# target_compile_options

Add compile options to a target.

    target_compile_options(<target> [BEFORE]
      {INTERFACE|PUBLIC|PRIVATE} <item>...
      [{INTERFACE|PUBLIC|PRIVATE} <item>...]...)

Adds options to the `COMPILE_OPTIONS` or `INTERFACE_COMPILE_OPTIONS` target properties. These options are used when compiling the given `<target>`, which must have been created by a command such as `add_executable()` or `add_library()` and must not be an ALIAS target.

Note

These options are not used when linking the target. See the `target_link_options()` command for that.

## Arguments

If `BEFORE` is specified, the content will be prepended to the property instead of being appended. See policy `CMP0101` which affects whether `BEFORE` will be ignored in certain cases.

The `INTERFACE`, `PUBLIC` and `PRIVATE` keywords are required to specify the scope of the following arguments. `PRIVATE` and `PUBLIC` items will populate the `COMPILE_OPTIONS` property of `<target>`. `PUBLIC` and `INTERFACE` items will populate the `INTERFACE_COMPILE_OPTIONS` property of `<target>`. The following arguments specify compile options. Repeated calls for the same `<target>` append items in the order called.

Added in version 3.11: Allow setting `INTERFACE` items on IMPORTED targets.

Arguments to `target_compile_options` may use generator expressions with the syntax `$<...>`. See the `cmake-generator-expressions(7)` manual for available expressions. See the `cmake-buildsystem(7)` manual for more on defining buildsystem properties.

## Option De-duplication

The final set of options used for a target is constructed by accumulating options from the current target and the usage requirements of its dependencies. The set of options is de-duplicated to avoid repetition.

Added in version 3.12: While beneficial for individual options, the de-duplication step can break up option groups. For example, `-option A -option B` becomes `-option A B`. One may specify a group of options using shell-like quoting along with a `SHELL:` prefix. The `SHELL:` prefix is dropped, and the rest of the option string is parsed using the `separate_arguments()` `UNIX_COMMAND` mode. For example, `"SHELL:-option A" "SHELL:-option B"` becomes `-option A -option B`.

## See Also

- This command can be used to add any options. However, for adding preprocessor definitions and include directories it is recommended to use the more specific commands `target_compile_definitions()` and `target_include_directories()`.

- For directory-wide settings, there is the command `add_compile_options()`.

- For file-specific settings, there is the source file property `COMPILE_OPTIONS`.

- This command adds compile options for all languages in a target. Use the `COMPILE_LANGUAGE` generator expression to specify per-language compile options.

- `target_compile_features()`

- `target_link_libraries()`

- `target_link_directories()`

- `target_link_options()`

- `target_precompile_headers()`

- `target_sources()`

- `CMAKE_<LANG>_FLAGS` and `CMAKE_<LANG>_FLAGS_<CONFIG>` add language-wide flags passed to all invocations of the compiler. This includes invocations that drive compiling and those that drive linking.

- The `CheckCompilerFlag` module to check whether the compiler supports a given flag.