Converts a long integer to a character string.
    This function is OpenVMS Alpha and Integrity servers only.
    Format
      #include  <stdlib.h>
      char *l64a  (long l);
1 – Argument
 l
    A long integer that is to be converted to a character string.
2 – Description
    The a64l and l64a functions are used to maintain numbers stored
    in base-64 ASCII characters:
    o  a64l converts a character string to a long integer.
    o  l64a converts a long integer to a character string.
    Each character used to store a long integer represents a numeric
    value from 0 through 63. Up to six characters can be used to
    represent a long integer.
    The characters are translated as follows:
    o  A period (.)  represents 0.
    o  A slash (/)  represents 1.
    o  The numbers 0 through 9 represent 2 through 11.
    o  Uppercase letters A through Z represent 12 through 37.
    o  Lowercase letters a through z represent 38 through 63.
    The l64a function takes a long integer and returns a pointer to a
    corresponding base-64 notation of the least significant 32 bits.
    The value returned by l64a is a pointer to a thread-specific
    buffer whose contents are overwritten on subsequent calls from
    the same
    See also a64l.
3 – Return Value
    x                  Upon successful completion, a pointer to
                       the corresponding base-64 ASCII character-
                       string notation. If the l parameter is 0, l64a
                       returns a pointer to an empty string.