[CMake] Parallel builds do not work correctly when using "cmake -E copy" to copy files

Bill Hoffman bill.hoffman at kitware.com
Wed Feb 6 22:37:21 EST 2008


Alan W. Irwin wrote:

> 
> My first interpretation was "that" referred to graphviz, but in fact the
> file was produced at cmake time, and it was a simple matter to process 
> it by
> hand using the "dot" command-line tool (even though I had never heard of
> that tool or graphviz before). "gv" has errors for both the ps and pdf
> results, but I think that is because the latest gv is extra careful about
> non-standard ps and pdf files.  xpdf could understand the pdf output, but I
> have to say the result is black with dependency lines to a frightening
> extent. I can send the pdf file to Brad and/or you off-list if either of 
> you
> is interested in being frightened by the PLplot dependencies as well.  :-)
> 
> Seriously, I am fairly impressed with the graphviz result, and adding in
> the file depends would add a lot of value to the result.
> 
> If your "that" refers to file depends instead of graphviz, I don't
> understand your comment since surely file depend information is 
> available at
> cmake time?
> 

No file level depends are done mostly a build time.  This is a 
performance issue.  Some generators like VS IDE do file level depends by 
themselves.  With the makefiles cmake computes the depends, but at build 
time not cmake time.  The custom command stuff output input is known at 
cmake time, and maybe enough for what you want.  But if you have a file 
foo.c with #include <foo.h>, cmake does not know that foo.c depends on 
foo.h until build time.

-Bill


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