8 # Usage
390 	// Usage is the function called when an error occurs while parsing flags.
392 	// a custom error handler. What happens after Usage is called depends
394 	// to ExitOnError, which exits the program after calling Usage.
395 	Usage func()  member
410 	Usage    string // help message  member
412 	DefValue string // default value (as text); for usage message
429 // Output returns the destination for usage and error messages. [os.Stderr] is returned if
448 // SetOutput sets the destination for usage and error messages.
550 	// usage message from being printed, but that we should report to the
563 // UnquoteUsage extracts a back-quoted name from the usage
564 // string for a flag and returns it and the un-quoted usage.
568 func UnquoteUsage(flag *Flag) (name string, usage string) {
570 	usage = flag.Usage
571 	for i := 0; i < len(usage); i++ {
572 		if usage[i] == '`' {
573 			for j := i + 1; j < len(usage); j++ {
574 				if usage[j] == '`' {
575 					name = usage[i+1 : j]
576 					usage = usage[:i] + name + usage[j+1:]
577 					return name, usage
612 		name, usage := UnquoteUsage(flag)
618 		// treat them specially, putting their usage on the same line.
626 		b.WriteString(strings.ReplaceAll(usage, "\n", "\n    \t"))
654 // a usage message showing the default settings of all defined
659 //		usage-message-for-x (default 7)
661 // The usage message will appear on a separate line for anything but
663 // omitted and if the flag name is one byte the usage message appears
666 // can be changed by placing a back-quoted name in the flag's usage
683 // defaultUsage is the default function to print a usage message.
686 		fmt.Fprintf(f.Output(), "Usage:\n")
688 		fmt.Fprintf(f.Output(), "Usage of %s:\n", f.name)
693 // NOTE: Usage is not just defaultUsage(CommandLine)
694 // because it serves (via godoc flag Usage) as the example
695 // for how to write your own usage function.
697 // Usage prints a usage message documenting all defined command-line flags
703 // Custom usage functions may choose to exit the program; by default exiting
706 var Usage = func() {  var
707 	fmt.Fprintf(CommandLine.Output(), "Usage of %s:\n", os.Args[0])
746 // BoolVar defines a bool flag with specified name, default value, and usage string.
748 func (f *FlagSet) BoolVar(p *bool, name string, value bool, usage string) {
749 	f.Var(newBoolValue(value, p), name, usage)
752 // BoolVar defines a bool flag with specified name, default value, and usage string.
754 func BoolVar(p *bool, name string, value bool, usage string) {
755 	CommandLine.Var(newBoolValue(value, p), name, usage)
758 // Bool defines a bool flag with specified name, default value, and usage string.
760 func (f *FlagSet) Bool(name string, value bool, usage string) *bool {
762 	f.BoolVar(p, name, value, usage)
766 // Bool defines a bool flag with specified name, default value, and usage string.
768 func Bool(name string, value bool, usage string) *bool {
769 	return CommandLine.Bool(name, value, usage)
772 // IntVar defines an int flag with specified name, default value, and usage string.
774 func (f *FlagSet) IntVar(p *int, name string, value int, usage string) {
775 	f.Var(newIntValue(value, p), name, usage)
778 // IntVar defines an int flag with specified name, default value, and usage string.
780 func IntVar(p *int, name string, value int, usage string) {
781 	CommandLine.Var(newIntValue(value, p), name, usage)
784 // Int defines an int flag with specified name, default value, and usage string.
786 func (f *FlagSet) Int(name string, value int, usage string) *int {
788 	f.IntVar(p, name, value, usage)
792 // Int defines an int flag with specified name, default value, and usage string.
794 func Int(name string, value int, usage string) *int {
795 	return CommandLine.Int(name, value, usage)
798 // Int64Var defines an int64 flag with specified name, default value, and usage string.
800 func (f *FlagSet) Int64Var(p *int64, name string, value int64, usage string) {
801 	f.Var(newInt64Value(value, p), name, usage)
804 // Int64Var defines an int64 flag with specified name, default value, and usage string.
806 func Int64Var(p *int64, name string, value int64, usage string) {
807 	CommandLine.Var(newInt64Value(value, p), name, usage)
810 // Int64 defines an int64 flag with specified name, default value, and usage string.
812 func (f *FlagSet) Int64(name string, value int64, usage string) *int64 {
814 	f.Int64Var(p, name, value, usage)
818 // Int64 defines an int64 flag with specified name, default value, and usage string.
820 func Int64(name string, value int64, usage string) *int64 {
821 	return CommandLine.Int64(name, value, usage)
824 // UintVar defines a uint flag with specified name, default value, and usage string.
826 func (f *FlagSet) UintVar(p *uint, name string, value uint, usage string) {
827 	f.Var(newUintValue(value, p), name, usage)
830 // UintVar defines a uint flag with specified name, default value, and usage string.
832 func UintVar(p *uint, name string, value uint, usage string) {
833 	CommandLine.Var(newUintValue(value, p), name, usage)
836 // Uint defines a uint flag with specified name, default value, and usage string.
838 func (f *FlagSet) Uint(name string, value uint, usage string) *uint {
840 	f.UintVar(p, name, value, usage)
844 // Uint defines a uint flag with specified name, default value, and usage string.
846 func Uint(name string, value uint, usage string) *uint {
847 	return CommandLine.Uint(name, value, usage)
850 // Uint64Var defines a uint64 flag with specified name, default value, and usage string.
852 func (f *FlagSet) Uint64Var(p *uint64, name string, value uint64, usage string) {
853 	f.Var(newUint64Value(value, p), name, usage)
856 // Uint64Var defines a uint64 flag with specified name, default value, and usage string.
858 func Uint64Var(p *uint64, name string, value uint64, usage string) {
859 	CommandLine.Var(newUint64Value(value, p), name, usage)
862 // Uint64 defines a uint64 flag with specified name, default value, and usage string.
864 func (f *FlagSet) Uint64(name string, value uint64, usage string) *uint64 {
866 	f.Uint64Var(p, name, value, usage)
870 // Uint64 defines a uint64 flag with specified name, default value, and usage string.
872 func Uint64(name string, value uint64, usage string) *uint64 {
873 	return CommandLine.Uint64(name, value, usage)
876 // StringVar defines a string flag with specified name, default value, and usage string.
878 func (f *FlagSet) StringVar(p *string, name string, value string, usage string) {
879 	f.Var(newStringValue(value, p), name, usage)
882 // StringVar defines a string flag with specified name, default value, and usage string.
884 func StringVar(p *string, name string, value string, usage string) {
885 	CommandLine.Var(newStringValue(value, p), name, usage)
888 // String defines a string flag with specified name, default value, and usage string.
890 func (f *FlagSet) String(name string, value string, usage string) *string {
892 	f.StringVar(p, name, value, usage)
896 // String defines a string flag with specified name, default value, and usage string.
898 func String(name string, value string, usage string) *string {
899 	return CommandLine.String(name, value, usage)
902 // Float64Var defines a float64 flag with specified name, default value, and usage string.
904 func (f *FlagSet) Float64Var(p *float64, name string, value float64, usage string) {
905 	f.Var(newFloat64Value(value, p), name, usage)
908 // Float64Var defines a float64 flag with specified name, default value, and usage string.
910 func Float64Var(p *float64, name string, value float64, usage string) {
911 	CommandLine.Var(newFloat64Value(value, p), name, usage)
914 // Float64 defines a float64 flag with specified name, default value, and usage string.
916 func (f *FlagSet) Float64(name string, value float64, usage string) *float64 {
918 	f.Float64Var(p, name, value, usage)
922 // Float64 defines a float64 flag with specified name, default value, and usage string.
924 func Float64(name string, value float64, usage string) *float64 {
925 	return CommandLine.Float64(name, value, usage)
928 // DurationVar defines a time.Duration flag with specified name, default value, and usage string.
931 func (f *FlagSet) DurationVar(p *time.Duration, name string, value time.Duration, usage string) {
932 	f.Var(newDurationValue(value, p), name, usage)
935 // DurationVar defines a time.Duration flag with specified name, default value, and usage string.
938 func DurationVar(p *time.Duration, name string, value time.Duration, usage string) {
939 	CommandLine.Var(newDurationValue(value, p), name, usage)
942 // Duration defines a time.Duration flag with specified name, default value, and usage string.
945 func (f *FlagSet) Duration(name string, value time.Duration, usage string) *time.Duration {
947 	f.DurationVar(p, name, value, usage)
951 // Duration defines a time.Duration flag with specified name, default value, and usage string.
954 func Duration(name string, value time.Duration, usage string) *time.Duration {
955 	return CommandLine.Duration(name, value, usage)
958 // TextVar defines a flag with a specified name, default value, and usage string.
963 …Set) TextVar(p encoding.TextUnmarshaler, name string, value encoding.TextMarshaler, usage string) {
964 	f.Var(newTextValue(value, p), name, usage)
967 // TextVar defines a flag with a specified name, default value, and usage string.
972 func TextVar(p encoding.TextUnmarshaler, name string, value encoding.TextMarshaler, usage string) {
973 	CommandLine.Var(newTextValue(value, p), name, usage)
976 // Func defines a flag with the specified name and usage string.
979 func (f *FlagSet) Func(name, usage string, fn func(string) error) {
980 	f.Var(funcValue(fn), name, usage)
983 // Func defines a flag with the specified name and usage string.
986 func Func(name, usage string, fn func(string) error) {
987 	CommandLine.Func(name, usage, fn)
990 // BoolFunc defines a flag with the specified name and usage string without requiring values.
993 func (f *FlagSet) BoolFunc(name, usage string, fn func(string) error) {
994 	f.Var(boolFuncValue(fn), name, usage)
997 // BoolFunc defines a flag with the specified name and usage string without requiring values.
1000 func BoolFunc(name, usage string, fn func(string) error) {
1001 	CommandLine.BoolFunc(name, usage, fn)
1004 // Var defines a flag with the specified name and usage string. The type and
1010 func (f *FlagSet) Var(value Value, name string, usage string) {
1019 	flag := &Flag{name, usage, value, value.String()}
1039 // Var defines a flag with the specified name and usage string. The type and
1045 func Var(value Value, name string, usage string) {
1046 	CommandLine.Var(value, name, usage)
1056 // failf prints to standard error a formatted error and usage message and
1060 	f.usage()
1064 // usage calls the Usage method for the flag set if one is specified,
1065 // or the appropriate default usage function otherwise.
1066 func (f *FlagSet) usage() {  func
1067 	if f.Usage == nil {
1070 		f.Usage()
1112 			f.usage()
1202 	// Override generic FlagSet default Usage with call to global Usage.
1203 	// Note: This is not CommandLine.Usage = Usage,
1204 	// because we want any eventual call to use any updated value of Usage,
1206 	CommandLine.Usage = commandLineUsage
1210 	Usage()
1215 // in the default usage message and in error messages.
1221 	f.Usage = f.defaultUsage