cdl_option <name> {
- compile [-library=libxxx.a] <list of files>
- …
-} |
The compile property allows component developers to specify source -files which should be compiled and added to one of the target -libraries. Usually each source file will end up the library -libtarget.a. It is possible for component writers -to specify an alternative library for an entire package using the -library property. Alternatively -the desired library can be specified on the compile line itself. For -example, to add a particular source file to the -libextras.a library the following could be used:
cdl_package CYGPKG_IO_SERIAL {
- …
- compile -library=libextras.a common/tty.c
-} |
Details of the build process including such issues as compiler flags -and the order in which things happen can be found in -Chapter 4.
compile properties can occur in any of cdl_option, -cdl_component, cdl_package or cdl_interface. A compile -property has effect if and only if the entity that contains it is -active and enabled. Typically the body of a cdl_package will define -any source files that need to be built irrespective of individual -options, and each cdl_component, cdl_option, and cdl_interface -will define source files that are more specific. A single compile -property can list any number of source files, all destined for the -same library. A cdl_option or other entity can contain multiple -compile properties, each of which can specify a different library. -It is possible for a given source file to be specified in compile -properties for several different options, in which case the source -file will get built if any of these options are active and enabled.
If the package follows the directory -layout conventions then the configuration tools will search for -the specified source files first in the -src subdirectory of the -package, then relative to the package directory itself.
Note: A shortcoming of the current specification of compile properties is -that there is no easy way to specify source files that should be built -unless an option is enabled. It would sometimes be useful to be able -to say: “if option A is enabled then compile -file x.c, otherwise compile file -y.c. There are two simple ways of achieving this:
Always compile y.c, typically by listing it in -the body of the cdl_package, but use -#ifndef A to produce an empty object file if -option A is not enabled. This has the big -disadvantage that the file always gets compiled and hence for some -configurations builds will take longer than necessary.
Use a calculated option whose value is !A, and -have a compile y.c property in its body. This -has the big disadvantage of adding another calculated option to the -configuration.
It is likely that this will be resolved in the future, possibly by -using some sort of expression as the argument to a compile property.
Note: Currently it is not possible to control the priority of a compile -property, in other words the order in which a file gets compiled -relative to other build steps. This functionality might prove useful -for complicated packages and should be added.
cdl_package CYGPKG_INFRA {
- display "Infrastructure"
- include_dir cyg/infra
- description "
- Common types and useful macros.
- Tracing and assertion facilities.
- Package startup options."
-
- compile startup.cxx prestart.cxx pkgstart.cxx userstart.cxx \
- dummyxxmain.cxx memcpy.c memset.c delete.cxx \
- diag.cxx tcdiag.cxx
-} |