File manipulation command.
Reading file(READ <filename> <out-var> [...]) file(STRINGS <filename> <out-var> [...]) file(<HASH> <filename> <out-var>) file(TIMESTAMP <filename> <out-var> [...]) Writing file({WRITE | APPEND} <filename> <content>...) file({TOUCH | TOUCH_NOCREATE} [<file>...]) file(GENERATE OUTPUT <output-file> [...]) Filesystem file({GLOB | GLOB_RECURSE} <out-var> [...] [<globbing-expr>...]) file(RENAME <oldname> <newname>) file({REMOVE | REMOVE_RECURSE } [<files>...]) file(MAKE_DIRECTORY [<dir>...]) file({COPY | INSTALL} <file>... DESTINATION <dir> [...]) Path Conversion file(RELATIVE_PATH <out-var> <directory> <file>) file({TO_CMAKE_PATH | TO_NATIVE_PATH} <path> <out-var>) Transfer file(DOWNLOAD <url> <file> [...]) file(UPLOAD <file> <url> [...]) Locking file(LOCK <path> [...])
file(READ <filename> <variable> [OFFSET <offset>] [LIMIT <max-in>] [HEX])
Read content from a file called <filename>
and store it in a <variable>
. Optionally start from the given <offset>
and read at most <max-in>
bytes. The HEX
option causes data to be converted to a hexadecimal representation (useful for binary data).
file(STRINGS <filename> <variable> [<options>...])
Parse a list of ASCII strings from <filename>
and store it in <variable>
. Binary data in the file are ignored. Carriage return (\r
, CR) characters are ignored. The options are:
LENGTH_MAXIMUM <max-len>
LENGTH_MINIMUM <min-len>
LIMIT_COUNT <max-num>
LIMIT_INPUT <max-in>
LIMIT_OUTPUT <max-out>
<variable>
.NEWLINE_CONSUME
\n
, LF) as part of string content instead of terminating at them.NO_HEX_CONVERSION
REGEX <regex>
ENCODING <encoding-type>
For example, the code
file(STRINGS myfile.txt myfile)
stores a list in the variable myfile
in which each item is a line from the input file.
file(<HASH> <filename> <variable>)
Compute a cryptographic hash of the content of <filename>
and store it in a <variable>
. The supported <HASH>
algorithm names are those listed by the string(<HASH>) command.
file(TIMESTAMP <filename> <variable> [<format>] [UTC])
Compute a string representation of the modification time of <filename>
and store it in <variable>
. Should the command be unable to obtain a timestamp variable will be set to the empty string (“”).
See the string(TIMESTAMP)
command for documentation of the <format>
and UTC
options.
file(WRITE <filename> <content>...) file(APPEND <filename> <content>...)
Write <content>
into a file called <filename>
. If the file does not exist, it will be created. If the file already exists, WRITE
mode will overwrite it and APPEND
mode will append to the end. Any directories in the path specified by <filename>
that do not exist will be created.
If the file is a build input, use the configure_file()
command to update the file only when its content changes.
file(TOUCH [<files>...]) file(TOUCH_NOCREATE [<files>...])
Create a file with no content if it does not yet exist. If the file already exists, its access and/or modification will be updated to the time when the function call is executed.
Use TOUCH_NOCREATE to touch a file if it exists but not create it. If a file does not exist it will be silently ignored.
With TOUCH and TOUCH_NOCREATE the contents of an existing file will not be modified.
file(GENERATE OUTPUT output-file <INPUT input-file|CONTENT content> [CONDITION expression])
Generate an output file for each build configuration supported by the current CMake Generator
. Evaluate generator expressions
from the input content to produce the output content. The options are:
CONDITION <condition>
0
or 1
after evaluating generator expressions.CONTENT <content>
INPUT <input-file>
CMAKE_CURRENT_SOURCE_DIR
. See policy CMP0070
.OUTPUT <output-file>
$<CONFIG>
to specify a configuration-specific output file name. Multiple configurations may generate the same output file only if the generated content is identical. Otherwise, the <output-file>
must evaluate to an unique name for each configuration. A relative path (after evaluating generator expressions) is treated with respect to the value of CMAKE_CURRENT_BINARY_DIR
. See policy CMP0070
.Exactly one CONTENT
or INPUT
option must be given. A specific OUTPUT
file may be named by at most one invocation of file(GENERATE)
. Generated files are modified and their timestamp updated on subsequent cmake runs only if their content is changed.
Note also that file(GENERATE)
does not create the output file until the generation phase. The output file will not yet have been written when the file(GENERATE)
command returns, it is written only after processing all of a project’s CMakeLists.txt
files.
file(GLOB <variable> [LIST_DIRECTORIES true|false] [RELATIVE <path>] [CONFIGURE_DEPENDS] [<globbing-expressions>...]) file(GLOB_RECURSE <variable> [FOLLOW_SYMLINKS] [LIST_DIRECTORIES true|false] [RELATIVE <path>] [CONFIGURE_DEPENDS] [<globbing-expressions>...])
Generate a list of files that match the <globbing-expressions>
and store it into the <variable>
. Globbing expressions are similar to regular expressions, but much simpler. If RELATIVE
flag is specified, the results will be returned as relative paths to the given path. The results will be ordered lexicographically.
If the CONFIGURE_DEPENDS
flag is specified, CMake will add logic to the main build system check target to rerun the flagged GLOB
commands at build time. If any of the outputs change, CMake will regenerate the build system.
By default GLOB
lists directories - directories are omitted in result if LIST_DIRECTORIES
is set to false.
Note
We do not recommend using GLOB to collect a list of source files from your source tree. If no CMakeLists.txt file changes when a source is added or removed then the generated build system cannot know when to ask CMake to regenerate. The CONFIGURE_DEPENDS
flag may not work reliably on all generators, or if a new generator is added in the future that cannot support it, projects using it will be stuck. Even if CONFIGURE_DEPENDS
works reliably, there is still a cost to perform the check on every rebuild.
Examples of globbing expressions include:
*.cxx - match all files with extension cxx *.vt? - match all files with extension vta,...,vtz f[3-5].txt - match files f3.txt, f4.txt, f5.txt
The GLOB_RECURSE
mode will traverse all the subdirectories of the matched directory and match the files. Subdirectories that are symlinks are only traversed if FOLLOW_SYMLINKS
is given or policy CMP0009
is not set to NEW
.
By default GLOB_RECURSE
omits directories from result list - setting LIST_DIRECTORIES
to true adds directories to result list. If FOLLOW_SYMLINKS
is given or policy CMP0009
is not set to OLD
then LIST_DIRECTORIES
treats symlinks as directories.
Examples of recursive globbing include:
/dir/*.py - match all python files in /dir and subdirectories
file(RENAME <oldname> <newname>)
Move a file or directory within a filesystem from <oldname>
to <newname>
, replacing the destination atomically.
file(REMOVE [<files>...]) file(REMOVE_RECURSE [<files>...])
Remove the given files. The REMOVE_RECURSE
mode will remove the given files and directories, also non-empty directories. No error is emitted if a given file does not exist.
file(MAKE_DIRECTORY [<directories>...])
Create the given directories and their parents as needed.
file(<COPY|INSTALL> <files>... DESTINATION <dir> [FILE_PERMISSIONS <permissions>...] [DIRECTORY_PERMISSIONS <permissions>...] [NO_SOURCE_PERMISSIONS] [USE_SOURCE_PERMISSIONS] [FILES_MATCHING] [[PATTERN <pattern> | REGEX <regex>] [EXCLUDE] [PERMISSIONS <permissions>...]] [...])
The COPY
signature copies files, directories, and symlinks to a destination folder. Relative input paths are evaluated with respect to the current source directory, and a relative destination is evaluated with respect to the current build directory. Copying preserves input file timestamps, and optimizes out a file if it exists at the destination with the same timestamp. Copying preserves input permissions unless explicit permissions or NO_SOURCE_PERMISSIONS
are given (default is USE_SOURCE_PERMISSIONS
).
See the install(DIRECTORY)
command for documentation of permissions, FILES_MATCHING
, PATTERN
, REGEX
, and EXCLUDE
options. Copying directories preserves the structure of their content even if options are used to select a subset of files.
The INSTALL
signature differs slightly from COPY
: it prints status messages (subject to the CMAKE_INSTALL_MESSAGE
variable), and NO_SOURCE_PERMISSIONS
is default. Installation scripts generated by the install()
command use this signature (with some undocumented options for internal use).
file(RELATIVE_PATH <variable> <directory> <file>)
Compute the relative path from a <directory>
to a <file>
and store it in the <variable>
.
file(TO_CMAKE_PATH "<path>" <variable>) file(TO_NATIVE_PATH "<path>" <variable>)
The TO_CMAKE_PATH
mode converts a native <path>
into a cmake-style path with forward-slashes (/
). The input can be a single path or a system search path like $ENV{PATH}
. A search path will be converted to a cmake-style list separated by ;
characters.
The TO_NATIVE_PATH
mode converts a cmake-style <path>
into a native path with platform-specific slashes (\
on Windows and /
elsewhere).
Always use double quotes around the <path>
to be sure it is treated as a single argument to this command.
file(DOWNLOAD <url> <file> [<options>...]) file(UPLOAD <file> <url> [<options>...])
The DOWNLOAD
mode downloads the given <url>
to a local <file>
. The UPLOAD
mode uploads a local <file>
to a given <url>
.
Options to both DOWNLOAD
and UPLOAD
are:
INACTIVITY_TIMEOUT <seconds>
LOG <variable>
SHOW_PROGRESS
STATUS <variable>
;
separated list of length 2. The first element is the numeric return value for the operation, and the second element is a string value for the error. A 0
numeric error means no error in the operation.TIMEOUT <seconds>
USERPWD <username>:<password>
HTTPHEADER <HTTP-header>
NETRC <level>
Specify whether the .netrc file is to be used for operation. If this option is not specified, the value of the CMAKE_NETRC
variable will be used instead. Valid levels are:
IGNORED
OPTIONAL
REQUIRED
NETRC_FILE <file>
NETRC
level is OPTIONAL
or REQUIRED
. If this option is not specified, the value of the CMAKE_NETRC_FILE
variable will be used instead.If neither NETRC
option is given CMake will check variables CMAKE_NETRC
and CMAKE_NETRC_FILE
, respectively.
Additional options to DOWNLOAD
are:
EXPECTED_HASH ALGO=<value>
ALGO
is one of the algorithms supported by file(<HASH>)
. If it does not match, the operation fails with an error. EXPECTED_MD5 <value>
EXPECTED_HASH MD5=<value>
.TLS_VERIFY <ON|OFF>
https://
URLs. The default is to not verify.TLS_CAINFO <file>
https://
URLs.For https://
URLs CMake must be built with OpenSSL support. TLS/SSL
certificates are not checked by default. Set TLS_VERIFY
to ON
to check certificates and/or use EXPECTED_HASH
to verify downloaded content. If neither TLS
option is given CMake will check variables CMAKE_TLS_VERIFY
and CMAKE_TLS_CAINFO
, respectively.
file(LOCK <path> [DIRECTORY] [RELEASE] [GUARD <FUNCTION|FILE|PROCESS>] [RESULT_VARIABLE <variable>] [TIMEOUT <seconds>])
Lock a file specified by <path>
if no DIRECTORY
option present and file <path>/cmake.lock
otherwise. File will be locked for scope defined by GUARD
option (default value is PROCESS
). RELEASE
option can be used to unlock file explicitly. If option TIMEOUT
is not specified CMake will wait until lock succeed or until fatal error occurs. If TIMEOUT
is set to 0
lock will be tried once and result will be reported immediately. If TIMEOUT
is not 0
CMake will try to lock file for the period specified by <seconds>
value. Any errors will be interpreted as fatal if there is no RESULT_VARIABLE
option. Otherwise result will be stored in <variable>
and will be 0
on success or error message on failure.
Note that lock is advisory - there is no guarantee that other processes will respect this lock, i.e. lock synchronize two or more CMake instances sharing some modifiable resources. Similar logic applied to DIRECTORY
option - locking parent directory doesn’t prevent other LOCK
commands to lock any child directory or file.
Trying to lock file twice is not allowed. Any intermediate directories and file itself will be created if they not exist. GUARD
and TIMEOUT
options ignored on RELEASE
operation.
© 2000–2018 Kitware, Inc. and Contributors
Licensed under the BSD 3-clause License.
https://cmake.org/cmake/help/v3.12/command/file.html