Treats warnings as errors.
Any messages that would ordinarily be reported as warnings are instead reported as errors. No output files are created. The build continues in order to identify as many errors/warnings as possible.
By default, /warnaserror- is in effect, which causes warnings to not prevent the generation of an output file. /warnaserror, which is the same as /warnaserror+, causes warnings to be treated as errors.
Use /warn to specify the level of warnings that you want the compiler to display.