glib-genmarshal: GObject Reference Manual

glib-genmarshal

glib-genmarshal — C code marshaller generation utility for GLib closures

Synopsis

glib-genmarshal [OPTION...] [FILE...]

Description

glib-genmarshal is a small utility that generates C code marshallers for callback functions of the GClosure mechanism in the GObject sublibrary of GLib. The marshaller functions have a standard signature, they get passed in the invoking closure, an array of value structures holding the callback function parameters and a value structure for the return value of the callback. The marshaller is then responsible to call the respective C code function of the closure with all the parameters on the stack and to collect its return value.

glib-genmarshal takes a list of marshallers to generate as input. The marshaller list is either read from files passed as additional arguments on the command line; or from standard input, by using - as the input file.

Marshaller list format

The marshaller lists are processed line by line, a line can contain a comment in the form of

1	# this is a comment

or a marshaller specification of the form

RTYPE:PTYPE
RTYPE:PTYPE,PTYPE
RTYPE:PTYPE,PTYPE,PTYPE

The RTYPE part specifies the callback's return type and the PTYPEs right to the colon specify the callback's parameter list, except for the first and the last arguments which are always pointers.

Parameter types

Currently, the following types are supported:

`VOID`	indicates no return type, or no extra parameters. If `VOID` is used as the parameter list, no additional parameters may be present.
`BOOLEAN`	for boolean types (gboolean)
`CHAR`	for signed char types (gchar)
`UCHAR`	for unsigned char types (guchar)
`INT`	for signed integer types (gint)
`UINT`	for unsigned integer types (guint)
`LONG`	for signed long integer types (glong)
`ULONG`	for unsigned long integer types (gulong)
`INT64`	for signed 64bit integer types (gint64)
`UINT64`	for unsigned 64bit integer types (guint64)
`ENUM`	for enumeration types (gint)
`FLAGS`	for flag enumeration types (guint)
`FLOAT`	for single-precision float types (gfloat)
`DOUBLE`	for double-precision float types (gdouble)
`STRING`	for string types (gchar*)
`BOXED`	for boxed (anonymous but reference counted) types (GBoxed*)
`PARAM`	for GParamSpec or derived types (GParamSpec*)
`POINTER`	for anonymous pointer types (gpointer)
`OBJECT`	for GObject or derived types (GObject*)
`VARIANT`	for GVariant types (GVariant*)
`NONE`	deprecated alias for `VOID`
`BOOL`	deprecated alias for `BOOLEAN`

Options

`--header`	Generate header file contents of the marshallers. This option is mutually exclusive with the `--body` option.
`--body`	Generate C code file contents of the marshallers. This option is mutually exclusive with the `--header` option.
`--prefix=PREFIX`	Specify marshaller prefix. The default prefix is `g_cclosure_user_marshal'.
`--skip-source`	Skip source location remarks in generated comments.
`--stdinc`	Use the standard marshallers of the GObject library, and include `glib-object.h` in generated header files. This option is mutually exclusive with the `--nostdinc` option.
`--nostdinc`	Do not use the standard marshallers of the GObject library, and skip `glib-object.h` include directive in generated header files. This option is mutually exclusive with the `--stdinc` option.
`--internal`	Mark generated functions as internal, using `G_GNUC_INTERNAL`.
`--valist-marshallers`	Generate valist marshallers, for use with `g_signal_set_va_marshaller()`.
`-v`, `--version`	Print version information.
`--g-fatal-warnings`	Make warnings fatal, that is, exit immediately once a warning occurs.
`-h`, `--help`	Print brief help and exit.
`-v`, `--version`	Print version and exit.
`--output=FILE`	Write output to `FILE` instead of the standard output.
`--prototypes`	Generate function prototypes before the function definition in the C source file, in order to avoid a `missing-prototypes` compiler warning. This option is only useful when using the `--body` option.
`--pragma-once`	Use the `once` pragma instead of an old style header guard when generating the C header file. This option is only useful when using the `--header` option.
`--include-header=HEADER`	Adds a `#include` directive for the given file in the C source file. This option is only useful when using the `--body` option.
`-D SYMBOL[=VALUE]`	Adds a `#define` C pre-processor directive for `SYMBOL` and its given `VALUE`, or "1" if the value is unset. You can use this option multiple times; if you do, all the symbols will be defined in the same order given on the command line, before the symbols undefined using the `-U` option. This option is only useful when using the `--body` option.
`-U SYMBOL`	Adds a `#undef` C pre-processor directive to undefine the given `SYMBOL`. You can use this option multiple times; if you do, all the symbols will be undefined in the same order given on the command line, after the symbols defined using the `-D` option. This option is only useful when using the `--body` option.
`--quiet`	Minimizes the output of glib-genmarshal, by printing only warnings and errors. This option is mutually exclusive with the `--verbose` option.
`--verbose`	Increases the verbosity of glib-genmarshal, by printing debugging information. This option is mutually exclusive with the `--quiet` option.

Example

To generate marshallers for the following callback functions:

void   foo (gpointer data1,
            gpointer data2);
void   bar (gpointer data1,
            gint     param1,
            gpointer data2);
gfloat baz (gpointer data1,
            gboolean param1,
            guchar   param2,
            gpointer data2);

The marshaller.list file has to look like this:

VOID:VOID
VOID:INT
FLOAT:BOOLEAN,UCHAR

and you call glib-genmarshal like this:

glib-genmarshal --header marshaller.list > marshaller.h
glib-genmarshal --body marshaller.list > marshaller.c

The generated marshallers have the arguments encoded in their function name. For this particular list, they are

g_cclosure_user_marshal_VOID__VOID(...),
g_cclosure_user_marshal_VOID__INT(...),
g_cclosure_user_marshal_FLOAT__BOOLEAN_UCHAR(...).

They can be used directly for GClosures or be passed in as the GSignalCMarshaller c_marshaller; argument upon creation of signals:

GClosure *cc_foo, *cc_bar, *cc_baz;

cc_foo = g_cclosure_new (NULL, foo, NULL);
g_closure_set_marshal (cc_foo, g_cclosure_user_marshal_VOID__VOID);
cc_bar = g_cclosure_new (NULL, bar, NULL);
g_closure_set_marshal (cc_bar, g_cclosure_user_marshal_VOID__INT);
cc_baz = g_cclosure_new (NULL, baz, NULL);
g_closure_set_marshal (cc_baz, g_cclosure_user_marshal_FLOAT__BOOLEAN_UCHAR);