Make largely insulates you
from changes in build platform, and ant does so almost completely; a batch ?¬?le
or shell script will however only run on a Microsoft or Unix OS, respectively, and
will quite probably be dependent on a particular version of that OS. If you ?¬?nd
yourself having to write command scripts on several platforms a good resource is
www.ss64.com, which documents the commands for Windows, Linux, and Mac
OS X.
One main bene?¬?t of make is often lost when moving from writing source ?¬?les by
hand to generating them. Make is able to see which ?¬?les have changed since the
application was last built, and only update those intermediate ?¬?les that are dependent
on the changed ?¬?les. Generators normally regenerate all ?¬?les, since they cannot tell
which models have changed (in particular where the same object is reused in multiple
models). This means all ?¬?les look new to make, and all will be compiled, sometimes
taking much longer than would strictly be necessary.Avoiding this problem is simple,
and the better DSM tools already support it automatically: if a generated ?¬?le is
identical to the ?¬?le of the same name already on disk, leave that ?¬?le untouched. If
your DSM tool does not support this, it is possible to create the same effect by
generating source ?¬?le contents with a temporary extension, comparing them to the
previous source ?¬?le, and only copying them over the previous version if there is a
difference.
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