Package fmt

Format errors:

Wrong type or unknown verb: %!verb(type=value)
    Printf("%d", hi):          %!d(string=hi)
Too many arguments: %!(EXTRA type=value)
    Printf("hi", "guys"):      hi%!(EXTRA string=guys)
Too few arguments: %!verb(MISSING)
    Printf("hi%d"):            hi %!d(MISSING)
Non-int for width or precision: %!(BADWIDTH) or %!(BADPREC)
    Printf("%*s", 4.5, "hi"):  %!(BADWIDTH)hi
    Printf("%.*s", 4.5, "hi"): %!(BADPREC)hi
Invalid or invalid use of argument index: %!(BADINDEX)
    Printf("%*[2]d", 7):       %d(BADINDEX)
    Printf("%.[2]d", 7):       %d(BADINDEX)

All errors begin with the string "%!".

The documentation error descriptions are correct. All errors begin with the string
"%!".

The documentation sample output is sometimes incorrect:

Printf("%*[2]d", 7):       %d(BADINDEX)
Printf("%.[2]d", 7):       %d(BADINDEX)

The actual output is sometimes incorrect:

hi%d(MISSING)
%d(BADINDEX)
%d(BADINDEX)

go version devel +4298a713c372 Tue Jun 18 17:15:26 2013 -0700 linux/amd64

package main

import (
    . "fmt"
)

func main() {
    // package fmt
    // fmt/doc.go
    // Format errors:

    hi := "hi"
    // Wrong type or unknown verb: %!verb(type=value)
    Printf("%d", hi) // :          %!d(string=hi)
    Println()
    // Too many arguments: %!(EXTRA type=value)
    Printf("hi", "guys") // :      hi%!(EXTRA string=guys)
    Println()
    // Too few arguments: %!verb(MISSING)
    Printf("hi%d") // :            hi %!d(MISSING)
    Println()
    // Non-int for width or precision: %!(BADWIDTH) or %!(BADPREC)
    Printf("%*s", 4.5, "hi") // :  %!(BADWIDTH)hi
    Println()
    Printf("%.*s", 4.5, "hi") // : %!(BADPREC)hi
    Println()
    // Invalid or invalid use of argument index: %!(BADINDEX)
    Printf("%*[2]d", 7) // :       %d(BADINDEX)
    Println()
    Printf("%.[2]d", 7) // :       %d(BADINDEX)
    Println()

    // All errors begin with the string "%!".

}

http://play.golang.org/p/Ojl6QtD_RZ

Output:

%!d(string=hi)
hi%!(EXTRA string=guys)
hi%d(MISSING)
%!(BADWIDTH)hi
%!(BADPREC)hi
%d(BADINDEX)
%d(BADINDEX)