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Diffstat (limited to 'doc/man/scons.1')
| -rw-r--r-- | doc/man/scons.1 | 42 |
1 files changed, 40 insertions, 2 deletions
diff --git a/doc/man/scons.1 b/doc/man/scons.1 index 1332020..8df46cf 100644 --- a/doc/man/scons.1 +++ b/doc/man/scons.1 @@ -98,7 +98,7 @@ so you may use normal Python scripting capabilities (such as flow control, data manipulation, and imported Python libraries) to handle complicated build situations. .BR scons , -however, reads all of the SConscript files +however, reads and executes all of the SConscript files .I before it begins building any targets. To make this obvious, @@ -122,6 +122,34 @@ may be suppressed using the option. .B scons +does not automatically propagate +the external environment used to execute +.B scons +to the commands used to build target files. +This is so that builds will be guaranteed +repeatable regardless of the environment +variables set at the time +.B scons +is invoked. +This also means that if the compiler or other commands +that you want to use to build your target files +are not in standard system locations, +.B scons +will not find them unless +you explicitly set the PATH +to include those locations. +Whenever you create an +.B scons +construction environment, +you can propagate the value of PATH +from your external environment as follows: + +.ES +import os +env = Environment(ENV = {'PATH' : os.environ['PATH']}) +.EE + +.B scons can scan known input files automatically for dependency information (for example, #include statements in C or C++ files) and will rebuild dependent files appropriately @@ -1939,7 +1967,17 @@ USERNAME. .RI AlwaysBuild( target ", ...)" Marks each given .I target -so that it will always be rebuilt. +so that it is always assumed to be out of date, +and will always be rebuilt if needed. +Note, however, that +.BR AlwaysBuild () +does not add its target(s) to the default target list, +so the targets will only be built +if they are specified on the command line, +or are a dependent of a target specified on the command line--but +they will +.I always +be built if so specified. Multiple targets can be passed in to a single call to .BR AlwaysBuild (). |