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extern dynamic linking

Started by gesho, March 07, 2020, 01:01:38 AM

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gesho

I am trying to link to external method using extern. Here is a link of my two files:
https://www.dropbox.com/sh/90xvrvfvruj79u8/AADMW8o8vjJJy3Cy-YPjEFFEa?dl=0

hello.asm is trying to call subroutine from gsm-string.asm

I compile with

ml /c .\hello.asm
ml /c .\gsm-string.asm

I'm getting *.obj files but I can't make last step, link to work. Typically I get
>  link /subsystem:console /out:hello.exe hello.obj gsm-string.obj
hello.obj : fatal error LNK1190: invalid fixup found, type 0x0002

As I understand dynamic linking should be possible here. What should link command line be? Or something is wrong in code?

PS: I tried posting this in Irvine forum before but go no response. Re-posting here, since this place is more active.

hutch--

Activity is not the problem, its whether anyone is familiar with the Irvine book to help you. Do not make duplicate posts.

gesho

Thanks.

Irvine book is not really needed in any way for this question. It's a bare-bone code with only a single call. Just knowing what it takes to make extern to work.

hutch--

Try this.

Ml.exe /c /coff source.asm

EXTERN or EXTERNDEF is normaly not used in win32.

gesho

still the same error, something goes off when linking.

what would be a way to link dynamically if not extern?

_japheth

The problem is simple: when masm starts, it assumes any external is 16-bit. After the ".386" and ".model flat" lines, it has switched to 32-bit. So all you have to do is to place your externals BEHIND the ".model flat,..." line:


.386
.model flat, stdcall

... here come your PROTOs, EXTERNs and EXTERNDEFs ...


There are more errors, however. For example, a missing RET in the called procedure...
Dummheit, gepaart mit Dreistigkeit - eine furchtbare Macht.

hutch--

Three files.

    .686p
    .MODEL flat, stdcall

    ExitProcess PROTO, dwExitCode: DWORD
    TestString PROTO

    includelib \masm32\lib\kernel32.lib

    .data
      gString byte "some string"

    .code

    start:

    main PROC
      mov eax, 12
      call TestString
      INVOKE ExitProcess,0
      ret
    main ENDP

    END start



    .386
    .model flat, stdcall

  .data

  .code
    TestString PROC
       mov eax,7777h
        ret                        ; I forgot to put this in.
    TestString ENDP
  END


The batch file to build both.


@echo off

if exist "source.obj" del "source.obj"
if exist "source.exe" del "source.exe"

\masm32\bin\ml /c /coff "source.asm"
\masm32\bin\ml /c /coff "tststr.asm"

dir "source.*"

\masm32\bin\Link /SUBSYSTEM:CONSOLE /OPT:NOREF "source.obj" "tststr.obj"
dir "source.*"

pause


RESULT


Microsoft (R) Macro Assembler Version 6.15.8803
Copyright (C) Microsoft Corp 1981-2000.  All rights reserved.

Assembling: source.asm
Microsoft (R) Macro Assembler Version 6.15.8803
Copyright (C) Microsoft Corp 1981-2000.  All rights reserved.

Assembling: tststr.asm
Volume in drive K is disk3_k
Volume Serial Number is 68C7-4DBB

Directory of K:\asm32\$000

07/03/2020  01:32 AM               351 source.asm
07/03/2020  01:35 AM               661 source.obj
               2 File(s)          1,012 bytes
               0 Dir(s)  743,519,244,288 bytes free
Microsoft (R) Incremental Linker Version 5.12.8078
Copyright (C) Microsoft Corp 1992-1998. All rights reserved.

Volume in drive K is disk3_k
Volume Serial Number is 68C7-4DBB

Directory of K:\asm32\$000

07/03/2020  01:32 AM               351 source.asm
07/03/2020  01:35 AM             2,560 source.exe
07/03/2020  01:35 AM               661 source.obj
               3 File(s)          3,572 bytes
               0 Dir(s)  743,519,240,192 bytes free
Press any key to continue . . .


hutch--

Just as a note, when you create 2 modules in this manner and link them with link.exe, you are STATICALLY linking the two modules, dynamic linking is done with a DLL.

gesho

hutch--, _japheth: you guys are cooler then (hot) toasted bread.

This all got it working under both alternatives, using extern or proto.

/OPT:REF/NOREF was new and useful.