One of the first modification done in Asmc (from jwasm) was the handling of file names from the command line. Jwasm expanded the full path of the argument, Asmc preserved the original name given by the user.
The reasoning for this was the 16-bit short/long filename conflict. These tools was feed the short version of the name and it was importen then to use the short name in the object file as well.
This means that the file name is taken more or less as given, and that includes quotes as well apparently. Same problem with -I".." and command line arguments in general.
"test".asm
Asmc Macro Assembler Version 2.23H
Portions Copyright (c) 1992-2002 Sybase, Inc. All Rights Reserved.
Assembling: test
ASMC : fatal error A1000: cannot open file : test
ASMC : fatal error A1000: cannot open file : .asm
HJWasm v2.23, Mar 31 2017, Masm-compatible assembler.
Portions Copyright (c) 1992-2002 Sybase, Inc. All Rights Reserved.
Source code is available under the Sybase Open Watcom Public License.
byte: 1
word: 1
dword: 1
qword: 1
test.asm: 19 lines, 2 passes, 0 ms, 0 warnings, 0 errors
asmc\"test".asm
ASMC : fatal error A1000: cannot open file : asmc\"test".asm
HJWasm:
Error A2106: Cannot open file: "asmc"test.asm" [ENOENT]
asmc\\"test".asm
ASMC : fatal error A1000: cannot open file : asmc\\"test".asm
HJWasm:
byte: 1
word: 1
dword: 1
qword: 1
asmc\test.asm: 19 lines, 2 passes, 10 ms, 0 warnings, 0 errors