why I cannot write(stdout) in subroutine

[DongYe]

I want write(stdout,*) in subroutine step3d_uv.F,however ,when I make ,it said 'Error: Symbol 'stdout' at (1) has no IMPLICIT type'.
however,I find many 'write(stdout)' in other subroutines ,why here it doesn't work ,
when I try it in main3d.F,it is work.
so I am confused.

[kate]

I suggest you visit a Fortran 90 tutorial online (or elsewhere) and read up on the scope of variables and Fortran 90 modules.