[CMake] Why is this custom command run twice?

[Aaron_Wright at selinc.com]

Thanks for checking on this Brad.

-------------------------------------------------------------
Aaron Wright




From:
Brad King <brad.king at kitware.com>
To:
Aaron_Wright at selinc.com
Cc:
cmake at cmake.org, Michael Wild <themiwi at gmail.com>
Date:
04/23/2010 11:59 AM
Subject:
Re: [CMake] Why is this custom command run twice?
Sent by:
cmake-bounces at cmake.org



Aaron_Wright at selinc.com wrote:
> This builds ok the first time, but then change the "generated.txt.in"
> and run the build twice and the second time you'll see "Using
> generated.txt" again, which I don't want to see. I've tried VS 2008 and
> NMake, using CMake 2.8 and 2.8.1.

I was able to reproduce this.  There is nothing wrong with the project
that CMake generates in VS.  The problem seems to be with the windows
filesystem timestamp granularity.  The code below changes the touch
into a copy, and the problem goes away.

The code can actually be simpler, too.  CMake 2.8 (and 2.6 I think)
automatically handles relative output files with respect to the
build tree.

-Brad


CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
PROJECT(quick_test)

ADD_CUSTOM_COMMAND(
  OUTPUT generated.txt
  COMMAND ${CMAKE_COMMAND} -E copy
   ${PROJECT_SOURCE_DIR}/generated.txt.in
   ${PROJECT_BINARY_DIR}/generated.txt
  DEPENDS generated.txt.in
  )

ADD_CUSTOM_COMMAND(
  OUTPUT generated_used.stamp
  COMMAND ${CMAKE_COMMAND} -E copy
   ${PROJECT_BINARY_DIR}/generated.txt
   ${PROJECT_BINARY_DIR}/generated_used.stamp
  DEPENDS generated.txt
  COMMENT "Using generated.txt"
  )

ADD_CUSTOM_TARGET(${PROJECT_NAME} DEPENDS generated_used.stamp)
_______________________________________________
Powered by www.kitware.com

Visit other Kitware open-source projects at 
http://www.kitware.com/opensource/opensource.html

Please keep messages on-topic and check the CMake FAQ at: 
http://www.cmake.org/Wiki/CMake_FAQ

Follow this link to subscribe/unsubscribe:
http://www.cmake.org/mailman/listinfo/cmake

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.cmake.org/pipermail/cmake/attachments/20100426/d649ba90/attachment-0001.htm>