The required argument consists of whatever follows immediately within the same command-line token, else is the whole of the next command-line token if this token does not begin with a hyphen or forward slash.

The argument is formally numeric. Values greater than 4 are coerced to 1, with a warning (D4014).


The /W option overrides earlier instances of itself (and is overridden by later instances). A first instance, /W1, is provided by CL as an initial option.


This option passes to both the front-end and back-end compilers (C1, C1XX and C2).