[CMake] Is it possible to obtain the exact cmake command line used to invoke cmake from within cmake?

[Alan W. Irwin]

On 2007-10-28 20:55+0100 Alexander Neundorf wrote:

> On Sunday 28 October 2007, Eric Noulard wrote:
>> 2007/10/27, Alan W. Irwin <irwin at beluga.phys.uvic.ca>:
>>> As I respond to issues with the PLplot CMake-based build system that are
>>> reported by our users, I repeatedly find myself asking them to report the
>>> exact cmake command line that they used as well as full output from the
>>> cmake command.  If from within cmake we could print out a string
>>> corresponding to the exact cmake command line, then that simplifies my
>>> request to them for a full bug report.
>>>
>>> Is it possible to obtain the exact command line used to invoke cmake
>>> from within cmake?
>>
>> I don't know if it's already possible or not but I would be very interested
>> in the feature too. Helping user to use the build system is of
>> great interest.
>>
>> I think I would be useful to have the exact CMake command line
>>
>> 1) as a comment inside CMakeCache.txt
>> 2) as a CMake string var something like:
>>     CMAKE_COMMAND_LINE
>>
>> Note that may be  CMAKE_COMMAND_LINE should indicate
>> what CMake tool was used: cmake, CMakeSetup, ccmake etc...
>>
>> Should on of us file a feature request?
>
> Not sure how much this would help.
>
> If you use ccmake, you don't need to specify arguments at all. You can later
> on run cmake or ccmake again and change variables (using ccmake or -D),
> actually several runs may be required.
>
> So the initial command line doesn't have to contain everything you might want
> to know. I guess looking at the cache makes more sense.

I agree ccmake is a more complex case since the user could use the CLI to
fiddle with the options that were specified on the command line.  Also, our
users could further obfuscate bugs by hand-editing the cache file. To avoid
that ambiguity we ask for bug reports from cmake executed in an initially
empty directory.  For that case the feature request makes sense (and would
also make sense for ccmake if we asked users not to fiddle with the options
using the ccmake CLI when reporting bugs).

I could also justify this feature at a philosophical level, a language such
as C gives the user access to exactly what was specified on the command line
(even though there are general ways to communicate with the C programme
other than the command line).  Shouldn't cmake and ccmake do the same?

If the CMake developers don't think this is worth the trouble, that is fine.
I can always fall back to asking our users to send in the cache file with
their bug report.  (Thanks for that reminder, Alex.) However, that file is
quite lengthy and filled with excess information compared to the nice
summary you get from a single string containing the cmake (or ccmake when
the options aren't fiddled with using that CLI) command line.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
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