GEN_BRIDGE_METADATA(1) BSD General Commands Manual GEN_BRIDGE_METADATA(1)
NAME
gen_bridge_metadata -- Objective-C Bridges Metadata Generator
SYNOPSIS
gen_bridge_metadata [options...] headers...
DESCRIPTION
gen_bridge_metadata is a tool that generates bridging metadata information for a given framework or set
of headers. The Objective-C bridges supported in Mac OS X, such as RubyCocoa (Ruby) and PyObjC
(Python), read this information at runtime.
Metadata files describe the parts of an Objective-C framework that the bridges cannot automatically
handle. These are primarily the ANSI C elements of the framework -- functions, constants, enumerations,
and so on -- but also include special cases such as functions or methods that accept pointer-like argu-ments. arguments.
ments. These special cases must be manually specified in separate files called exceptions. The
gen_bridge_metadata tool can then read in the exceptions file when it generates the framework metadata.
The file extension used for metadata files should be .bridgesupport.
Certain elements, such as inline functions, cannot be described in the metadata files. It is therefore
required to generate a dynamic library in order to make the bridges use them. The gen_bridge_metadata
tool can take care of that for you.
The file extension for the dynamic libraries should be .dylib.
You should install metadata files in one of three filesystem locations. For example, for a framework
named MyFramework that is installed as /Library/Frameworks/MyFramework.framework, you can install the
MyFramework.bridgesupport and MyFramework.dylib files in one of the following possible locations, in
order of priority:
oo /Library/Frameworks/MyFramework/Resources/BridgeSupport
oo /Library/BridgeSupport
oo ~/Library/BridgeSupport
OPTIONS
The gen_bridge_metadata tool accepts the following command-line options:
-f framework, --framework framework
Generates metadata for the given framework. This argument can accept both the name of a framework
of an absolute path to a framework. When passing a framework name, the program will try to locate
the framework in one of the standard framework locations.
-p, --private
Generates metadata based on the private headers of the given frameworks. This argument must be
used with the -f argument.
-F format, --format format
Selects the metadata format that will be generated. Possible values are:
final The final metadata format. This is the default value.
dylib The dynamic library format. This is only required if you want to support
inline functions. In order to use this format you need to pass a value for
the -o argument.
exceptions-template This will generate an exception template. Please consult BridgeSupport(5) for
more details about the exception format. Once your exception file is finished
you can pass it to the -e argument in order to generate the final metadata.
-e file, --exception file
Considers the given exception file when generating the final metadata format. The given exception
file must conform to a certain format, described in bridgeSupport(5). Exception files are manu-ally manually
ally written, but you can generate a template by passing -F exceptions-template to the generator.
--64-bit
Writes 64-bit annotations to the final metadata format. In order to use this option you need to
run the generator on a 64-bit machine. The generation will take a bit more than twice the time, as
it will have to collect both 32-bit and 64-bit annotations, and then merge them into a single doc-ument. document.
ument.
-c, --cflags flags
Provides custom flags that will be passed to the C compiler. The generator compiles and executes
several C and Objective-C programs during the generation of the final metadata format. Some flags
are determined by default, but you might want to provide your own flags according to the piece of
code you want to generate metadata for (for example, a framework part of a umbrella framework).
-C, --cflags-64 flags
Provides custom flags that will be passed to the C compiler, when generating 64-bit annotations.
By default the same flags are passed to the C compiler when generating both 32-bit and 64-bit
annotations.
-o, --output file
Writes the output to the given file. This argument is mandatory when generating the ``dylib'' for-mat. format.
mat. For other formats, by default the output is redirected to the standard output.
-h, --help
Prints a summary of the options.
-d, --debug
Turns on debugging messages. You probably don't want to enable this option, unless you are going
to debug the metadata generator.
-v, --version
Shows the version of the program. The version is also marked in generated metadata files, as the
``version'' attribute of the ``signatures'' top-level element.
EXAMPLES
This generates bridge support metadata for a custom framework:
mkdir -p /Path/To/YourFramework.framework/Resources/BridgeSupport
gen_bridge_metadata -f /Path/To/YourFramework.framework -o
/Path/To/YourFramework.framework/Resources/BridgeSupport/YourFramework.bridgesupport
If the custom framework has inline functions and you want to be able to call them, here is how you can
generate a ``dylib'' file:
gen_bridge_metadata -f /Path/To/YourFramework.framework -F dylib -o
/Path/To/YourFramework.framework/Resources/BridgeSupport/YourFramework.dylib
It is also possible to generate bridge support metadata for a standalone C library (here, libcurl):
gen_bridge_metadata -c '-lcurl -I/usr/include/curl' /usr/include/curl/*.h >
/Library/BridgeSupport/curl.bridgesupport
SEE ALSO
BridgeSupport(5) /System/Library/DTDs/BridgeSupport.dtd ruby(1) python(1)
BSD November 2, 2006 BSD
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