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Expected behaviour of #cmakedefine

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Ian Cullen

Expected behaviour of #cmakedefine

Hi,

I'm trying to create a header file containing version number details but
am not sure if the following behaviour is expected or a bug.

Simplified example has 2 files

==> CMakeLists.txt <==
cmake_minimum_required(VERSION 3.11)
project (
   VersionTest
   VERSION 1.0.4
   )

configure_file (
   "${PROJECT_SOURCE_DIR}/config.h.in"
   "${PROJECT_BINARY_DIR}/config.h"
   @ONLY
   )

==> config.h.in <==
#cmakedefine VersionTest_VERSION_MAJOR @VersionTest_VERSION_MAJOR@
#cmakedefine VersionTest_VERSION_MINOR @VersionTest_VERSION_MINOR@
#define VersionTest_VERSION_MINOR @VersionTest_VERSION_MINOR@

Running cmake creates the output file as required but it has the
following contents

==> config.h <==
#define VersionTest_VERSION_MAJOR 1
/* #undef VersionTest_VERSION_MINOR */
#define VersionTest_VERSION_MINOR 0

Looking at the manual
(https://cmake.org/cmake/help/v3.12/command/configure_file.html), this
appears to be because the number '0' is considered false by the if()
command, however '0' is valid within a version number, so perhaps should
not be considered false in this context.

Is this a known issue? Is it recommended to use #define rather than
#cmakedefine for these types of files?

Thanks

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J. Caleb Wherry

Re: Expected behaviour of #cmakedefine

I suppose it all depends on if there are situations where you don’t want those variables set? To me, it doesn’t make sense to ever not have version numbers set so I would use #define.

-Caleb

On Wed, Aug 15, 2018 at 8:32 AM Ian Cullen <[hidden email]> wrote:

Hi,

I'm trying to create a header file containing version number details but
am not sure if the following behaviour is expected or a bug.

Simplified example has 2 files

==> CMakeLists.txt <==
cmake_minimum_required(VERSION 3.11)
project (
   VersionTest
   VERSION 1.0.4
   )

configure_file (
   "${PROJECT_SOURCE_DIR}/config.h.in"
   "${PROJECT_BINARY_DIR}/config.h"
   @ONLY
   )

==> config.h.in <==
#cmakedefine VersionTest_VERSION_MAJOR @VersionTest_VERSION_MAJOR@
#cmakedefine VersionTest_VERSION_MINOR @VersionTest_VERSION_MINOR@
#define VersionTest_VERSION_MINOR @VersionTest_VERSION_MINOR@

Running cmake creates the output file as required but it has the
following contents

==> config.h <==
#define VersionTest_VERSION_MAJOR 1
/* #undef VersionTest_VERSION_MINOR */
#define VersionTest_VERSION_MINOR 0

Looking at the manual
(https://cmake.org/cmake/help/v3.12/command/configure_file.html), this
appears to be because the number '0' is considered false by the if()
command, however '0' is valid within a version number, so perhaps should
not be considered false in this context.

Is this a known issue? Is it recommended to use #define rather than
#cmakedefine for these types of files?

Thanks

--

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

Kitware offers various services to support the CMake community. For more information on each offering, please visit:

CMake Support: http://cmake.org/cmake/help/support.html
CMake Consulting: http://cmake.org/cmake/help/consulting.html
CMake Training Courses: http://cmake.org/cmake/help/training.html

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Sent from my iPhone 4s

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Powered by www.kitware.com

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Kitware offers various services to support the CMake community. For more information on each offering, please visit:

CMake Support: http://cmake.org/cmake/help/support.html
CMake Consulting: http://cmake.org/cmake/help/consulting.html
CMake Training Courses: http://cmake.org/cmake/help/training.html

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Ian Cullen

Re: Expected behaviour of #cmakedefine

Agreed, version numbers will never not be set so #define is the better choice in this case. However this seems like an easy thing for users to trip-up on, particularly as only #cmakedefine is used in the configure_file() manual page.

Perhaps an additional example, or an INFO/WARNING section in the manual to highlight this 'issue'?

On 15/08/2018 13:56, J. Caleb Wherry wrote:

I suppose it all depends on if there are situations where you don’t want those variables set? To me, it doesn’t make sense to ever not have version numbers set so I would use #define.

-Caleb

On Wed, Aug 15, 2018 at 8:32 AM Ian Cullen <[hidden email]> wrote:

Hi,

I'm trying to create a header file containing version number details but
am not sure if the following behaviour is expected or a bug.

Simplified example has 2 files

==> CMakeLists.txt <==
cmake_minimum_required(VERSION 3.11)
project (
   VersionTest
   VERSION 1.0.4
   )

configure_file (
   "${PROJECT_SOURCE_DIR}/config.h.in"
   "${PROJECT_BINARY_DIR}/config.h"
   @ONLY
   )

==> config.h.in <==
#cmakedefine VersionTest_VERSION_MAJOR @VersionTest_VERSION_MAJOR@
#cmakedefine VersionTest_VERSION_MINOR @VersionTest_VERSION_MINOR@
#define VersionTest_VERSION_MINOR @VersionTest_VERSION_MINOR@

Running cmake creates the output file as required but it has the
following contents

==> config.h <==
#define VersionTest_VERSION_MAJOR 1
/* #undef VersionTest_VERSION_MINOR */
#define VersionTest_VERSION_MINOR 0

Looking at the manual
(https://cmake.org/cmake/help/v3.12/command/configure_file.html), this
appears to be because the number '0' is considered false by the if()
command, however '0' is valid within a version number, so perhaps should
not be considered false in this context.

Is this a known issue? Is it recommended to use #define rather than
#cmakedefine for these types of files?

Thanks

--

Powered by www.kitware.com

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

Kitware offers various services to support the CMake community. For more information on each offering, please visit:

CMake Support: http://cmake.org/cmake/help/support.html
CMake Consulting: http://cmake.org/cmake/help/consulting.html
CMake Training Courses: http://cmake.org/cmake/help/training.html

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

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

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