[CMake] configure_file as a build step?

[Jensen, Erik A]

That worked, although a little roundabout. Thank you.

Would there be any interest in having an easier way to do this? It seems like it could be usefully in a fair number of situations.

Maybe an additional -E command:
cmake -E configure_file -D var1=value1 -D var2=value2 --at-only infile outfile

Or even a way to run arbitrary CMake commands without a script file:
cmake -D var1=value1 -D var2=value2 -R "configure_file(infile outfile @ONLY)"

This would make it possible to avoid having a whole other file just to execute one CMake command at build time.

Thoughts?

-----Original Message-----
From: cmake-bounces at cmake.org [mailto:cmake-bounces at cmake.org] On Behalf Of Michael Wild
Sent: Tuesday, May 01, 2012 10:33 PM
To: cmake at cmake.org
Subject: Re: [CMake] configure_file as a build step?

You can configure_file() a CMake-script which itself then performs the
configure_file() in a custom command. E.g.:


# CMakeLists.txt:
#...
set(FOO "Some text to show up in json_file.json")
set(BAR "More text")
configure_file(configure_json_file.cmake.in
  ${CMAKE_CURRENT_BINARY_DIR}/configure_json_file.cmake @ONLY)

add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/json_file.json
  COMMAND ${CMAKE_COMMAND} -P
    ${CMAKE_CURRENT_BINARY_DIR}/configure_json_file.cmake
  DEPENDS
    ${CMAKE_CURRENT_BINARY_DIR}/configure_json_file.cmake
    ${CMAKE_CURRENT_SOURCE_DIR}/json_file.json.in
  COMMENT "Configuring json_file.json"
  VERBATIM)

add_custom_target(configure_json ALL
  DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/json_file.json)
#...
# EOF


# configure_json_file.cmake.in:
set(SRC_DIR "@CMAKE_CURRENT_SOURCE_DIR@")
set(BIN_DIR "@CMAKE_CURRENT_BINARY_DIR@")
set(FOO "@FOO@")
set(BAR "@BAR@")
configure_file(${SRC_DIR}/json_file.json.in
  ${BIN_DIR}/json_file.json @ONLY)
# EOF


HTH

Michael

On 05/02/2012 01:16 AM, Jensen, Erik A wrote:
> I have a JSON file that needs to have some values set based on the
> project's configuration. During development, this file can change rather
> frequently.
> 
>  
> 
> Currently, I am using configure_file to fill in the required values.
> Unfortunately, every time the file is modified, it triggers CMake to do
> a complete configuration and generation step. This slows down rebuilds,
> and is especially problematic when using Visual Studio, where the
> solution has to be reloaded after it is regenerated.
> 
>  
> 
> Is there any way to have the file generated as part of the build instead
> of part of the configuration/generation step?
> 
>  
> 
> Thanks,
> 
> -- Erik