CMake 笔记

1. configure_file

configure_file()让你可以在代码文件中使用CMake中定义的变量。

configure_file(<input> <output>
                    [COPYONLY] [ESCAPE_QUOTES] [@ONLY]
                    [NEWLINE_STYLE [UNIX|DOS|WIN32|LF|CRLF] ])

Copies an <input> file to an <output> file and substitutes variable values referenced as @VAR@ or ${VAR} in the input file content.
Each variable reference will be replaced with the current value of the variable, or the empty string if the variable is not defined.
Furthermore, input lines of the form:

拷贝一个 <input>（输入文件） 文件到 <output> （输出文件），并且替换输入文件中被 @VAR@ 或者 ${VAR} 引用的变量值。每一个变量将被替换成当前的变量值（注：CMake中的变量值）或者空串当变量未定义。

输入文件中的

#cmakedefine VAR ...

将被替换为

#define VAR ...

或者

/* #undef VAR */

Example

Consider a source tree containing a foo.h.in file:
#cmakedefine FOO_ENABLE
#cmakedefine FOO_STRING "@FOO_STRING@"
An adjacent CMakeLists.txt may use configure_file to configure the header:
option(FOO_ENABLE "Enable Foo" ON)
if(FOO_ENABLE)
  set(FOO_STRING "foo")
endif()
configure_file(foo.h.in foo.h @ONLY)
This creates a foo.h in the build directory corresponding to this source directory. If the FOO_ENABLE option is on, the configured file will contain:
#define FOO_ENABLE
#define FOO_STRING "foo"
Otherwise it will contain:
/* #undef FOO_ENABLE */
/* #undef FOO_STRING */
One may then use the include_directories() command to specify the output directory as an include directory:
include_directories(${CMAKE_CURRENT_BINARY_DIR})
so that sources may include the header as #include <foo.h>.

configure_file(
  "${PROJECT_SOURCE_DIR}/cmake/config/config.h.in"
  "${PROJECT_BINARY_DIR}/include/config/config.h"
)