From 72c578fd4b0b4a5a43e18594339ac4ff26c376dc Mon Sep 17 00:00:00 2001 From: Luca Falavigna Date: Sat, 2 Jan 2010 20:56:27 +0100 Subject: Imported Upstream version 1.2.0.d20091224 --- doc/user/parseflags.in | 184 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 184 insertions(+) create mode 100644 doc/user/parseflags.in (limited to 'doc/user/parseflags.in') diff --git a/doc/user/parseflags.in b/doc/user/parseflags.in new file mode 100644 index 0000000..b21df4f --- /dev/null +++ b/doc/user/parseflags.in @@ -0,0 +1,184 @@ + + + + + &SCons; has a bewildering array of construction variables + for different types of options when building programs. + Sometimes you may not know exactly which variable + should be used for a particular option. + + + + + + &SCons; construction environments have a &ParseFlags; method + that takes a set of typical command-line options + and distrbutes them into the appropriate construction variables. + Historically, it was created to support the &ParseConfig; method, + so it focuses on options used by the GNU Compiler Collection (GCC) + for the C and C++ toolchains. + + + + + + &ParseFlags; returns a dictionary containing the options + distributed into their respective construction variables. + Normally, this dictionary would be passed to &MergeFlags; + to merge the options into a &consenv;, + but the dictionary can be edited if desired to provide + additional functionality. + (Note that if the flags are not going to be edited, + calling &MergeFlags; with the options directly + will avoid an additional step.) + + + + + + env = Environment() + d = env.ParseFlags("-I/opt/include -L/opt/lib -lfoo") + l = d.items() + l.sort() + for k,v in l: + if v: + print k, v + env.MergeFlags(d) + env.Program('f1.c') + + + int main() { return 0; } + + + + + scons -Q + + + + + Note that if the options are limited to generic types + like those above, + they will be correctly translated for other platform types: + + + + + scons -Q + + + + + Since the assumption is that the flags are used for the GCC toolchain, + unrecognized flags are placed in &cv-link-CCFLAGS; + so they will be used for both C and C++ compiles: + + + + + + env = Environment() + d = env.ParseFlags("-whatever") + l = d.items() + l.sort() + for k,v in l: + if v: + print k, v + env.MergeFlags(d) + env.Program('f1.c') + + + int main() { return 0; } + + + + + scons -Q + + + + + &ParseFlags; will also accept a (recursive) list of strings as input; + the list is flattened before the strings are processed: + + + + + + env = Environment() + d = env.ParseFlags(["-I/opt/include", ["-L/opt/lib", "-lfoo"]]) + l = d.items() + l.sort() + for k,v in l: + if v: + print k, v + env.MergeFlags(d) + env.Program('f1.c') + + + int main() { return 0; } + + + + + scons -Q + + + + + If a string begins with a "!" (an exclamation mark, often called a bang), + the string is passed to the shell for execution. + The output of the command is then parsed: + + + + + + env = Environment() + d = env.ParseFlags(["!echo -I/opt/include", "!echo -L/opt/lib", "-lfoo"]) + l = d.items() + l.sort() + for k,v in l: + if v: + print k, v + env.MergeFlags(d) + env.Program('f1.c') + + + int main() { return 0; } + + + + + scons -Q + + + + + &ParseFlags; is regularly updated for new options; + consult the man page for details about those currently recognized. + + -- cgit v1.2.3