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Diffstat (limited to 'doc/user/file-removal.sgml')
-rw-r--r-- | doc/user/file-removal.sgml | 101 |
1 files changed, 81 insertions, 20 deletions
diff --git a/doc/user/file-removal.sgml b/doc/user/file-removal.sgml index 76a2e01..f64d394 100644 --- a/doc/user/file-removal.sgml +++ b/doc/user/file-removal.sgml @@ -27,7 +27,7 @@ There are two occasions when &SCons; will, by default, remove target files. - The first is when &SCons; determines that + The first is when &SCons; determines that an target file needs to be rebuilt and removes the existing version of the target before executing @@ -44,7 +44,7 @@ <title>Preventing target removal during build: the &Precious; Function</title> <para> - + By default, &SCons; removes targets before building them. Sometimes, however, this is not what you want. For example, you may want to update a library incrementally, @@ -53,23 +53,23 @@ In such cases, you can use the &Precious; method to prevent &SCons; from removing the target before it is built: - + </para> - + <programlisting> env = Environment(RANLIBCOM='') lib = env.Library('foo', ['f1.c', 'f2.c', 'f3.c']) env.Precious(lib) </programlisting> - + <para> - + Although the output doesn't look any different, &SCons; does not, in fact, delete the target library before rebuilding it: - + </para> - + <screen> % <userinput>scons -Q</userinput> cc -o f1.o -c f1.c @@ -77,22 +77,21 @@ cc -o f3.o -c f3.c ar rc libfoo.a f1.o f2.o f3.o </screen> - + <para> - + &SCons; will, however, still delete files marked as &Precious; when the <literal>-c</literal> option is used. - + </para> </section> - <section> <title>Preventing target removal during clean: the &NoClean; Function</title> <para> - + By default, &SCons; removes all built targets when invoked with the <literal>-c</literal> option to clean a source tree of built tragets. @@ -102,25 +101,25 @@ but leave the final targets (the libraries) untouched. - + In such cases, you can use the &NoClean; method to prevent &SCons; from removing a target during a clean: - + </para> - + <programlisting> env = Environment(RANLIBCOM='') lib = env.Library('foo', ['f1.c', 'f2.c', 'f3.c']) env.NoClean(lib) </programlisting> - + <para> - + Notice that the <filename>libfoo.a</filename> is not listed as a removed file: - + </para> - + <screen> % <userinput>scons -Q</userinput> cc -o f1.o -c f1.c @@ -139,3 +138,65 @@ </section> + <section> + <title>Removing additional files during clean: the &Clean; Function</title> + + <para> + + There may be additional files that you want removed + when the <literal>-c</literal> option is used, + but which &SCons; doesn't know about + because they're not normal target files. + For example, perhaps a command you invoke + creates a log file as + part of building the target file you want. + You would like the log file cleaned, + but you don't want to have to teach + SCons that the command + "builds" two files. + + </para> + + <para> + + You can use the &Clean; function to arrange for additional files + to be removed when the <literal>-c</literal> option is used. + Notice, however, that the &Clean; function takes two arguments, + and the <emphasis>second</emphasis> argument + is the name of the additional file you want cleaned + (<filename>foo.log</filename> in this example): + + </para> + + <programlisting> + t = Command('foo.out', 'foo.in', 'build -o $TARGET $SOURCE') + Clean(t, 'foo.log') + </programlisting> + + <para> + + The first argument is the target with which you want + the cleaning of this additional file associated. + In the above example, + we've used the return value from the + &Command; function, + which represents the + <filename>foo.out</filename> + target. + Now whenever the + <filename>foo.out</filename> target is cleaned + by the <literal>-c</literal> option, + the <filename>foo.log</filename> file + will be removed as well: + + </para> + + <screen> + % <userinput>scons -Q</userinput> + build -o foo.out foo.in + % <userinput>scons -Q -c</userinput> + Removed foo.out + Removed foo.log + </screen> + + </section> |