How to fix masm32: error LNK2001: unresolved external symbol - api

Question

I'm creating an app to test an api func IsCharLowerA and then output res using MessageBoxA. I'm using masm32.
link /SUBSYSTEM:WINDOWS kod.obj
Microsoft (R) Incremental Linker Version 5.12.8078
Copyright (C) Microsoft Corp 1992-1998. All rights reserved.
kod.obj : warning LNK4033: converting object format from OMF to COFF
kod.obj : error LNK2001: unresolved external symbol __ExitProcess#4
kod.obj : error LNK2001: unresolved external symbol __MessageBoxA#16
kod.obj : error LNK2001: unresolved external symbol __imp__printf
kod.obj : error LNK2001: unresolved external symbol __imp__scanf
kod.obj : error LNK2001: unresolved external symbol _IsCharLowerA#4
LINK : error LNK2001: unresolved external symbol _WinMainCRTStartup
ml kod.asm
Microsoft (R) Macro Assembler Version 6.14.8444
Copyright (C) Microsoft Corp 1981-1997. All rights reserved.
Assembling: kod.asm
Microsoft (R) Incremental Linker Version 5.12.8078
Copyright (C) Microsoft Corp 1992-1998. All rights reserved.
/z2
"kod.obj"
"kod.exe"
NUL
LINK : warning LNK4044: unrecognized option "z2"; ignored
kod.obj : warning LNK4033: converting object format from OMF to COFF
LINK : fatal error LNK1181: cannot open input file "kod.exe"
I've tried to use microsoft masm32 (to compile code in visual studio), but when the app starts it's only ask for a char and then closes. I could not try to debug due to "source not available" error.
Some code:
.586
.model flat, stdcall
option casemap: none
include C:\masm32\include\windows.inc
include C:\masm32\include\kernel32.inc
include C:\masm32\include\user32.inc
include C:\masm32\include\msvcrt.inc
includelib C:\masm32\lib\msvcrt.lib
includelib C:\masm32\lib\kernel32.lib
includelib C:\masm32\lib\user32.lib
.data
msg db 'Enter char: ', 0
messagebox_title db ' Лабораторна робота № 5 ', 0
result_0 db ' NOT LOWERCASE ', 0
result_1 db ' LOWERCASE ', 0
scan_modifier db '%c', 0
.data?
scan_res dd ?
.code
start:
push ebp
mov ebp, esp
invoke crt_printf, OFFSET msg
invoke crt_scanf, OFFSET scan_modifier, scan_res
push scan_res
call IsCharLowerA
push 0
push offset messagebox_title
cmp eax, 0
jne notNULL
push offset result_0
jmp next
notNULL:
push offset result_1
next:
push 0
call MessageBoxA
push 0
call ExitProcess
pop ebp
end start
Update #1: (changed MessageBoxA -> MessageBoxA#16 and others)
Code:
.586
.model flat, stdcall
option casemap: none
include C:\masm32\include\windows.inc
include C:\masm32\include\kernel32.inc
include C:\masm32\include\user32.inc
include C:\masm32\include\msvcrt.inc
includelib C:\masm32\lib\msvcrt.lib
includelib C:\masm32\lib\kernel32.lib
includelib C:\masm32\lib\user32.lib
extrn MessageBoxA#16 : PROC
extrn ExitProcess#4 : PROC
.data
msg db 'Enter char: ', 0
messagebox_title db ' Лабораторна робота № 5 ', 0
result_0 db ' NOT LOWERCASE ', 0
result_1 db ' LOWERCASE ', 0
scan_modifier db '%c', 0
.data?
scan_res dd ?
.code
start:
push ebp
mov ebp, esp
invoke crt_printf, OFFSET msg
invoke crt_scanf, OFFSET scan_modifier, scan_res
push scan_res
call IsCharLowerA
push 0
push offset messagebox_title
cmp eax, 0
jne notNULL
push offset result_0
jmp next
notNULL:
push offset result_1
next:
push 0
call MessageBoxA#16
push 0
call ExitProcess#4
pop ebp
end start
Res:
link /SUBSYSTEM:WINDOWS kod.obj
Microsoft (R) Incremental Linker Version 5.12.8078
Copyright (C) Microsoft Corp 1992-1998. All rights reserved.
kod.obj : warning LNK4033: converting object format from OMF to COFF
kod.obj : error LNK2001: unresolved external symbol _MessageBoxA#16
kod.obj : error LNK2001: unresolved external symbol __imp__printf
kod.obj : error LNK2001: unresolved external symbol _ExitProcess#4
kod.obj : error LNK2001: unresolved external symbol __imp__scanf
kod.obj : error LNK2001: unresolved external symbol _IsCharLowerA#4
LINK : error LNK2001: unresolved external symbol _WinMainCRTStartup
kod.exe : fatal error LNK1120: 6 unresolved externals
I have a code error LNK2001: unresolved external symbol _MessageBox (uploaded #2 "Final working code") is not succeed linking too

Answer 1

The problems was:
1) For scanf needed OFFSET scan_res, because not value is needed.
2) Can not be compiled using both windows and console subsystem. That's why i used only printfs.
3) Was not enough library msvcrt.
4) Сonverting from OMF to COFF could be ignored.
Working code:
.586
.model flat, stdcall
option casemap: none
include C:\masm32\include\windows.inc
include C:\masm32\include\user32.inc
include C:\masm32\include\msvcrt.inc
includelib C:\masm32\lib\msvcrt.lib
includelib C:\masm32\lib\user32.lib
.data
msg db 'Enter char: ', 0
result_0 db ' NOT LOWERCASE ', 0
result_1 db ' LOWERCASE ', 0
scan_modifier db '%c', 0
.data?
scan_res dd ?
.code
start:
mov ebp, esp
invoke crt_printf, OFFSET msg
invoke crt_scanf, OFFSET scan_modifier, OFFSET scan_res
push scan_res
call IsCharLowerA
cmp eax, 0
jne notNULL
invoke crt_printf, OFFSET result_0
jmp next
notNULL:
invoke crt_printf, OFFSET result_1
next:
ret
end start