/Wn option specifies the level of warnings to be generated. n is a number from 0 to 4 or all with the following meaning: /W0: all warnings are disabled (apparently the same as the small cap /w)
/W1: severe warnings. This is the default
/W2: Additionally warn about siginificant findings
/W3: Warn about production quality impacts
/W4: Show informational warnings too
/Wall: Also include warnings that are not turned off by default /w… allows to modify warning levels, suppress warnings or treat warnins as errors. -W) #pragma warning(push) and #pragma warning(disable:…).