How to copy a file in Fortran 90?

Question

How can I copy a file in fortran 90 in a portable, cross plaform way ?

Solution

You can read/write the file through a stream in Fortran 2003, but in Fortran 90/95 I think this would work to copy an arbitrary file (extremely inefficient though!!)

OPEN(UNIT=ISRC, FILE='', ACCESS='DIRECT', STATUS='OLD', ACTION='READ', IOSTAT=IERR, RECL=1)
OPEN(UNIT=IDST, FILE='', ACCESS='DIRECT', STATUS='REPLACE', ACTION='WRITE', IOSTATE=IERR, RE)
IREC = 1
DO
  READ(UNIT=ISRC, REC=IREC, IOSTAT=IERR) CHAR
  IF (IERR.NE.0) EXIT
  WRITE(UNIT=IDST, REC=I) CHAR
  IREC = IREC + 1
END DO

Of course, if it was a fortran generated file, you could use that information to make it more efficient.

On a personal note: if you need invoke system calls from inside fortran, what are you doing? Isn't it better to use some other language that is better suited for the task?