使用GLib的G_DEFINE_INTERFACE为何出现未定义引用错误？

我正在学习GObject接口定义，编写了一个最小化的Fruit接口代码，包含头文件fruit.h和实现文件fruit.c：

fruit.h #

#pragma once

#include <glib-object.h>

G_BEGIN_DECLS

#define EXAMPLE_TYPE_FRUIT example_fruit_get_type ()
G_DECLARE_INTERFACE (ExampleFruit, example_fruit, EXAMPLE, FRUIT, GObject)

struct _ExampleFruitInterface
{
  GTypeInterface parent_iface;

  char *flavour;

  void (*eat) (ExampleFruit *self);
};

void example_fruit_eat (ExampleFruit *self);

G_END_DECLS

fruit.c #

#include "fruit.h"

#include <stdio.h>

G_DEFINE_INTERFACE (ExampleFruit, example_fruit, G_TYPE_OBJECT)

static void
example_fruit_default_init (ExampleFruitInterface *iface)
{
  // Nothing to do?
}

void
example_fruit_eat (ExampleFruit *self)
{
  ExampleFruitInterface *iface;

  g_return_if_fail (EXAMPLE_IS_FRUIT (self));

  iface = EXAMPLE_FRUIT_GET_IFACE (self);
  printf ("Non nom, so %s\n", iface->flavour);
}

编译时出现链接错误，错误信息如下：

[3/4] Linking target src/gobject-inheritance
FAILED: src/gobject-inheritance 
cc  -o src/gobject-inheritance src/gobject-inheritance.p/fruit.c.o src/gobject-inheritance.p/main.c.o -L/app/lib -Wl,--as-needed -Wl,--no-undefined /usr/lib/x86_64-linux-gnu/libglib-2.0.so
/usr/lib/gcc/x86_64-unknown-linux-gnu/14.2.0/../../../../x86_64-unknown-linux-gnu/bin/ld: src/gobject-inheritance.p/fruit.c.o: in function `EXAMPLE_IS_FRUIT':
/mnt/storage/Programming/.gnome-builder/projects/gobject-inheritance/builds/org.gnome.Example.json-flatpak-org.freedesktop.Platform-24.08-x86_64-main/../../../../../gobject-inheritance/src/fruit.h:8:(.text+0x61): undefined reference to `g_type_check_instance_is_a'
/usr/lib/gcc/x86_64-unknown-linux-gnu/14.2.0/../../../../x86_64-unknown-linux-gnu/bin/ld: src/gobject-inheritance.p/fruit.c.o: in function `EXAMPLE_FRUIT_GET_IFACE':
/mnt/storage/Programming/.gnome-builder/projects/gobject-inheritance/builds/org.gnome.Example.json-flatpak-org.freedesktop.Platform-24.08-x86_64-main/../../../../../gobject-inheritance/src/fruit.h:8:(.text+0x8f): undefined reference to `g_type_interface_peek'
/usr/lib/gcc/x86_64-unknown-linux-gnu/14.2.0/../../../../x86_64-unknown-linux-gnu/bin/ld: src/gobject-inheritance.p/fruit.c.o: in function `example_fruit_get_type':
/mnt/storage/Programming/.gnome-builder/projects/gobject-inheritance/builds/org.gnome.Example.json-flatpak-org.freedesktop.Platform-24.08-x86_64-main/../../../../../gobject-inheritance/src/fruit.c:5:(.text+0x127): undefined reference to `g_type_register_static_simple'
/usr/lib/gcc/x86_64-unknown-linux-gnu/14.2.0/../../../../x86_64-unknown-linux-gnu/bin/ld: /mnt/storage/Programming/.gnome-builder/projects/gobject-inheritance/builds/org.gnome.Example.json-flatpak-org.freedesktop.Platform-24.08-x86_64-main/../../../../../gobject-inheritance/src/fruit.c:5:(.text+0x140): undefined reference to `g_type_interface_add_prerequisite'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

使用Meson构建，当前配置如下：

根目录meson.build #

project('gobject-inheritance', 'c',
          version: '0.1.0',
    meson_version: '>= 1.0.0',
  default_options: [ 'warning_level=2', 'werror=false', 'c_std=gnu11', ],
)

cc = meson.get_compiler('c')

subdir('src')

src/meson.build #

gobject_inheritance_sources = [
  'fruit.c',
  'fruit.h',
  'main.c',
]

gobject_inheritance_deps = [
  dependency('glib-2.0'),
]

executable('gobject-inheritance', gobject_inheritance_sources,
  dependencies: gobject_inheritance_deps,
  install: true,
)

构建环境为Freedesktop 24.08 SDK，请问如何解决这些未定义引用错误？

这些未定义的函数（g_type_check_instance_is_a、g_type_interface_peek等）属于GObject库，而非基础GLib库。当前仅添加了glib-2.0依赖，缺少gobject-2.0的链接依赖。

修改src/meson.build中的依赖列表，添加gobject-2.0：

gobject_inheritance_deps = [
  dependency('glib-2.0'),
  dependency('gobject-2.0'),
]

或更简洁地直接使用glib-2.0的gobject组件：

gobject_inheritance_deps = dependency('glib-2.0', components: ['gobject'])

重新运行meson setup --reconfigure和ninja即可解决链接错误。

内容的提问来源于stack exchange，提问作者Newbyte