cdl_component <name> {
- …
-} |
A component is a configuration option that can contain additional -options and sub-components. The body of a cdl_component can contain -the same properties as that of a cdl_option. There is an additional -property, script which allows configuration data to be split into -multiple files. It is also possible for a component body to include -cdl_component, cdl_option and cdl_interface entities that should -go below this component in the configuration hierarchy.
cdl_component is implemented as a Tcl command that takes two -arguments, a name and a body. The name must be a valid C preprocessor -identifier: a sequence of upper or lower case letters, digits or -underscores, starting with a non-digit character; identifiers -beginning with an underscore should normally be avoided because they -may clash with system packages or with identifiers reserved for use by -the compiler. Within a single configuration, names must be unique. If -a configuration contained two packages which defined the same entity -CYGIMP_SOME_OPTION, any references to that entity -in a requires property or any other expression would be ambiguous. -It is possible for a given name to be used by two different packages -if those packages should never be loaded into a single configuration. -For example, architectural HAL packages are allowed to re-use certain -names because a single configuration cannot target two different -architectures. For a recommended naming convention see the Section called Package Contents and Layout in Chapter 2.
The second argument to cdl_component is a body of properties and -other commands, typically surrounded by braces so that the Tcl -interpreter treats it as a single argument. This body will be -processed by a recursive invocation of the Tcl interpreter, extended -with additional commands for the various properties that are allowed -inside a cdl_component. The valid commands are:
Allow additional control over the active state of this component.
The component's value is not directly user-modifiable, it is calculated -using a suitable CDL expression.
Define a sub-component.
Define an interface which should appear immediately below this -component in the configuration hierarchy.
Define a configuration option which should appear immediately below -this component in the configuration hierarchy.
List the source files that should be built if this component is active -and enabled.
Provide a default value for this component using a CDL expression.
Specify additional #define symbols that should go -into the owning package's configuration header file.
Control how the component's value will appear in the configuration header -file.
Use a fragment of Tcl code to output additional data to -configuration header files.
Provide a textual description for this component.
Provide a short string describing this component.
The location of on-line documentation for this component.
Specify the nature of this component.
Output a common preprocessor construct to a configuration header file.
Enabling this component provides one instance of a more general -interface.
Impose constraints on the possible values for this component.
An additional custom build step associated with this component, resulting -in a target that should not go directly into a library.
An additional custom build step associated with this component, resulting -in an object file that should go into a library.
Suppress the normal generation of a preprocessor -#define symbol in a configuration header file.
Control the location of this component in the configuration hierarchy.
List constraints that the configuration should satisfy if this component is -active and enabled.
Include additional configuration information from another -CDL script
cdl_component CYGDBG_USE_ASSERTS {
- display "Use asserts"
- default_value 1
- description "
- If this component is enabled, assertions in the code are
- tested at run-time. Assert functions (CYG_ASSERT()) are
- defined in 'include/cyg/infra/cyg_ass.h' within the 'install'
- tree. If the component is disabled, these result in no
- additional object code and no checking of the asserted
- conditions."
- script assert.cdl
-} |