forums.silverfrost.com

[Magliola]

Does Silverfrost FTN95 allow statements such as

print *, ' This is a test '

and

write(*, 100)
100 format(1x,' This is a test')


Sometimes print * and write (*, ) works and sometimes I get the following error at run time:

*** Error 94, Unit has neither been OPENed nor preconnected

Also I cannot find where print * and write (*, ) are documented in Silverfrost FTN95 documentation.

(I am porting over code from a compiler where the above statements are valid.)

Thanks to anybody that helps with this.
_________________
Regards,
Bob

[JohnCampbell]

You should not get the error report you have identified for the code examples you have provided.
I typically use write (*,*) 'This is a test'

where you would probably get the error report is when you have:
write (1,*) 'This is a test'
or
write (6,*) 'This is a test'
In these cases, the code was written where fortran unit 1 or 6 defaulted to standard output. Salford Fortran defaults unit 1, although 5 and 6 also work. This might not be the case with other compilers. The following example demonstrates what works with FTN95.

[Magliola]

John,
Thank you for the help and post. I ran your bit of code and I get the following:

successful test for unit 1
successful test for unit 2
ERROR : unsuccessful test for unit 3
ERROR : unsuccessful test for unit 4
successful test for unit 5
successful test for unit 6
ERROR : unsuccessful test for unit 7
ERROR : unsuccessful test for unit 8
ERROR : unsuccessful test for unit 9
ERROR : unsuccessful test for unit 10

It looks like units 1, 2, 5 and 6 all default to output to the console window.

I did a little testing and I see that if units 1 through 10 are all first assigned to files then write(*,*) and print * both write to the file attached to unit 2. So * and 2 are synonymous.

Is there a default unit for reading from the keyboard?

I am writing short test programs to try replicating the error in the ported program. But no luck so far. (i.e. I cannot duplicate the error.)

Any ideas why print * and write (*, *) works and sometimes I get the following error at run time:

*** Error 94, Unit has neither been OPENed nor preconnected

It looks like error 94 should never happen with print * and write (*, *).
_________________
Regards,
Bob

[PaulLaidler]

Units 1,2,5 and 6 are reserved for standard input and output.

[Magliola]

Thank you John and thank you Paul for helping me solve this code problem.

For reference, the symptoms the code had and the error are thus:
1) WRITE (*,*) works as expected with output to the console window.
2) the code then opens unit 2 as a scratch file.
3) WRITE (*,*) now writes to the scratch file. [That explains why the write (*,*) stopped writing to the console window.]
4) the code then executes CLOSE(2,STATUS='KEEP'). The next occurrence of WRITE (*,*) crashes the program with the Error 94.

Follow up Question:
In good practice how should one take advantage of units 1,2,5 and 6 in their code?
_________________
Regards,
Bob

[JohnCampbell]

My approach to good practice is to never open a file using a file unit number less than 11. (11 for read, 12 for write) This copes with all fortran compilers I have ever used.
I typically open text files for units 11-19, binary files on 21+ and a log file on unit 98. This approach has been based on once using a compiler that limited the file number to 99.
I am not sure what the maximum number can be, but I have seen examples of unit numbers 1000+. I have never realy had to find out.
Over the years, there have been many posts where people got in trouble with "reserved" file unit numbers < 10. I did know that units 1,5 and 6 were often special but have never had the need to find out that unit 2 is also reserved in FTN95. There's always somenthig new.

John

[Magliola]

John, Thank you for your help and advice. I am definitely adopting your practice to unit numbering.
_________________
Regards,
Bob