Redirecting File STDOUT and STDERR in Intel Fortran Without Using Command Line Redirection

[Leigh_Wardle1]

Hello everyone,

How can I redirect the STDOUT and STDERR outputs to a file?

The usual method of command line redirection is not an option for me. This is because CMD is often blocked by antivirus systems, making it impractical in my work environment.

I appreciate any insights or suggestions you might have. Thank you in advance for your help!

Best regards, 
Leigh

[Arjen_Markus]

I thought a simple approach like opening files to these unit numbers would work, but the results are very mixed.

Here is my attempt:

! redir.f90 --
!     Redirecting stdout and stderr?
!
program redir
    use iso_fortran_env
    implicit none

    open( output_unit, file = 'redir.out' )
    open( error_unit, file = 'redir.err' )

    write(*,*) 'Should appear in the file "redir.out"'
    write(error_unit,*) 'Should appear in the file "redir.err"'

    !
    ! This does not appear there ...
    !
    error stop 'Should appear in the file "redir.err"'
end program redir

gfortran has the program write to "redir.out" and "redir.err",  but not the output from error stop, whereas ifx and ifort write to "redir.err" but not to "redir.out" (that appears on the screen).

[Arjen_Markus]

An alternative might be to write a small Fortran program that runs the program in question via execute_command_line and does the redirecting, thereby avoiding the direct use of CMD.

[Leigh_Wardle1]

Hi Arjen_Markus,

Many thanks for your sample code.

What I want to achieve is to handle a fatal error, for example, divide by zero.
And have the error details saved to the error file.

I have added a divide by zero to your code, so it's now:

program redir
use iso_fortran_env
implicit none
integer :: a, b, result

open( output_unit, file = 'redir.out' )
open( error_unit, file = 'redir.err' )

write(*,*) 'Should appear in the file "redir.out"'
write(error_unit,*) 'Should appear in the file "redir.err"'

!Throw a Divide by Zero error
a = 10
b = 0
result = a / b

!
! This does not appear there ...
!
error stop 'Also Should appear in the file "redir.err"'
end program redir

The divide by zero happens on this line:

result = a / b

Execution cannot progress past this line:

I was hoping that the error information:

 Should appear in the file "redir.out"
forrtl: severe (164): Program Exception - integer divide by zero
Image              PC        Routine            Line        Source
redirect_stdout_s  00E91187  _MAIN__                    17  redirect_stdout_stderr.f90
redirect_stdout_s  00E9126F  Unknown               Unknown  Unknown
redirect_stdout_s  00E93AB3  Unknown               Unknown  Unknown
redirect_stdout_s  00E93987  Unknown               Unknown  Unknown
redirect_stdout_s  00E9382D  Unknown               Unknown  Unknown
redirect_stdout_s  00E93B18  Unknown               Unknown  Unknown
KERNEL32.DLL       770405C9  Unknown               Unknown  Unknown
ntdll.dll          775478BD  Unknown               Unknown  Unknown
ntdll.dll          7754788D  Unknown               Unknown  Unknown

would appear in the file = 'redir.err', but it does not.

Regards,

Leigh

PS I received this message:
Your post has been changed because invalid HTML was found in the message body. The invalid HTML has been removed. Please review the message and submit the message when you are satisfied.
I don't know what the invalid HTML was?

[JohnNichols]

int filefd = open("foo.txt", O_WRONLY|O_CREAT, 0666);
if (!fork()) {
  close(1);//Close stdout
  dup(filefd);
  execlp("ls", "ls", NULL);
} else {
  close(filefd);
  wait(NULL);
}
return 0;

You will likely have to copy something from C and there are many examples on the net, not sure how to do it in Fortran, but there are plenty here who can tell you if it possible or do a C dll and link it in.  

I found two C examples in ten seconds, the other one is better but I lost it. 

The HTML message means you copied something from a web page or xml file and Intel discards it and then asks you to confirm, the old days with the old Intel Forum were so much easier, sad really. 

[JohnNichols]

Bring back 1984, that is my response to Intel and the three stage entry.  

[Arjen_Markus]

I implemented a straightforward and somewhat naïve program to do what I meant.

! runprogram.f90 --
!     Run a program without directly using CMD
!
program runprogram
    implicit none

    character(len=200) :: string
    integer            :: k

    call get_command( string )

    k = index( string, ' ' )
    string = string(k+1:)

    call execute_command_line( trim(string) // ' 1> runprogram.out 2> runprogram.err' )
end program runprogram

This does the trick, even though it will redirect the output to fixed files.

[andrew_4619 · Accepted solution]

The crash dump can be directed to a file with FOR_DIAGNOSTIC_LOG_FILE=<filename>  environment variable. You can set the env var from within the Fortran of you wish. I use the sdk "SetEnvironmentVariable" but there is also an IFPORT from memory setenvqq

[Leigh_Wardle1]

Thanks, Andrew,  

The FOR_DIAGNOSTIC_LOG_FILE environment variable works a treat.
I defined it with SETENVQQ.

Regards,

Leigh

[Leigh_Wardle1]

Just a postscript:

The FOR_PRINT environment variable will capture stdout.
I was hoping to combine stdout and stderr,  by setting FOR_PRINT and FOR_DIAGNOSTIC_LOG_FILE to the same file, but that did not work.

[Steve_Lionel]

If you want to write to unit * with redirection from OPEN, add /standard-semantics or /assume:noold_unit_star

However, this controls only output initiated by WRITE statements in your program - it won’t do anything for error messages.