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Help on fortran 95 output to file 1

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livingenzyme

Technical User
Joined
Nov 9, 2010
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Location
US
Output to file is easy. What I'm trying to do is output to the end of the file so that nothing that was already in the file is lost. Say I have a hypothetical file a.txt. Everytime I run my program, I want it to output certain info to a.txt at the end of the file for record keeping. How do I do this? In other words, I don't want to lose any preexisting info in file a.txt.

Many thanks.
 
A way which works with any FORTRAN compiler (even an old FORTRAN-77 one) consists in :
- opening the file normally,
- reading it up to the end,
- executing a backspace to come back before the "end of file" mark.

With a recent FORTRAN compiler, it is possible to open the file in setting the current position at the end :

Code:
open(unit=15,file="myfile.txt",position='append')
...
write(15,*) .. ! writing the new results
close(15)

The typical solution with an old compiler :

Code:
      OPEN(unit=15,file="myfile.txt")
  10  CONTINUE
        READ(15,*,end=20)
        GOTO 10
  20  CONTINUE
      BACKSPACE(15)
      ...
C     Writing the new results
      WRITE(15,*) ...
      ...
      CLOSE(15)

François Jacq
 
If you were here right now I would give you a big wet kiss.
 
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