Q45710: L2002 When Linking Small Model Main with Other Memory Models

Article: Q45710
Product(s): See article
Version(s): 5.10   | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | S_QuickC | mspl13_c
Last Modified: 14-AUG-1989

An attempt to link a module that has been compiled in the small memory
model with a module compiled in the medium or large memory model
produces the following error:

   L2002: fixup overflow

The cause, in this particular case, of the "fixup overflow" error
message is not documented in the C Version 5.10 "CodeView and
Utilities, Microsoft Editor, Mixed-Language Programming Guide" on Page
366.

Normally, you should NOT link programs that contain different memory
models. All modules should be compiled using the same memory model.
(It is possible to use the "near" and "far" keywords to produce
mixed-model programs, but this is tricky and usually doesn't give much
performance gain.)

If the following module, MOD1.C

    #include<stdio.h>

    void main(void);

    void main()
    {
        printf(" module 1 \n");
        mod2();
    }

is linked with the module, MOD2.C

    #include<stdio.h>

    void mod2(void);

    void mod2()
    {
        printf(" module 2 \n");
    }

in various memory models, the following results occur:

    Memory Model      Result
    ------------      ------
    MOD1  | MOD2
    ------|-----
          |
     /AS  | /AM       L2002 : fixup overflow
          |
     /AS  | /AL       L2002 : fixup overflow
          |
     /AM  | /AS       Links, hangs on run
          |
     /AM  | /AL       Executes normally
          |
     /AL  | /AS       Links, hangs on run
          |
     /AL  | /AM       Links, prints trash for MOD2 on run