Documentation of warning/error output.

[Harvey Chapman <hchapman-gcc-help@xxxxxxxx>]

Is there any documentation of warning/error output. I couldn't find any 
mention of either in the gcc or cpp manuals.

Specifically, I'm looking for documentation of the following along with 
perhaps the other lines that get output with warnings. What is the 3rd 
field, ":2:"?

<stdin>:1:2: warning: #warning Blah
<stdin>:2:2: error: #error Joe

Thanks,

Harvey