Open file from menu

[Rudra Banerjee <bnrj rudra yahoo com>]

Dear friends,
I am trying to create a textview that will show the file opens.
I have managed to make it read the commandline argument as:
     
    stat(argv[1], &filestat);
    buffer = (char *) malloc(filestat.st_size * sizeof (char));
    efile = fopen(argv[1], "r");
    fread(buffer, filestat.st_size, 1, efile);
    gtk_text_buffer_set_text(textbuffer, buffer, filestat.st_size);
    free(buffer);

But I am facing 2 problem(2nd problem is more important to solve). 
1) putting the above block inside "if (argv[1] != "NULL")" is giving a
segmentation fault:
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Program received signal SIGSEGV, Segmentation fault.
0x000000364066c81e in fread () from /lib64/libc.so.6

and 2) How I can open the file using file menu, instead of commandline
argument? I have defined the menu as follows:

    file = gtk_menu_item_new_with_mnemonic("_File");
    new = gtk_image_menu_item_new_from_stock(GTK_STOCK_NEW,
accel_group);
    open = gtk_image_menu_item_new_from_stock(GTK_STOCK_OPEN,
accel_group);
    sep = gtk_separator_menu_item_new();
    quit = gtk_image_menu_item_new_from_stock(GTK_STOCK_QUIT,
accel_group);

    gtk_menu_item_set_submenu(GTK_MENU_ITEM(file), filemenu);
    gtk_menu_shell_append(GTK_MENU_SHELL(filemenu), new);
    gtk_menu_shell_append(GTK_MENU_SHELL(filemenu), open);
    gtk_menu_shell_append(GTK_MENU_SHELL(filemenu), sep);
    gtk_menu_shell_append(GTK_MENU_SHELL(filemenu), quit);
    gtk_menu_shell_append(GTK_MENU_SHELL(menubar), file);
    gtk_box_pack_start(GTK_BOX(vbox), menubar, FALSE, FALSE, 3);

    g_signal_connect(G_OBJECT(new), "activate",
G_CALLBACK(filenew_activated), (gpointer) window);


    g_signal_connect(G_OBJECT(open), "activate",
G_CALLBACK(fileopen_activated), (gpointer) window);

    g_signal_connect_swapped(G_OBJECT(window), "destroy",
            G_CALLBACK(gtk_main_quit), NULL);

    g_signal_connect(G_OBJECT(quit), "activate",
            G_CALLBACK(gtk_main_quit), NULL);



which is opening the file selector, but *NOT* writing it in the
textview. I wish to open the file in textview and save it aswell after I
edit that.

If anyone kindly show the how-to, I can put problem (1) to solve later.
Please help.