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Updated: Wednesday, February 9, 2022
 
 

glib-genmarshal (1)

Name

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

Synopsis

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

Description

GLIB-GENMARSHAL(1)               User Commands              GLIB-GENMARSHAL(1)



NAME
       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
       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.

USING GLIB-GENMARSHAL WITH MESON
       Meson supports generating closure marshallers using glib-genmarshal out
       of the box in its "gnome" module.

       In your meson.build file you will typically call the gnome.genmarshal()
       method with the source list of marshallers to generate:

           gnome = import('gnome')
           marshal_files = gnome.genmarshal('marshal',
             sources: 'marshal.list',
             internal: true,
           )

       The marshal_files variable will contain an array of two elements in the
       following order:

       o   a build target for the source file

       o   a build target for the header file

       You should use the returned objects to provide a dependency on every
       other build target that references the source or header file; for
       instance, if you are using the source to build a library:

           mainlib = library('project',
             sources: project_sources + marshal_files,
             ...
           )

       Additionally, if you are including the generated header file inside a
       build target that depends on the library you just built, you must
       ensure that the internal dependency includes the generated header as a
       required source file:

           mainlib_dep = declare_dependency(sources: marshal_files[1], link_with: mainlib)

       You should not include the generated source file as well, otherwise it
       will be built separately for every target that depends on it, causing
       build failures. To know more about why all this is required, please
       refer to the corresponding Meson FAQ entry[1].

       For more information on how to use the method, see the Meson
       documentation for gnome.genmarshal()[2].

USING GLIB-GENMARSHAL WITH AUTOTOOLS
       In order to use glib-genmarshal in your project when using Autotools as
       the build system, you will first need to modify your configure.ac file
       to ensure you find the appropriate command using pkg-config, similarly
       as to how you discover the compiler and linker flags for GLib.

           PKG_PROG_PKG_CONFIG([0.28])

           PKG_CHECK_VAR([GLIB_GENMARSHAL], [glib-2.0], [glib_genmarshal])

       In your Makefile.am file you will typically need very simple rules to
       generate the C files needed for the build.

           marshal.h: marshal.list
                   $(AM_V_GEN)$(GLIB_GENMARSHAL) \
                           --header \
                           --output=$@ \
                           $<

           marshal.c: marshal.list marshal.h
                   $(AM_V_GEN)$(GLIB_GENMARSHAL) \
                           --include-header=marshal.h \
                           --body \
                           --output=$@ \
                           $<

           BUILT_SOURCES += marshal.h marshal.c
           CLEANFILES += marshal.h marshal.c
           EXTRA_DIST += marshal.list

       In the example above, the first rule generates the header file and
       depends on a marshal.list file in order to regenerate the result in
       case the marshallers list is updated. The second rule generates the
       source file for the same marshal.list, and includes the file generated
       by the header rule.

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);


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+------------------+
       |ATTRIBUTE TYPE | ATTRIBUTE VALUE  |
       +---------------+------------------+
       |Availability   | library/glib2    |
       +---------------+------------------+
       |Stability      | Uncommitted      |
       +---------------+------------------+

SEE ALSO
       glib-mkenums(1)

NOTES
        1. corresponding Meson FAQ entry
           https://mesonbuild.com/FAQ.html#how-do-i-tell-meson-that-my-sources-use-generated-headers

        2. Meson documentation for gnome.genmarshal()
           https://mesonbuild.com/Gnome-module.html#gnomegenmarshal


       Source code for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-
       code-downloads.html.

       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from
       https://download.gnome.org/sources/glib/2.66/glib-2.66.8.tar.xz.

       Further information about this software can be found on the open source
       community website at https://wiki.gnome.org/Projects/GLib/.



GObject                                                     GLIB-GENMARSHAL(1)