MantisBT - CMake
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IDProjectCategoryView StatusDate SubmittedLast Update
0016026CMake(No Category)public2016-03-20 14:352016-06-10 14:31
ReporterStephen Kelly 
Assigned ToKitware Robot 
PrioritynormalSeverityminorReproducibilityhave not tried
StatusclosedResolutionmoved 
PlatformOSOS Version
Product Version 
Target VersionFixed in Version 
Summary0016026: CMake provides no reliable variable for 'the file a function is declared in'
Description
Given

  $ cat cmake/thefunc.cmake

  set(somevar "${CMAKE_CURRENT_LIST_DIR}")

  function(thefunc)
    message("somevar: ${somevar}")
    message("listdir: ${CMAKE_CURRENT_LIST_DIR}")
  endfunction()

  $ cat dir1/CMakeLists.txt

  include(thefunc)

  thefunc()

  include(GenerateExportHeader)

  $ cat CMakeLists.txt

  cmake_minimum_required(VERSION 2.8.12)

  project(ttt CXX)

  list(APPEND CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake)

  add_subdirectory(dir1)

  thefunc()

  if (COMMAND generate_export_header)
    add_library(foo foo.cpp)
    generate_export_header(foo)
  endif()

the build output is

  somevar: /home/stephen/dev/src/playground/cmake/cmake
  listdir: /home/stephen/dev/src/playground/cmake/dir1
  somevar:
  listdir: /home/stephen/dev/src/playground/cmake
  CMake Error: File /exportheader.cmake.in does not exist.
  CMake Error at /home/stephen/dev/prefix/qtbase/kde/share/cmake-3.5/Modules/GenerateExportHeader.cmake:362 (configure_file):
    configure_file Problem configuring file
  Call Stack (most recent call first):
    /home/stephen/dev/prefix/qtbase/kde/share/cmake-3.5/Modules/GenerateExportHeader.cmake:378 (_do_generate_export_header)
    CMakeLists.txt:14 (generate_export_header)


  -- Configuring incomplete, errors occurred!


That is: CMake doesn't provide a way to determine the file a macro or function is defined in. The workaround is to determine that outside of the function/macro scope. However, that workaround breaks down because the variable and the function/macro do not follow the same scoping rules. The function/macro is available 'globally' after definition, so users can make the mistake of trying to use it in a scope which does not contain the `include()`.

This affects at least the GenerateExportHeader module and perhaps other modules shipped with cmake.

One workaround is to check the existence of the variable in the function:

 https://git.reviewboard.kde.org/r/127432/diff/1 [^]

Another would be to use a global property instead of a variable for the workaround.

A better solution may be for cmake to provide the 'path of the file this code resides in' in a variable.
Steps To Reproduce
Additional Information
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Issue History
Date ModifiedUsernameFieldChange
2016-03-20 14:35Stephen KellyNew Issue
2016-06-10 14:29Kitware RobotNote Added: 0042967
2016-06-10 14:29Kitware RobotStatusnew => resolved
2016-06-10 14:29Kitware RobotResolutionopen => moved
2016-06-10 14:29Kitware RobotAssigned To => Kitware Robot
2016-06-10 14:31Kitware RobotStatusresolved => closed

Notes
(0042967)
Kitware Robot   
2016-06-10 14:29   
Resolving issue as `moved`.

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