On 2013-05-29 03:32, Michael Wild wrote:
On 28.05.2013 22:07, Matthew Woehlke wrote:
Is there a built-in way to write a string to a file (a la FILE(WRITE))
that will only write the file if the content would be different? (Or
does FILE(WRITE) already work this way despite no obvious hint in the
documentation that it does?)
Right now I am writing to a temporary file and running cmake -E
copy_if_different, then removing the temporary file, but this seems
inelegant and I am wondering if there is a better solution.
AFAIK the file is written unconditionally, but you can then use
configure_file(... COPYONLY) instead of a round-about execute_process()
that calls cmake -E copy_if_different.
Actually... no. Well, I could (it would technically work), but because I
always write the file, it causes the build rules to always be out of
date (i.e. CMake is re-run every time), which is decidedly sub-optimal :-).
(Didn't realize that until I finally decided to try it, just now.
Although I wonder now if I had actually tried configure_file originally
and switched to execute_process for exactly this reason...)
So... stronger argument for maybe adding this as an enhancement to CMake.
--
Matthew
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