flag.Bool() Function in Golang With Examples
Go language provides inbuilt support for command-line parsing and has functions that could be used to define flags to be used with a command-line program using the flag
package. This package provides the flag.Bool() function which is used to define a boolean flag with the specified name, default value, and usage string.
Syntax:
func Bool(name string, value bool, usage string) *bool
Parameters: This function accepts three parameters as mentioned above and described below:
- name: It is a string that specifies the name to be used for the flag.
- value: It is a boolean value that specifies the default value to be used by the flag.
- usage: It is a string that specifies the usage or help message to be shown for the flag.
Return Value: It returns an address of the boolean variable that stores the value of the flag defined.
Below programs illustrate the flag.Bool() function:
Example 1:
package main
import (
"flag"
"fmt"
)
func main() {
boolArgPtr := flag.Bool( "arg1" , false , "This is a bool argument" )
flag.Parse()
fmt.Println( "Bool Arg:" , *boolArgPtr)
}
|
Output:
Example 2:
package main
import (
"flag"
"fmt"
)
func main() {
plainArgPtr := flag.Bool( "plaintext" , false , "Enable plaintext" )
jsonArgPtr := flag.Bool( "json" , false , "Enable JSON" )
csvArgPtr := flag.Bool( "csv" , false , "Enable CSV" )
flag.Parse()
fmt.Println( "Enable plaintext:" , *plainArgPtr)
fmt.Println( "Enable JSON:" , *jsonArgPtr)
fmt.Println( "Enable CSV:" , *csvArgPtr)
}
|
Output
Last Updated :
19 May, 2020
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