小弟基础浅薄，不好意思，有一GTK基础错误盼大家指正：

camel

interface.c:
[code:1]#include "callbacks.h"
#include "interface.h"
GtkWidget *
create_fileselection (void)//创建文件选择dialog
{
        GtkWidget *fileselection;
        GtkWidget *ok_button;
        GtkWidget *cancel_button;
        fileselection =
                gtk_file_selection_new (_
                                        ("\351\200\211\346\213\251\346\226\207\344\273\266"));

        //信号连接
        g_signal_connect_swapped ((gpointer) ok_button, "clicked",
                                  G_CALLBACK (on_ok_button_clicked),
                                  GTK_OBJECT (fileselection));
}[/code:1]


//回调函数在这个文件
callbacks.c:
[code:1]#include "callbacks.h"
#include "interface.h"
#include "support.h"
void
on_ok_button_clicked (GtkButton * button, gpointer user_data)
{
        gchar *file;
        file = gtk_file_selection_get_filename (user_data);//此处编译有错
        gtk_widget_destroy (user_data);
}[/code:1]

在编译时出现如下错误是什么意思，我该如何改？？？
callbacks.c:In function 'on_ok_button_clicked':

callbacks.c:16:warning:assignment discards qualifiers from pointer target type

chaisave

请先看一下：
http://developer.gnome.org/doc/API/2.0/gtk/GtkFileSelection.html#gtk-file-selection-get-filename

callbacks.c： line 7:
-gchar *file;
+const gchar *file;

interface.c: create_fileselection (void) 没有返回任何 (GtkWidget * ) 的返回值(事实上您没有返回任何变量/常量)

camel

恍然大悟，多谢 chaisave 兄指教