topic Re: fortran binary files in Intel® Fortran Compiler

fortran binary files

WSinc — Wed, 08 Jul 2020 07:55:52 GMT

I am under the impression I can make a binary file that allows random access to a set of fixed size records.

Its allowing me to write records sequentially, but if I pick a record number, I cant do that.

for example if I have 100 records of 20 integer words each, I should be able to pick and replace record number 48, right?

Maybe I dont have the right set of keywords to open the file. But you dont give us any examples that I can find.

Re: fortran binary files

WSinc — Wed, 08 Jul 2020 08:10:45 GMT

subroutine screwup
integer(4) pr(6000)
open(2,file='screwup2.dat',form='binary',recl=6000)
do 10 irec=1,100
10 write(2,rec=irec)pr
rewind 2
do 20 irec=1,100
read(2,rec=irec)pr
20 print *,"rec ",irec," read"
pause
end

As long as I write the files and read them sequentially, it works.

But I cannot pick a record randomly. So that rec=irec option illegal ?

Re: fortran binary files

mecej4 — Wed, 08 Jul 2020 09:45:51 GMT

Read about the ACCESS='DIRECT' specifier in the file OPEN statement. Related to this is he specifier FORM='...'

Do not use the nonstandard FORM='BINARY' unless you understand the implications.

Re: fortran binary files

WSinc — Wed, 08 Jul 2020 11:15:02 GMT

I have to say Form="binary" since I am working with Midi files,

generated by music software.

Anyway thanks for the helpful tips.

Re: fortran binary files

Steve_Lionel — Wed, 08 Jul 2020 17:24:16 GMT

form='binary' is an extension. Instead you should be using form="unformatted", access="stream".

Re: fortran binary files

WSinc — Wed, 08 Jul 2020 20:13:40 GMT

Well, I still cant get it to access that file, when I use your suggestion.

It says "file not found" even when the file is where it can easily find it.

So should I be able to attach the file, regardless of what kind it is ?

subroutine getmid()
character*20 FN/"LAFA.mid"/
integer(4) midirec(60)
!
110 format(A20)
12 open(2,file="LAFA.MID", &
form="unformatted", access="stream", action="READ")
do irec=1,100
read(2)midirec
print *,"record ",irec," read"
enddo
end

Didnt someone write about this matter recently ?

Re: fortran binary files

jimdempseyatthecove — Wed, 08 Jul 2020 20:59:10 GMT

>>It says "file not found" even when the file is where it can easily find it.

Then most likely the (your) current directory is not where you expect it to be.

The current directory can be located anywhere.

When launched from an IDE, the current directory is usually specified on some property page (e.g. Debug or Release configuration). Default for MS Visual Studio is the Project Folder, but you can set it anywhere else. Your executable is likely located elsewhere.

You could add an OPEN file for output such as "WhereAmI" write something to it (e.g. "Here I am"), close the file. Then find the file.

There is also a Current Drive.

Using "LAFA.MID" specifies the file is located in the "current directory" on the "current drive.

Function GETDRIVEQQ and GETDRIVEDIRQQ can also be used to query the system.

Jim Dempsey

Re: fortran binary files

andrew_4619 — Wed, 08 Jul 2020 21:24:52 GMT

Use the full path file name as a good low effort starting point!

Re: fortran binary files

WSinc — Fri, 10 Jul 2020 00:34:26 GMT

I made sure the executable is where where Its supposed to be,

By opening a scratch file and seeing where it gets put. I can verify that it is always put in the same location as the data I want to look at.

And I can always attach the file on an OPEN statement, but every time I try to read one record it gives me an EOF return, rather than reading in the data.

Is there someone at INTEL that has actually had to deal with a similar problem, so we dont do this endless guesswork ? I will pay for their time.

The file I am working with was probably generated on a MAC machine, which is why I have to treat it as a "strange" format, with a raw set of data bytes.

Re: fortran binary files

andrew_4619 — Fri, 10 Jul 2020 07:49:15 GMT

Can you share the file you are trying to read?

Re: fortran binary files

jimdempseyatthecove — Fri, 10 Jul 2020 14:28:49 GMT

>>And I can always attach the file on an OPEN statement, but every time I try to read one record it gives me an EOF return, rather than reading in the data.

Your original post was File Not Found. So now you have File Found, but data not being read.

It is likely that the data you have composed for consumption is not conformant with the READ statements you are issuing.

Fortran expects data format compatible with the format specified in the OPEN statement. For example of an erroneous condition, your Open expects textual data, perhaps comma delimited. Fortran expects (requires) the file to be ASCII (7-bit) compliant. Should you create your input file using say WordPad, the default output format is UTF-8, not 7-bit ASCII. To correct this in WordPad you use SaveAs and select Plain Text format.

You should be able to construct a simple program (e.g. with OPEN, READ a record, PRINT a record) and supply a small data file. (assuming the example program exhibits the error).

Jim Dempsey

Re: fortran binary files

Steve_Lionel — Fri, 10 Jul 2020 16:51:51 GMT

It is almost certainly the case that the program is opening the file in a different location than you expect. If you are running from inside Visual Studio, the default directory is the project directory, NOT the one with the EXE.

What will happen then is that the OPEN will create a new, empty file, which then gets you an EOF when you try to read from it. Look for other copies of this data file and you will likely find an empty one where you don't expect it.

This is a fairly common thing that Windows users run into. It has nothing to do with the data file itself.

Re: fortran binary files

WSinc — Fri, 10 Jul 2020 22:12:19 GMT

Actually, when I get an error message, I can always look at the path it took in the file directory.

I dont understand why I still sometime get "file not found" when the file directory is correct and the file is sitting there.

Re: fortran binary files

WSinc — Fri, 10 Jul 2020 22:18:05 GMT

It doesn't give give me a way to do that.

Not obvious, anyway. It is sitting in my user file directory,

but how do I transfer the whole file ?

This was imported from outside, but I find it hard to understand why there is no way to examine the contents of it, even as a "raw binary"

Would access="STREAM" be the correct way ?

Re: fortran binary files

WSinc — Fri, 10 Jul 2020 22:30:10 GMT

Here is the file I am trying to read.

I am trying to use "drag and drop." or Browse files.

But nothing happens when I click on that.

Dont they bother to check this stuff ?

Re: fortran binary files

Steve_Lionel — Fri, 10 Jul 2020 23:32:40 GMT

You can put the file in a ZIP archive and attach that. I am going to test that here. (It worked. Be sure to drag it onto the "attach" box and not the message box.)

Would you please show the actual and complete error message you get for "file not found" and also a directory listing of the directory you think the file should be found in? That you sometimes get EOF tells me that it is being created empty because the intended file is not there.

I do recommend using ACCESS='STREAM', FORM='UNFORMATTED' (and unformatted READs) to read binary data.

Re: fortran binary files

WSinc — Sat, 11 Jul 2020 00:08:28 GMT

input file name:
lafa.mid
Access method:
stream
LGU 2 file opened OK
forrtl: severe (24): end-of-file during read, unit 2, file C:\Users\Administrator\documents\visual studio 2010\Projects\Console8\Console8\lafa.mid
Image PC Routine Line Source
libifcoremdd.dll 510B19D2 Unknown Unknown Unknown
libifcoremdd.dll 510EED7F Unknown Unknown Unknown
Console8.exe 00C612A6 _GETMIDI 29 CONSOLE8.F90
Console8.exe 00C63F37 _MAIN__ 7 CONSOLE8.F90
Console8.exe 00C65CAF Unknown Unknown Unknown
Console8.exe 00C6466F Unknown Unknown Unknown
Console8.exe 00C6449F Unknown Unknown Unknown
KERNEL32.DLL 76B16359 Unknown Unknown Unknown
ntdll.dll 77467B74 Unknown Unknown Unknown
ntdll.dll 77467B44 Unknown Unknown Unknown

You can see that it attaches the file, but I get the ERROR QUIT when it tries to do any reading from it. I did use the Stream input method, as you recommended.

Re: fortran binary files

Steve_Lionel — Sat, 11 Jul 2020 00:39:49 GMT

We'd need to see a small test program that demonstrates the problem. It could be that your program is reading past the end of the file. Please attach ZIP of the file and a program we can look at. Ideally this would be a small program that just tries to read some data from the file, but if you can't make that work the whole program is ok.

Re: fortran binary files

WSinc — Sat, 11 Jul 2020 00:58:44 GMT

OK, here is the source code. I am trying to read a standard MIDI file from a music program.

subroutine getmidi()
character*20 FN
character*20 AM
integer(4) midirec(60)
!
110 format(A20)
12 print *,"input file name:"
READ(*,110)FN
print *,"Access method:"
READ(*,110)AM
open(2,file=FN,access=AM, form="UNFORMATTED")
35 print *,"LGU 2 file opened OK"
do irec=1,100
! this is where it falls apart
! It gives me an EOF, rather than reading in any data.
! I am trying to use STREAM input
read(2)midirec
print *,"record ",irec," read"
print *,"contents:",midirec
enddo
end

Re: fortran binary files

WSinc — Sat, 11 Jul 2020 01:12:27 GMT

BTW, the file I was reading has more than 230K bytes of data, so I dont think I would be getting an End-of-File right at the beginning of the 1st read operation. I had trouble attaching the actual file, but I can make a more concerted effort if needed.

It keeps telling me the file type is "not supported." Its a standard file used every where, so I dont see why.

You would probably get the same problem, no matter what type it is ?