VMS Help RTL Routines, LIB$, LIB$SCANC, Returns  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    OpenVMS usage:cond_value
    type:         longword (unsigned)
    access:       write only
    mechanism:    by value

    Relative position in the source string of the character that
    terminated the operation, or zero if the terminator character is
    not found. If the source string has a zero length, then a zero is
    returned.