(errno)
This procedure returns the current value of errno as an exact integer.
The current value of errno is returned.
> (errno)
0
> (define p (open-input-file "unknown"))
ERROR!
message : cannot open file
irritant : #<primitive-procedure internal-open-input-file>
expression: fname
continue : possible, continue with value as value from primitive
Error (? for help) >>
> (errno)
2
>