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name: feature
long_name: Feature option object
since: 0.47.0
description: Meson object representing a [`feature` options](Build-options.md#features)
methods:
- name: enabled
returns: bool
description: Returns whether the feature was set to `'enabled'`
- name: disabled
returns: bool
description: Returns whether the feature was set to `'disabled'`
- name: auto
returns: bool
description: Returns whether the feature was set to `'auto'`
- name: allowed
since: 0.59.0
returns: bool
description: Returns whether the feature was set to `'enabled'` or `'auto'`
- name: disable_auto_if
since: 0.59.0
returns: feature
description: |
Returns the feature, with `'auto'` converted to `'disabled'` if value is true.
| Feature | `value = true` | `value = false` |
| -------- | -------------- | --------------- |
| Auto | Disabled | Auto |
| Enabled | Enabled | Enabled |
| Disabled | Disabled | Disabled |
example: |
`disable_auto_if` is useful to give precedence to mutually exclusive dependencies
(that provide the same API) if either or both are available:
```
# '-Dfoo=auto -Dbar=enabled' will not pick foo even if installed.
use_bar = get_option('bar')
use_foo = get_option('foo').disable_auto_if(use_bar.enabled())
dep_foo = dependency('foo', required: use_foo)
if not dep_foo.found()
dep_foo = dependency('bar', required: use_bar)
endif
```
posargs:
value:
type: bool
description: See the table above
- name: enable_auto_if
since: 1.1.0
returns: feature
description: |
Returns the feature, with `'auto'` converted to `'enabled'` if value is true.
| Feature | `value = true` | `value = false` |
| -------- | -------------- | --------------- |
| Auto | Enabled | Auto |
| Enabled | Enabled | Enabled |
| Disabled | Disabled | Disabled |
posargs:
value:
type: bool
description: See the table above
- name: require
returns: feature
since: 0.59.0
description: |
Returns the object itself if the value is true; an error if the object is
`'enabled'` and the value is false; a disabled feature if the object
is `'auto'` or `'disabled'` and the value is false.
| Feature | `value = true` | `value = false` |
| -------- | -------------- | --------------- |
| Auto | Auto | Disabled |
| Enabled | Enabled | Error |
| Disabled | Disabled | Disabled |
example: |
`require` is useful to restrict the applicability of `'auto'` features,
for example based on other features or on properties of the host machine:
```
if get_option('directx').require(host_machine.system() == 'windows',
error_message: 'DirectX only available on Windows').allowed() then
src += ['directx.c']
config.set10('HAVE_DIRECTX', true)
endif
```
posargs:
value:
type: bool
description: The value to check
kwargs:
error_message:
type: str
default: "''"
description: The error message to print if the check fails
- name: enable_if
returns: feature
since: 1.1.0
description: |
Returns the object itself if the value is false; an error if the object is
`'disabled'` and the value is true; an enabled feature if the object
is `'auto'` or `'enabled'` and the value is true.
| Feature | `value = true` | `value = false` |
| -------- | -------------- | --------------- |
| Auto | Enabled | Auto |
| Enabled | Enabled | Enabled |
| Disabled | Error | Disabled |
example: |
`enable_if` is useful to restrict the applicability of `'auto'` features,
particularly when passing them to [[dependency]]:
```
use_llvm = get_option('llvm').enable_if(with_clang).enable_if(with_llvm_libs)
dep_llvm = dependency('llvm', required: use_llvm)
```
posargs:
value:
type: bool
description: The value to check
kwargs:
error_message:
type: str
default: "''"
description: The error message to print if the check fails
- name: disable_if
returns: feature
since: 1.1.0
description: |
Returns the object itself if the value is false; an error if the object is
`'enabled'` and the value is true; a disabled feature if the object
is `'auto'` or `'disabled'` and the value is true.
| Feature | `value = true` | `value = false` |
| -------- | -------------- | --------------- |
| Auto | Disabled | Auto |
| Enabled | Error | Enabled |
| Disabled | Disabled | Disabled |
This is equivalent to `feature_opt.require(not condition)`, but may make
code easier to reason about, especially when mixed with `enable_if`
example: |
`disable_if` is useful to restrict the applicability of `'auto'` features,
particularly when passing them to [[dependency]]:
```
use_os_feature = get_option('foo') \
.disable_if(host_machine.system() == 'darwin', error_message : 'os feature not supported on MacOS')
dep_os_feature = dependency('os_feature', required: use_os_feature)
```
posargs:
value:
type: bool
description: The value to check
kwargs:
error_message:
type: str
default: "''"
description: The error message to print if the check fails