gthread使用注意

1、初始化gthread
      if (!g_thread_supported ()) //如果gthread没有被初始化
             g_thread_init (NULL);  //进行初始化
      gdk_threads_init ();        //初始化GDK多线程，这样可以在多线程中使用成对的gdk_threads_enter()和gdk_thread_leave(),在Gtk程序保证          gdk_threads_init()在main loop执行之前执行，为了保证线程安全应该在gtk_init()之前调用，g_thread_init()必须在函数gdk_threads_init()之前执行。
2、gdk_threads_enter()和gdk_threads_leave()
  　gdk_threads_enter()这是一宏定义，占领临界区，这样使Gdk和Gtk+函数在多线程中被安全的调用而不会造成竞争条件，保证数据安全，一次只能有一线程访问临界区。gdk_threads_leave释放对当前临界区访问。
     在调用任何与gtk相关函数时，需要使用gdk_threads_enter()和gdk_threads_leave()成对的宏，保证当前函数的的调用只可能在一个线程中。
3、示例如下：

       #include <glib.h> #include <gtk/gtk.h> #include <libgnomevfs/gnome-vfs.h> #define BUF_SIZE 4096 GtkWidget *window; GtkWidget *image = NULL; GtkWidget *vbox = NULL; const gchar *uri = "/home/cspark/logo-large.png"; void callback (void) { g_print ("%d %s/n", __LINE__, __FUNCTION__); } void thread_func (GtkWidget *button) { int i; for (i = 0; i <= 20; i++) { sleep (1); gchar *s = g_strdup_printf ("Test %d", i); gdk_threads_enter (); gtk_button_set_label (GTK_BUTTON (button), s); gdk_threads_leave (); if (s) { g_free (s); s = NULL; } } } void load_image () { GnomeVFSHandle *handle; GnomeVFSResult result; GdkPixbufLoader *loader; GdkPixbuf *pixbuf; gchar buffer[BUF_SIZE]; GnomeVFSFileSize bytes_read; result = gnome_vfs_open (&handle, uri, GNOME_VFS_OPEN_READ); loader = gdk_pixbuf_loader_new (); while (result == GNOME_VFS_OK) { result = gnome_vfs_read (handle, buffer, BUF_SIZE, &bytes_read); gdk_pixbuf_loader_write (loader, buffer, bytes_read, NULL); sleep (2); } gdk_pixbuf_loader_close (loader, NULL); pixbuf = gdk_pixbuf_loader_get_pixbuf (loader); if (!pixbuf) { g_print ("pixbuf is NULl"); return; } gdk_threads_enter (); image = gtk_image_new_from_pixbuf (pixbuf); gtk_box_pack_start (GTK_BOX (vbox), image, FALSE, FALSE, 0); gtk_widget_show (image); gdk_threads_leave (); } int main (int argc, char *argv[]) { if (!g_thread_supported ()) g_thread_init (NULL); gdk_threads_init(); gdk_threads_enter (); gtk_init (&argc, &argv); gnome_vfs_init (); window = gtk_window_new (GTK_WINDOW_TOPLEVEL); g_signal_connect (window, "destroy", gtk_main_quit, NULL); GtkWidget *button = NULL; button = gtk_button_new_with_label ("Test Mutilate GThread"); vbox = gtk_vbox_new (FALSE, 0); gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0); g_signal_connect (button, "clicked", (GCallback)(callback), NULL); gtk_widget_show (button); gtk_container_add (GTK_CONTAINER (window), vbox); gtk_widget_show_all (window); g_thread_create ((GThreadFunc) (load_image), NULL, FALSE, NULL); g_thread_create ((GThreadFunc) (thread_func), button, FALSE, NULL); gtk_main (); gdk_threads_leave (); return 0; } 

 

Makefile:

CC=gcc CFLAGS = `pkg-config --cflags gtk+-2.0 gthread-2.0 gnome-vfs-2.0` -g LDFLAGS = `pkg-config --libs gtk+-2.0 gthread-2.0 gnome-vfs-2.0` -rdynamic SRC=gnomevfs-test.c test:$(SRC) $(CC) $(CFLAGS) $(LDFLAGS) $(SRC) -o test