It would be very helpful if you could post your code examples using code tags, [code ][/code ], there is a space before the ] that you don't actually put in, but I have added it so you could read the tag text.

Here is an example,

Code:

DO i=1,numfiles
  tmp = trim(basefile)
  WRITE(tmp(LEN_TRIM(tmp)+1:LEN_TRIM(tmp)+4),33) i
  OPEN(unit=10+i, file=tmp, status='old' iostat=ios)
  IF ( ios /= 0 ) THEN
    PRINT *,'Unable to open',TRIM(tmp)
  ELSE
    IF(verbose) PRINT *,TRIM(tmp),' opened   succesfully'
  ENDIF
ENDDO

C All the files are closed at the end of the program as

CLOSE ( unit = 10 );
DO i=1,numfiles
  CLOSE (unit=10+i)
ENDDO

I still program in fortran 77, so this syntax is not clear to me. I would set up a do loop with a control line number and not an ENDDO. I would also evaluate with .NE. instead of /=. etc.

The thing to do is to create a small program that just opens your files, closes your files, and prints something to confirm success. Get that to work. You can post that here with a sample input file so others can test it.

Most likely, you are exceeding the capacity of some data structure that stores the contents of the files, but that is hard to know without seeing the declarations. After you get the files opening and closing, you can look at the data structures in the program and add what is necessary to store the data. It can be helpful to have apps like this process one input file at a time if that is possible. Then it shouldn't matter how many input files you process, only how large the largest file is.

Fortran doesn't have dynamic memory allocation, so you have to pre-size your data structures to be larger than needed and also trap out the data loading process so you can quit with a handled exception if your data is larger than the available space. If that is a huge issue, you may consider re-writing some of the subroutines in c++, which has containers like vectors and maps that can re-size on the fly. It is generally not a problem to have mixed language code and calling a c++ function from Fortran code is not that difficult as long as you can compile both languages.

Fortran is a beastly language for file I/O and I'm sure it wold be very much easier to write this program in c++, or better yet, and interpreter like perl, python, or ruby. If the app is 500 lines of f95, it is probably 200 lines of c++, or 15 lines of python.

LMHmedchem