+
+ <scons_example name="SideEffectParallel">
+   <file name="SConstruct" printme="1">
+    env = Environment()
+    f1 = env.Command('file1.out', [], 'echo >$TARGET data1')
+    env.SideEffect('not_really_updated', f1)
+    f2 = env.Command('file2.out', [], 'echo >$TARGET data2')
+    env.SideEffect('not_really_updated', f2)
+   </file>
+ </scons_example>
+
+ <scons_output example="SideEffectParallel">
+    <scons_output_command>scons -Q --jobs=2</scons_output_command>
+ </scons_output>
+
+ <para>
+
+ Note that it might be tempting to
+ use &SideEffect; for additional target files
+ that a command produces.
+ For example, versions the Microsoft Visual C/C++ compiler
+ produce a <filename>foo.ilk</filename>
+ alongside compiling <filename>foo.obj</filename> file.
+ Specifying <filename>foo.ilk</filename> as a
+ side-effect of <filename>foo.obj</filename>
+ is <emphasis>not</emphasis> a recommended use of &SideEffect;,
+ because &SCons; handle side-effect files
+ slightly differently in its analysis of the dependency graph.
+ When a command produces multiple output files,
+ they should be specified as multiple targets of
+ the call to the relevant builder function,
+ and the &SideEffect; function itself should really only be used
+ when it's important to ensure that commands are not executed in parallel,
+ such as when a "peripheral" file (such as a log file)
+ may actually updated by more than one command invocation.
+
+ </para>