source-string

    OpenVMS usage:char_string
    type:         character string
    access:       read only
    mechanism:    by descriptor

    Source string to be copied to the common area by LIB$PUT_COMMON.
    The source-string argument is the address of a descriptor
    pointing to this source string.

 resultant-length

    OpenVMS usage:word_unsigned
    type:         word (unsigned)
    access:       write only
    mechanism:    by reference

    Number of characters copied by LIB$PUT_COMMON to the common area.
    The resultant-length argument is the address of an unsigned word
    integer that contains this number of characters. LIB$PUT_COMMON
    writes this number into the resultant-length argument.