package fmt
State represents the printer state passed to custom formatters. It provides access to the io.Writer interface plus information about the flags and options for the operand's format specifier.
Golang fmt.State type usage examples
Example 1:
var s fmt.State
sign := ""
switch {
case s.Flag('+'):
sign = "+"
case s.Flag(' '):
sign = " "
}
Example 2:
func writeMany(text string, st fmt.State, counter int) {
if len(text) > 0 {
b := []byte(text)
for ; counter > 0; counter-- {
st.Write(b)
}
}
}
Example 3:
var f fmt.State
var s string
if w, ok := f.Width(); ok {
s += fmt.Sprintf("%d", w)
}
Reference :
http://golang.org/pkg/fmt/#State
