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all or A part of a large system: SCons will likely take some further time to "think about" what must be created before it issues the first build command (or decides that everything is as much as date and nothing need to be rebuilt). In practice, having SCons scan files saves time relative to your amount of prospective time lost to tracking down subtle problems introduced by incorrect dependencies.
Being a performance enhancement, SCons provides a means to make use of a file's content signature, but to read those contents only when the file's timestamp has changed. To try and do this, call the Decider function with 'content-timestamp' argument as follows:
The environment is not a simple variable. It truly is an object with various methods or subroutines of its very own. The methods and subroutines allow the creation of programs whether they are in Java, C++, or C.
Unknown variables: NOT_KNOWN Of course, you can process the items during the dictionary returned because of the UnknownVariables function in any way ideal to your build configuration, including just printing a warning message although not exiting, logging an error somewhere, etc.
scons: `.' is approximately date. A construction environment is actually an object with associated methods and attributes.
than a focus on file, the goal file will not be rebuilt. This can happen if an old copy of a source file is restored from a backup archive, for instance. The contents of your restored file will likely be different than they were being the last time a dependent focus on was designed, although the goal will not be rebuilt because the modification time of your source file is just not newer than the focus on.
SCons provides a COMMAND_LINE_TARGETS variable that lets you fetch the list of targets that ended up specified about the command line. You can utilize the targets to control the build in almost any way you would like.
env = Environment() By default, SCons initializes every new construction environment with a set of construction variables based about the applications that it finds on your system, plus the default list of builder methods necessary for using those equipment.
If you need to employ a file from another directory, It is really sometimes more easy to specify the path to your file in another directory from the highest-level SConstruct directory, even when you happen to be using that file in the subsidiary SConscript file in a very subdirectory.
This guideline intends to coach you how to employ SCons effectively and efficiently, by providing a range of illustrations and usage scenarios. As such It isn't exactly a tutorial (as generally those build a single case in point matter from start to finish), but if you are just starting with SCons it
When you need to create a directory, use the Mkdir manufacturing unit. By way of example, if we need to process a file in a temporary directory in which the processing Resource will create other files that we don't treatment about, you could use:
One of many critical great things about SCons is its cross-platform abilities, so most of what goes on here will work on Windows even if it had been tested over a Linux system.
, created within the Python programming language. This is in distinction to most alternative build instruments, which typically invent a completely new language to configure the build. SCons still has a learning curve, of course, because you have to know what functions to call to set up your build properly, but the underlying syntax used should be familiar to anyone who has ever looked in a Python script. Paradoxically, using Python as being the configuration file format makes SCons
keyword argument to AddOption is specified, the value is the variable name. given. If not given, it is the name (without the leading hyphens) in the first long option name given to AddOption after replacing any remaining hyphen characters with underscores, due to the fact hyphens will not be lawful in Python identifier names. SetOption works for options added with AddOption, but only if they were created with settable=True