[CMake] Technique for generating projects that depend on generated sources

[Michael Jackson]

I believe you can have cmake read the contents of a file into a  
variable. If the file that lists the generated files is a semi-colon  
or space delimited (assuming no spaces in the names or paths) then you  
can read the file directly into a cmake variable, then use that  
variable as the source list to add_executable or add_library.

file(STRINGS filename variable [LIMIT_COUNT num]
[LIMIT_INPUT numBytes] [LIMIT_OUTPUT numBytes]
[LENGTH_MINIMUM numBytes] [LENGTH_MAXIMUM numBytes]
[NEWLINE_CONSUME] [REGEX regex]
[NO_HEX_CONVERSION])


STRINGS will parse a list of ASCII strings from a file and store it in  
a variable. Binary data in the file are ignored. Carriage return (CR)  
characters are ignored. It works also for Intel Hex and Motorola S- 
record files, which are automatically converted to binary format when  
reading them. Disable this using NO_HEX_CONVERSION.


file(READ filename variable [LIMIT numBytes] [OFFSET offset] [HEX])

READ will read the content of a file and store it into the variable.  
It will start at the given offset and read up to numBytes. If the  
argument HEX is given, the binary data will be converted to  
hexadecimal representation and this will be stored in the variable.

I may have an example in my hdf5 cmake build that does close to what  
you want.


_________________________________________________________
Mike Jackson                  mike.jackson at bluequartz.net
BlueQuartz Software                    www.bluequartz.net
Principal Software Engineer                  Dayton, Ohio



On Feb 27, 2009, at 8:01 AM, Steve Huston wrote:

> Thanks for the advice, Bill.
>
> My situation is somewhat different, though. The output source files
> are not known ahead of time. Thus, the general scheme is:
>
> - build runs the source generator; one of the outputs is a file
> containing the names of the generated sources.
> - rerun cmake to regenerate the build now that the complete list of
> sources is known.
> - rerun the build with the complete set of sources
>
> I tried to make that all happen automatically in the build.
>
> -Steve
>
> --
> Steve Huston, Riverace Corporation
> Check out my networked programming blog at
> http://stevehuston.wordpress.com/
>
>
>> -----Original Message-----
>> From: Bill Hoffman [mailto:bill.hoffman at kitware.com]
>> Sent: Thursday, February 26, 2009 9:04 PM
>> To: Steve Huston
>> Cc: cmake at cmake.org
>> Subject: Re: [CMake] Technique for generating projects that
>> depend on generated sources
>>
>>
>> Steve Huston wrote:
>>> I'm working on a project that involves generating a large
>> chunk of the
>>> sources from separate definitions. The set of generated source
> files
>>> is not known before it is generated.
>>>
>>> The approach I've tried so far (and I'm very new to cmake) is to
>>> define a custom_command that does the source generation, then run
>>> cmake over again to regenerate the project files.
>>>
>>> I tried this out with Microsoft Visual Studio... When I
>> tried a build
>>> from inside Visual Studio the command to generate the
>> sources happened
>>> like I want, but when it tried to re-run cmake to regenerate the
>>> project with the now-known set of generated sources, an error was
>>> thrown because cmake couldn't update VS macros while VS is
> running.
>>>
>>> So close, yet so far... ;-)
>>>
>>> Is there a common pattern for how to address this type of
> situation?
>>>
>>
>> Look at the FAQ:
>>
>> http://www.cmake.org/Wiki/CMake_FAQ#How_do_I_generate_an_execu
> table.2C_then_use_the_executable_to_generate_a_file.3F
>
> -Bill
>
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