mechanism_arg

    OpenVMS usage:mechanism vector address
    type:         quadword (unsigned)
    access:       read only
    mechanism:    by value
    The address of the location of the mechanism vector. If the
    mechanism_arg argument is 0, the mechanism vector for the
    currently active signal is used.

    If the address of the return_type argument is 0, the return_
    value argument is fetched by value and is treated as return-type
    PSIG$K_FR_U32. This combination of arguments can be used to set a
    condition code, such as SS$_ACCVIO, as a return value.

 return_type

    OpenVMS usage:integer
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    The address of the location of a longword that contains one of
    the function return signature codes.

    If the address of the return_type argument is 0, the return_
    value argument is fetched by value and is treated as return-type
    PSIG$K_FR_U32. This combination of arguments can be used to set a
    condition code, such as SS$_ACCVIO, as a return value.

 return_value

    OpenVMS usage:buffer
    type:         scalar
    access:       read only
    mechanism:    by reference
    The address of the location that contains a value of the
    appropriate type. The referenced value is read as a longword,
    quadword, or octaword, depending on the return_type.

    If the address of the return_type argument is 0, the return_
    value argument is fetched by value and is treated as return-type
    PSIG$K_FR_U32. This combination of arguments can be used to set a
    condition code, such as SS$_ACCVIO, as a return value.