w, W

Specifies the level of diagnostic messages to be generated by the compiler.

Syntax

Linux:

-wn

Windows:

/Wn

n

Is the level of diagnostic messages to be generated. Possible values are:

0	Enables diagnostics for errors. Disables diagnostics for warnings.
1	Enables diagnostics for warnings and errors.
2	Enables diagnostics for warnings and errors. On Linux* systems, additional warnings are enabled. On Windows* systems, this setting is equivalent to level 1 (`n`= 1).
3	Enables diagnostics for remarks, warnings, and errors. Additional warnings are also enabled above level 2 (`n` = 2). This level is recommended for production purposes.
4	Enables diagnostics for all level 3 (`n` = 3) warnings plus informational warnings and remarks, which in most cases can be safely ignored. This value is only available on Windows* systems.
5	Enables diagnostics for all remarks, warnings, and errors. This setting produces the most diagnostic messages. This value is only available on Windows* systems.

n=1	The compiler displays diagnostics for warnings and errors.

This option specifies the level of diagnostic messages to be generated by the compiler.

On Windows systems, option /W4 is equivalent to option /Wall.

The -wn, /Wn, and Wall options can override each other. The last option specified on the command line takes precedence.

Visual Studio: General > Warning Level

Eclipse: General > Warning Level

None