This function is used to examine an argument supplied as a string and returns its numeric value. If the string supplied begins with a leading 0, it is treated as an octal number. If the string begins with a leading 0x, it is treated as a hexadecimal number. The following example illustrates the working strtonum() function:

$ vi strtonum.awk

BEGIN    {
    print "Decimal num strtonum(123)    : ", strtonum(123)
    print "Octal num strtonum(0123)     : ", strtonum(0123)
    print "Hexadecimal num strtonum(0x123)  : ", strtonum(0x123)
}

$ awk -f strtonum.awk

The output of the execution of the previous code is as follows:

Decimal num strtonum(123)    :  123
Octal num strtonum(0123)     :  83
Hexadecimal num strtonum(0x123)  :  291

Apart from the preceding function, we have asort (sring,[a]) and asorti(string, [a]), which are available only in GAWK and which we will ;discuss in Chapter 9, GNU's Implementation of AWK - GAWK (GNU AWK).