CODEWITHSUNDEEP
cmake
feelfree
feelfree

Reputation: 11763

Why set failed in CMAKE scripts

Suppose CMAKE_BINARY_DIR = C://a//b//c, and if I run the following cmake script:

cmake_minimum_required( VERSION 2.6 )
set(project_name "hello_cmake")
project(${project_name})
add_executable(hello src/main.cpp)
 if(WIN32)
    set(CMAKE_INSTALL_PREFIX "${CMAKE_BINARY_DIR}/install" CACHE PATH "Installation Directory" )
  else()
    set(CMAKE_INSTALL_PREFIX "/usr/local" CACHE PATH "Installation Directory")
  endif()

I expect CMAKE_INSTALL_PREFIX = C://a//b//c//install if I do not define CMAKE_INSTALL_PREFIX when I first call cmake .. from the folder C://a//b//c. However, it does not work in that way, and CMAKE_INSTALL_PREFIX is given a strange folder: C://Program Files (x86)//hello_cmake. Any ideas?

Upvotes: 2

Views: 234

Answers (1)

Peter
Peter

Reputation: 14947

This is the recommended CMake incantation for handling CMAKE_INSTALL_PREFIX:

IF(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
  SET(CMAKE_INSTALL_PREFIX <path> CACHE PATH <comment> FORCE)
ENDIF(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)

Note the FORCE in the set. Apparently, the CMAKE_INSTALL_PREFIX is set fairly early in the invocation of CMake, which means it will already be set in the cache by the time you get to this line. Thus the need for FORCE.

Source is an email discussion on CMake mailing list: http://www.cmake.org/pipermail/cmake/2010-December/041135.html

Upvotes: 3

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