configure_file¶
Copy a file to another location and modify its contents.
configure_file(<input> <output>
[NO_SOURCE_PERMISSIONS | USE_SOURCE_PERMISSIONS |
FILE_PERMISSIONS <permissions>...]
[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
#cmakedefine VAR ...
will be replaced with either
#define VAR ...
or
/* #undef VAR */
depending on whether VAR
is set in CMake to any value not considered
a false constant by the if()
command. The "..." content on the
line after the variable name, if any, is processed as above.
Unlike lines of the form #cmakedefine VAR ...
, in lines of the form
#cmakedefine01 VAR
, VAR
itself will expand to VAR 0
or VAR 1
rather than being assigned the value ...
. Therefore, input lines of the form
#cmakedefine01 VAR
will be replaced with either
#define VAR 0
or
#define VAR 1
Input lines of the form #cmakedefine01 VAR ...
will expand
as #cmakedefine01 VAR ... 0
or #cmakedefine01 VAR ... 0
,
which may lead to undefined behavior.
New in version 3.10: The result lines (with the exception of the #undef
comments) can be
indented using spaces and/or tabs between the #
character
and the cmakedefine
or cmakedefine01
words. This whitespace
indentation will be preserved in the output lines:
# cmakedefine VAR
# cmakedefine01 VAR
will be replaced, if VAR
is defined, with
# define VAR
# define VAR 1
If the input file is modified the build system will re-run CMake to re-configure the file and generate the build system again. The generated file is modified and its timestamp updated on subsequent cmake runs only if its content is changed.
The arguments are:
<input>
Path to the input file. A relative path is treated with respect to the value of
CMAKE_CURRENT_SOURCE_DIR
. The input path must be a file, not a directory.<output>
Path to the output file or directory. A relative path is treated with respect to the value of
CMAKE_CURRENT_BINARY_DIR
. If the path names an existing directory the output file is placed in that directory with the same file name as the input file. If the path contains non-existent directories, they are created.NO_SOURCE_PERMISSIONS
New in version 3.19.
Do not transfer the permissions of the input file to the output file. The copied file permissions default to the standard 644 value (-rw-r--r--).
USE_SOURCE_PERMISSIONS
New in version 3.20.
Transfer the permissions of the input file to the output file. This is already the default behavior if none of the three permissions-related keywords are given (
NO_SOURCE_PERMISSIONS
,USE_SOURCE_PERMISSIONS
orFILE_PERMISSIONS
). TheUSE_SOURCE_PERMISSIONS
keyword mostly serves as a way of making the intended behavior clearer at the call site.FILE_PERMISSIONS <permissions>...
New in version 3.20.
Ignore the input file's permissions and use the specified
<permissions>
for the output file instead.COPYONLY
Copy the file without replacing any variable references or other content. This option may not be used with
NEWLINE_STYLE
.ESCAPE_QUOTES
Escape any substituted quotes with backslashes (C-style).
@ONLY
Restrict variable replacement to references of the form
@VAR@
. This is useful for configuring scripts that use${VAR}
syntax.NEWLINE_STYLE <style>
Specify the newline style for the output file. Specify
UNIX
orLF
for\n
newlines, or specifyDOS
,WIN32
, orCRLF
for\r\n
newlines. This option may not be used withCOPYONLY
.
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>
.