CMAKE_INSTALL_MODEΒΆ

New in version 3.22.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

The CMAKE_INSTALL_MODE environment variable allows users to operate CMake in an alternate mode of file(INSTALL) and install().

The default behavior for an installation is to copy a source file from a source directory into a destination directory. This environment variable however allows the user to override this behavior, causing CMake to create symbolic links instead.

Note

A symbolic link consists of a reference file path rather than contents of its own, hence there are two ways to express the relation, either by a relative or an absolute path.

The following values are allowed for CMAKE_INSTALL_MODE:

  • empty, unset or COPY: default behavior, duplicate the file at its destination
  • ABS_SYMLINK: create an absolute symbolic link to the source file at the destination or fail
  • ABS_SYMLINK_OR_COPY: like ABS_SYMLINK but silently copy on error
  • REL_SYMLINK: create an relative symbolic link to the source file at the destination or fail
  • REL_SYMLINK_OR_COPY: like REL_SYMLINK but silently copy on error
  • SYMLINK: try as if through REL_SYMLINK and fall back to ABS_SYMLINK if the referenced file cannot be expressed using a relative path. Fail on error.
  • SYMLINK_OR_COPY: like SYMLINK but silently copy on error

Installing symbolic links rather than copying files can help conserve storage space because files do not have to be duplicated on disk. However, modifications applied to the source immediately affects the symbolic link and vice versa. Use with caution.

Note

CMAKE_INSTALL_MODE only affects files, not directories.

Note

Symbolic links are not available on all platforms.