verify(3I)

NAME
     VERIFY - Verifies that a set of characters contains all characters in
     a string

SYNOPSIS
     VERIFY ([STRING=]string, [SET=]set [,[BACK=]back])

STANDARDS
     Fortran

DESCRIPTION
     The VERIFY intrinsic function verifies that a set of characters
     contains all characters in a string by identifying the first character
     position in a string of characters that does not appear in a given set
     of characters.  VERIFY accepts the following arguments:

     string    Must be of type character variable.

     set       Must be of type character variable, expression, or constant.

     back      Must be of type logical.  If back is omitted, a value of
               false is assumed.

     VERIFY is an elemental function.  The name of this intrinsic cannot be
     passed as an argument.

RETURN VALUES
     The result is an integer.

     If back is absent or is present with a value FALSE and string contains
     at least one character that is not in set, the value of the result is
     the position of the leftmost character of string that is not in set.

     If back is present with a value TRUE and if string contains at least
     one character that is not in set, the value of the result is the
     position of the rightmost character of string that is not in set.

     VERIFY returns 0 if each character in string is in set, or if the
     length of string is 0.

EXAMPLES
     VERIFY('ABBA','A') yields 2.

     VERIFY('ABBA','A',BACK=.TRUE.) yields 3.

     VERIFY('ABBA','AB') yields 0.