Visible to Intel only — GUID: GUID-473B6A20-076F-4870-9AB9-82D7D04E62BC
Visible to Intel only — GUID: GUID-473B6A20-076F-4870-9AB9-82D7D04E62BC
ATTRIBUTES REFERENCE and VALUE
The ATTRIBUTES directive options REFERENCE and VALUE specify how a dummy argument is to be passed.
!DIR$ ATTRIBUTES REFERENCE :: arg
!DIR$ ATTRIBUTES VALUE :: arg
arg |
Is the name of a dummy argument. |
REFERENCE specifies a dummy argument's memory location is to be passed instead of the argument's value.
VALUE specifies a dummy argument's value is to be passed instead of the argument's memory location.
When VALUE is specified for a dummy argument, the actual argument passed to it can be of a different type. If necessary, type conversion is performed before the subprogram is called.
When a complex (KIND=4 or KIND=8) argument is passed by value, two floating-point arguments (one containing the real part, the other containing the imaginary part) are passed by immediate value.
Character values, substrings, assumed-size arrays, and adjustable arrays cannot be passed by value.
If REFERENCE (only) is specified for a character argument, the string is passed with no length.
If REFERENCE is specified for a character argument, and C (or STDCALL) has been specified for the routine, the string is passed with no length. This is true even if REFERENCE is also specified for the routine.
If REFERENCE and C (or STDCALL) are specified for a routine, but REFERENCE has not been specified for the argument, the string is passed with the length.
VALUE is the default if the C or STDCALL option is specified in the subprogram definition.
In the following example integer x is passed by value:
SUBROUTINE Subr (x)
INTEGER x
!DIR$ ATTRIBUTES VALUE :: x
See Also
Mixed Language Programming: Adjusting Calling Conventions in Mixed-Language Programming Overview