A dummy argument with the INTENT(IN) attribute shall not appear in a variable definition context

[milenko1976]

Why is this illegal?

module modelpet

implicit none

contains
subroutine rm(xn,res,icd,ivar)
real,dimension(57,3),intent(in) :: xn
real,dimension(57) :: a,b,c
real,dimension(57),intent(out) :: res,icd,ivar
xn(:,1)=a
a=res
xn(:,2)=b
b=icd
xn(:,3)=c
c=ivar

end subroutine
end module
milenko@milenkons:~/ircg$ ifort -c modelpet.for
modelpet.for(10): error #6780: A dummy argument with the INTENT(IN) attribute shall not appear in a variable definition context [XN]
xn(:,1)=a
------^
modelpet.for(12): error #6780: A dummy argument with the INTENT(IN) attribute shall not appear in a variable definition context [XN]
xn(:,2)=b
------^
modelpet.for(14): error #6780: A dummy argument with the INTENT(IN) attribute shall not appear in a variable definition context [XN]
xn(:,3)=c
------^
modelpet.for(6): warning #6843: A dummy argument with an explicit INTENT(OUT) declaration is not given an explicit value. [RES]
subroutine rm(xn,res,icd,ivar)
-----------------------^
modelpet.for(6): warning #6843: A dummy argument with an explicit INTENT(OUT) declaration is not given an explicit value. [ICD]
subroutine rm(xn,res,icd,ivar)
---------------------------^
modelpet.for(6): warning #6843: A dummy argument with an explicit INTENT(OUT) declaration is not given an explicit value. [IVAR]
subroutine rm(xn,res,icd,ivar)
-------------------------------^
compilation aborted for modelpet.for (code 1)

[Steven_L_Intel1]

Perhaps you misunderstand the meaning of the INTENT attribute? With INTENT(IN), you are promising to the compiler that argument XN is not modified nor its definition status changed, but you assign to it. This is an error the compiler is required to detect.

Similarly, INTENT(OUT) says that variables res, icd and var are always assigned a value in the routine, but yoiu don't do so, Again, the compiler detects this.

Does this help?

[milenko1976]

Yes, I have to do it other way
Thanks.

[Steven_L_Intel1]

What do you want to do?

[TimP]

I've found the compiler's diagnostics for INTENT extremely useful in building a full list of argument usage.