I am using Fortran to make a subroutine to use in a CFD shallow water software.
I have written this code to read and use the values stored.
PROGRAM hieto
! Calcula la precipitacion efectiva en funcion del tiempo
!IMPLICIT NONE
real::a
!Abrir CSV
!OPEN(UNIT=10,FILE="datos.txt",FORM="formatted",STATUS="replace",ACTION="readwrite",ACCESS='sequential')
open(unit=10, file='datos.txt')
!Leer el archivo
read(10, *, iostat=ios)a
print*,ios
print*, a
close (UNIT=10)
END PROGRAM hieto
My text file datos, looks like this
1
2
3
When I run the code as is, I get the following output
-1
0.0000000000
Process return 0 (0x0) execution time: 0.002 s
the first number in the row one is one not zero, so I don't know why this happens.
And if I remove the iostat=ios from the read statement, I get the following error:
At ine 13 (the line od the read stament) of file /home/Dropbox/scripts_tesis/fortran/hieto_telemac.f90 (unit=10, file=datos.txt')
Fortran runtime error: end of file.
Proceess returned 2 (0x2)
I have read some answers here so I tried adding end=3 in the read statement, and also to end my text file with a blank line at the end.
The end=3 gives an error saying 3 is not a defined label and putting a blank row in the text file does nothing.
I am using ubuntu 16.04 LTS and Gfortran compiler.
What happens is that your file is empty.
Make sure that there is indeed a file called datos.txt in that directory. Pay attention to the exact name. datos.txt and just datos is not the same thing.
If you tried to open it before with the commented command that includes STATUS="replace" your old file would have been replaced.
And because the file is empty, you didn't real anything useful. If iostat is non-zero, and your is -1, then the value of the variable being read is undefined. So your a is undefined. Again, because your file is empty.
Additionally, you cannot just blindly put end=3 in your code because you saw it somewhere on Stack Overflow. You must first understand what it is supposed to do. There is no reason to combine iostat= and end=. The iostat is perfectly sufficient.
Related
I have a Fortran program that needs to read ASCII files, however the list of files sometimes includes a file of size 0. The program then crashes when trying to read this file. I have not find any way so far that will allow me to flag such a file.
I have following READ statement in my code
read(10,220,END=320,ERR=195)parm(1:)
although I expect code to go to statement 195, or to statement 320, without crashing, it crashes
this is where the code crashes when the file size is zero, with the following messages
...
fmt: end of file
apparent state: unit 10 named junko.con
last format: (A)
lately reading sequential formatted external IO
I tried using the INQUIRE statement
inquire (unit=10,SIZE=nsize), but the program would not compile
the OPEN statement did not give any error when opening the zero size file, and the values of IOSTAT was the same, irrespective of the file size
As Ian noted, any modern Fortran compiler should have INQUIRE. A simple test of
program foo
integer sz
inquire(file='tmp.dat',size=sz)
print *, sz
end program foo
with an empty tmp.dat file sets sz=0.
I'm trying to read some data from a file, and the endfile record detection is important to stop reading. However, depending of the array dimensions of the array used to read data, I cannot detect properly the endfile record and my Fortran program stops.
The program is below:
!integer, dimension(3) :: x ! line 1.1
!integer, dimension(3,10) :: x ! line 1.2
integer, dimension(10,3) :: ! line 1.3
integer :: status,i=1
character(len=100) :: error
open( 30, file='data.dat', status='old' )
do
print *,i
!read( 30, *, iostat=status, iomsg=error ) x ! line 2.1
!read( 30, *, iostat=status, iomsg=error ) x(:,i) ! line 2.2
read( 30, *, iostat=status, iomsg=error ) x(i,:) ! line 2.3
if ( status < 0 ) then print *,'EOF'
print *,'total of ',i-1,' lines read.'
exit
else if ( status > 0 ) then
print *,'error cod: ',status
print *,'error message: ', error
stop
else if ( status == 0 ) then
print *,'reading ok.'
i = i + 1
end if
end do
With 'data.dat' file been:
10 20 30
30 40 50
When lines 1.3 and 2.3 are uncommented the mentioned error appears:
error cod: 5008
error message: Read past ENDFILE record
However, using lines 1.1 and 2.1, or 1.2 and 2.2, the program works, detecting endfile record.
So, I would like some help on understanding why I cannot use lines 1.3 and 2.3 to read properly this file, since I'm giving the correct number of array elements for read command.
I'm using gfortran compiler, version 6.3.0.
EDIT: simpler example
the following produces a 5008 "Read past ENDFILE record" error:
implicit none
integer x(2,2),s
open(20,file='noexist')
read(20,*,iostat=s)x
write(*,*)s
end
if we make x a scalar or a one-d array ( any size ) we get the expected -1 EOF flag. It doesn't matter if the file actually doesn't exist or is empty. If the file contains some, but not enough, data its hard to make sense of which return value you might get.
I am not sure if I am expressing myself correctly but it has to do with the way fortran is reading and storing 2d-arrays. When you are using this notation: x(:,i), the column i is virtually expanded in-line and the items are read using this one line of code. In the other case where x(i,:) is used, the row i is read as if you called read multiple times.
You may use implied loops if you want to stick with a specific shape and size. For example you could use something like that:read( 30, *, iostat=status, iomsg=error ) (x(i,j), j=1,3)
In any case you should check that your data are stored properly (as expected at least) in variable x.
Please note this is only a guess. Remember that Fortran stores arrays in column major order. When gfortran compiles read() x(:,i), the 3 memory locations are next to each other so in the executable, it produces a single call to the operating system to read in 3 values from the file.
Now when read() x(i,:) is compiled, the three data elements x(i,1), x(i,2) and x(i,3) are not in contiguous memory. So I am guessing the executable actually has 3 read calls to the operating system. The first one would trap the EOF but the 2nd one gives you the read past end of file error.
UPDATE: I have confirmed that this does not occur with Intel's ifort. gfortran seems to have had a similar problem before: Bad IOSTAT values when readings NAMELISTs past EOF. Whether this is a bug or not is debatable. The code certainly looks like it should trap an EOF.
I'm trying to read data from a mesh file in Fortran 2003, but I'm getting an unexpected end of file runtime error. Some lines in the file seem to be skipped by the read command. For example, with this sample.txt file :
1 2 2 0 1 1132 1131 1165
2 2 2 0 2 1099 1061 1060
I want to read the first integer from each line, so my program is :
program read_file
implicit none
integer :: ierr, i, j
open(unit=10,file='sample.txt',status='old',action='read',iostat=ierr)
read(10,*) i
read(10,*) j
write(*,*) i, j
end program read_file
And at runtime, I'm getting
Fortran runtime error: End of file
What is odd is that if I force a carriage return at the end of the file, the program will read the two integers just fine.
If you really need to fix this on the read side (ie. properly terminating the last line of the file is not practical for some reason ) you might try reading each line into a string, then internal reading from the string:
character*80 line
integer i
do ..
read(unit,'(a)')line
read(line,*)i
enddo
Of course this may or may not work depending on the compiler as well..
Obviously fixing the file is the best option ( Whatever program is creating this file should be fixed )
Every record in a sequential file must be properly terminated. The records in text files are the lines. They must be properly terminated. In some editors that means you must add an empty line to the end. Every line containing data must be terminated.
Some compilers are less sensitive to this issue than others and will terminate the last record for you.
I made a Fortan routine to read a weather file into my program. This file contains 2 header lines and then lines of data for every 10 minutes and is therefor 52562 lines long.
When reading the file with the code below it returns the error Fortran runtime error: End of file for i = 52548 in the do-loop.
bdst=600
allocate(clidat(int(3.1536d7/bdst),15))
open(2001,file='church_10m.cli',action='read')
read(2001,*); read(2001,*)
do i=1,size(clidat,1)
read(2001,*) clidat(i,:)
enddo
close(2001);
The file used can be found using this public dropbox link: church_10m.cli. I checked and the file does contain the 52562 lines. The line corresponding to i = 52548 is the last line of the file. The line corresponding to i=1 is the third line of the file (which starts with 0). So I suspect that some lines are skipped in between. Any thoughts why this happens?
If a line doesn't contain 15 values (the size of clidat) the read statement just goes to the next line and reads the next values. There were a couple of lines in the church_10m.cli file that didn't have enough values. (for example line 1957).
This was a result of the conversion from an excel file to a txt file.
I compile a fortran 77 code using gfortran and get the following error:
10 open (23,file=outfile,status='old',access='append',err=10)
1
Warning: Branch at (1) may result in an infinite loop
This happens several times.
One of the output files looks like the following:
^L6a10È <90> ) &<9b>LÓLÓLÕ<91><90> <90> <90> È <8e><9b>LÓLÓLÕ<93>2
!MERCURY ¢¤õ/!ô<8a><8a><90> ÿ<90> ÿ<90> ÿÌÖÏ©ü}M<91>
"VENUS «}>±{©±<8b><90> ÿ<90> ÿ<90> ÿʺ93¿<8d>d<91>
However, it should just look like a table of text.
Any ideas?
Your line of code
10 open (23,file=outfile,status='old',access='append',err=10)
specifies that the open statement should transfer control to itself (label 10) in case an error is encountered, so any error could trigger an infinite loop. It also suppresses the output of error messages. If you want to just check for an error status, I would suggest using the iostat and/or iomsg (Fortran 2003) arguments:
open (23, file=outfile, status='old', access='append', iostat=ios, iomsg=str)
Here ios is an integer that will be zero if no errors occur and nonzero otherwise, and str is a character variable that will record the corresponding error message.
The err= argument in your open statement specifies a statement label to branch to should the open fail for some reason. Your code specifies a branch to the line labelled 10 which happens to be the line containing the open statement. This is probably not a good idea; a better idea would be to branch to a line which deals gracefully with an error from the open statement.
The warning from gfortran is spot on.
As to the apparent garbage in your output file, without sight of the code you use to write the garbage (or what you think are pearls perhaps) it's very difficult to diagnose and fix that problem.