ASM Community

Hi,
I have written this simple FASM program... its a small window with a textbox, a vertical scrollbar and a button (which does nothing right now). Strange thing is that I get a segfault when I compile it with the commented gtk_init line :( Using 0 for both parameters work (but I cant access argc/argv then). Any idea why?


Used the wrong words. I get the segfault when I try to run the compiled programm...:

bazik@exodus fasmpad $ make

fasm fasmpad.asm fasmpad.o

flat assembler  version 1.43

3 passes, 1942 bytes.

gcc `gtk-config --cflags --libs` fasmpad.o -o fasmpad

bazik@exodus fasmpad $ ./fasmpad 

Segmentation fault

bazik@exodus fasmpad $ gdb fasmpad

GNU gdb 5.2.1

Copyright 2002 Free Software Foundation, Inc.

GDB is free software, covered by the GNU General Public License, and you are

welcome to change it and/or distribute copies of it under certain conditions.

Type "show copying" to see the conditions.

There is absolutely no warranty for GDB.  Type "show warranty" for details.

This GDB was configured as "i686-pc-linux-gnu"...

(gdb) run

Starting program: /home/bazik/MyFiles/development/fasmpad/fasmpad 



Program received signal SIGSEGV, Segmentation fault.

0x40198064 in gdk_init_check () from /usr/lib/libgdk-1.2.so.0

(gdb) q

The program is running.  Exit anyway? (y or n) y

bazik@exodus fasmpad $ 

format ELF



include 'linux.inc'



public main



GTK_WINDOW_TOPLEVEL = 0



extrn gtk_init

extrn gtk_window_new

extrn gtk_widget_set_usize

extrn gtk_window_set_title

extrn gtk_signal_connect

extrn gtk_vbox_new

extrn gtk_hbox_new

extrn gtk_text_new

extrn gtk_text_set_editable

extrn gdk_font_load

extrn gtk_vscrollbar_new

extrn gtk_box_pack_start

extrn gtk_container_add

extrn gtk_widget_show_all

extrn gtk_main

extrn gtk_button_new_with_label

extrn gtk_main_quit

extrn exit



section '.data' writeable



	szCaption	db "FASMPAD v0.0.1", 0

	szDeleteEvent	db "delete_event", 0

	szDestroyEvent	db "destroy", 0

	szFont		db "-*-fixed-*-*-*-*-*-120-*-*-*-*-*-*", 0

	szSave		db "Save", 0



section '.bss' writeable



	nHwnd		dd ?

	nVbox		dd ?

	nHbox		dd ?

	nText		dd ?

	nFont		dd ?

	nVscroll	dd ?

	nButton		dd ?



section '.text' executable



proc main, argc,argv

	enter	

;	ccall	gtk_init, [argc], [argv] ; <-- here

	ccall	gtk_init, 0, 0



	ccall	gtk_window_new, GTK_WINDOW_TOPLEVEL

	mov	[nHwnd], eax	



	ccall	gtk_widget_set_usize, eax, 600, 400



	ccall	gtk_window_set_title, [nHwnd], szCaption



	ccall	gtk_signal_connect, [nHwnd], szDeleteEvent, DeleteEvent, 0

	ccall	gtk_signal_connect, [nHwnd], szDestroyEvent, DestroyEvent, 0



	ccall	gtk_vbox_new, 0, 0

	mov	[nVbox], eax



	ccall	gtk_hbox_new, 0, 0

	mov	[nHbox], eax



	ccall	gtk_text_new, 0, 0

	mov 	[nText], eax



	ccall	gtk_text_set_editable, [nText], 1



	ccall 	gdk_font_load, szFont

	mov	[nFont], eax



	ccall	gtk_vscrollbar_new, [nText]

	mov	[nVscroll], eax

	ccall	gtk_box_pack_start, [nHbox], [nText], 1, 1, 0

	ccall	gtk_box_pack_start, [nHbox], [nVscroll], 0, 0, 0



	ccall	gtk_button_new_with_label, szSave

	mov	[nButton], eax



	ccall	gtk_box_pack_start, [nVbox], [nHbox], 1, 1, 0

	ccall   gtk_box_pack_start, [nVbox], [nButton], 0, 0, 0



	ccall	gtk_container_add, [nHwnd], [nVbox]

	ccall 	gtk_widget_show_all, [nHwnd]



	call	gtk_main

	ccall	exit, 0



proc DeleteEvent

	enter

	xor	eax,eax

	return



proc DestroyEvent

	enter

	call	gtk_main_quit

	return

Makefile:

fasmpad: fasmpad.o

	gcc `gtk-config --cflags --libs` fasmpad.o -o fasmpad

fasmpad.o: fasmpad.asm linux.inc

	fasm fasmpad.asm fasmpad.o

Linux.inc (Privalovs ccall.inc... just renamed it ;) )

macro proc name,[arg]			; define procedure

 { common

    name:

    virtual at ebp+8

    if ~ arg eq

   forward

     local ..arg

     ..arg dd ?

     arg equ ..arg

   common

     end if

    end virtual

    local ..dynamic_data,..dynamic_size

    dynamic_data equ ..dynamic_data

    dynamic_size equ ..dynamic_size

    virtual at ebp - dynamic_size

     dynamic_data: }



macro enter				; begin procedure instructions

 { dynamic_size = $ - dynamic_data

   end virtual

   enter dynamic_size,0 }



macro return				; return from procedure

 { leave

   ret }



macro ccall proc,[arg]			; call procedure

 { common local size

   size = 0

   reverse

   push arg

   size = size+4

   common

   call proc

   add esp,size }

I'm not very familiar with fasm and not at all with linux programming but doesn't gtk_init need its parameters by reference? It seems like you are passing the values of argc and argv to it while you should pass the addresses of them both :confused:

Thomas

I got it to work!!! (At least I think so...) :)

lea eax, [ebp+12]

lea ebx, [ebp+8]

call gtk_init, ebx, eax

seems to work too, no segment fault. I think a bove three lines work, I tried to pass "--display --sync -gtk-debug" to the app and I got "Gtk-WARNING **: cannot open display: --sync".

When playing around a little i made this (see attachment), it sets the app caption to argv[0]. I made that and then realized how I could do.
N.B! The file is a .tgz archive!

Thanks a lot Privalov :alright:

I should refresh my C knowledge ;)

A windows programm with just a GUI will look the same ;)

There will be some "true assembly" in it when I wrote some functions behind the GUI :P
Already extended the above code with a File/Edit/Format/Help menu and a statusbar. I'll just write a small "Notepad"-Clone in FASM for training ;)
Think like file reading/saving will happen through kernel interrups (using C functions would make it too easy :P )

This maybe a bit oftopic but yet realted (since I've seen thins that look like classes, at lest if you just look at the names, eg GtkContainerClass), what diiffers a structure form a class?
And does classes exist in C or did they arrive in C++?

I Think I might just have to google for some C-programming books this weekend and learn some C, somehow I think I'm gonna need it...