Fatal errors stop execution and are numbered 1xxx.This appendix lists MASM 6.0 error and warning messages. Each message includes an explanation of what went wrong and what action to take to correct the problem.
Error numbers consist of a one- or two-letter prefix and four digits. The first digit indicates a severity level:
Fatal errors stop execution and are numbered 1xxx.
Errors numbered 2xxx are usually nonfatal; execution continues if possible.
Warnings do not stop execution but indicate a possible problem; they are numbered 4xxx.
Error messages may also display the input file and line number where the error occurred.