[Question] link error with a simple, DOS small memory model exe, asm-main+asm-lib+c-lib, error: C symbol is missing

[LowLevelMahn]

Background: this is just a small test - the original disassembling project is much larger (~350KLOC) and currently in TASM syntax
a WASM port will hopefully come someday
tasm32 (32bit version of tasm) is used for beeing able to assemble faster on native Windows and 16bit tlink(started from dosbox) because tlink32 is not able to produce 16bit dos executables

1. my_lib.asm - single proc return_msg returning a hello... string
2. my_lib_c.c - single function c_msg returning a hello... string
3. my_exe.asm - calling the my_lib and my_lib_c procs and printing the strings

my goal is to replace tlink with wlink

all build settings (build.bat/dosbox.conf), asm/c and resulting obj/exe files available in this small test repo

git: https://github.com/LowLevelMahn/AlbertoMarnetto_seperated_restunts/tree/llm/tasm32_tests_with_binaries/src/tasm32_t
zip-download: https://github.com/LowLevelMahn/AlbertoMarnetto_seperated_restunts/archive/refs/heads/llm/tasm32_tests_with_binaries.zip
folder: src/tasm32_t

build is done like this

tasm32 my_exe.asm
tasm32 my_lib.asm
bcc /c /ms my_lib_c.c
tlink my_exe+my_lib+my_lib_c

runs and procduces a working dos exe that prints some text to the console

when i try to use (some recent) wlink like this

wlink format dos file my_exe.OBJ,my_lib.OBJ,my_lib_c.obj

i get this error

Open Watcom Linker Version 2.0 beta Feb 14 2025 02:19:26 (64-bit)
Copyright (c) 2002-2025 The Open Watcom Contributors. All Rights Reserved.
Portions Copyright (c) 1985-2002 Sybase, Inc. All Rights Reserved.
Source code is available under the Sybase Open Watcom Public License.
See https://github.com/open-watcom/open-watcom-v2#readme for details.
loading object files
Error! E2028: _C_MSG is an undefined reference
creating a DOS executable
file my_exe.OBJ(my_exe.asm): undefined symbol _C_MSG

looking at wdism result on my_lib_c the _C_MSG symblos seems defined, any idea what im doing wrong?

wdis my_lib_c.OBJ

Module: my_lib_c.c
GROUP: 'DGROUP' _DATA,_BSS

Segment: _TEXT BYTE USE16 00000008 bytes
0000                            _c_msg:
0000  55                                push            bp
0001  8B EC                             mov             bp,sp
0003  A1 00 00                          mov             ax,DGROUP:_msg_from_c
0006  5D                                pop             bp
0007  C3                                ret

Routine Size: 8 bytes,    Routine Base: _TEXT + 0000

No disassembly errors

Segment: _DATA WORD USE16 00000012 bytes
0000                            _msg_from_c:
0000  02 00                                           DW        offset DGROUP:L$1
0002                            L$1:
0002  68 65 6C 6C 6F 20 66 72 6F 6D 20 43 0D 0A 24 00 hello from C..$.

Segment: _BSS WORD USE16 00000000 bytes

BSS Size: 0 bytes

this is the output of wdism for the other 2 obj files

wdis my_exe.OBJ

Module: my_exe.asm
GROUP: 'DGROUP' STACK,_DATA

Segment: _TEXT WORD USE16 0000001C bytes
0000  B8 00 00                          mov             ax,DGROUP
0003  8E D8                             mov             ds,ax
0005  E8 00 00                          call            _TEXT:RETURN_MSG
0008  8B D0                             mov             dx,ax
000A  B4 09                             mov             ah,0x09
000C  CD 21                             int             0x21
000E  E8 00 00                          call            _TEXT:_C_MSG
0011  8B D0                             mov             dx,ax
0013  B4 09                             mov             ah,0x09
0015  CD 21                             int             0x21
0017  B8 00 4C                          mov             ax,0x4c00
001A  CD 21                             int             0x21

Routine Size: 28 bytes,    Routine Base: _TEXT + 0000

No disassembly errors

Segment: _DATA WORD USE16 00000000 bytes

Segment: STACK PARA USE16 00000400 bytes

BSS Size: 1024 bytes

wdis my_lib.OBJ

Module: my_lib.asm
GROUP: 'DGROUP' _DATA

Segment: _TEXT WORD USE16 00000004 bytes
0000                            RETURN_MSG:
0000  B8 00 00                          mov             ax,offset DGROUP:L$1
0003  C3                                ret

Routine Size: 4 bytes,    Routine Base: _TEXT + 0000

No disassembly errors

Segment: _DATA WORD USE16 00000018 bytes
0000                            L$1:
0000  48 65 6C 6C 6F 20 57 6F 72 6C 64 20 66 72 6F 6D Hello World from
0010  20 6C 69 62 21 0D 0A 24                          lib!..$

[jmalak]

the issue is simple.
by default wlink works with all symbols as case-sensitive that _c_msg and _C_MSG is two different symbols.
You have two possibility, first to use symbols in your code as case-sensitive that you fix symbol name to be exactly same (with same case) or use case-insensitive link by wlink option option NOCASEEXACT then both symbols _c_msg and _C_MSG will be same (I think it will be upper-cased).

[LowLevelMahn]

works! thanks