topic Separate to your USEROPEN in Intel® Fortran Compiler

FILENAME is "undefined address" with USEROPEN

Burton_R_ — Mon, 08 Apr 2013 16:39:35 GMT

I am trying to implement writing to a named pipe with a USEROPEN function (written in Fortran). when the useropen function is called, the FILENAME is "Undefined Address". If I simply hard-code the pipe name everything works as expected, but obviously that not going to work for production. Here's my code. I am a Fortran newb, so please don't hesitate to critique any part of this.

module fortranpipe

implicit none

contains

subroutine writetopipe()

!dec$ attributes dllexport :: writetopipe

!dec$ attributes alias : "writetopipe" :: writetopipe

implicit none

integer*4 :: i

OPEN(UNIT=10,FILE='\\.\pipe\testpipe',STATUS='OLD', ACTION='WRITE', useropen = uopen)

print*, "open called"

do i = 1, 10

write (10, *) 'Hello World!'

end do

close(10)

end subroutine

INTEGER FUNCTION UOPEN(FILENAME, DESIRED_ACCESS, SHARE_MODE, A_NULL, CREATE_DISP, FLAGS_ATTR, B_NULL, UNIT, FLEN)

!DEC$ ATTRIBUTES C, ALIAS:'_UOPEN' :: UOPEN

!DEC$ ATTRIBUTES REFERENCE :: FILENAME

!DEC$ ATTRIBUTES REFERENCE :: DESIRED_ACCESS

!DEC$ ATTRIBUTES REFERENCE :: SHARE_MODE

!DEC$ ATTRIBUTES REFERENCE :: CREATE_DISP

!DEC$ ATTRIBUTES REFERENCE :: FLAGS_ATTR

!DEC$ ATTRIBUTES REFERENCE :: UNIT

USE IFWIN

implicit none

integer*4 :: DESIRED_ACCESS, SHARE_MODE, CREATE_DISP, FLAGS_ATTR, UNIT, A_NULL, B_NULL, FLEN, hFile

CHARACTER*(FLEN) FILENAME

character*(FLEN+1) :: pipename

TYPE(T_SECURITY_ATTRIBUTES), POINTER :: NULL_SEC_ATTR

logical :: waitstatus

!FLAGS_ATTR = FLAGS_ATTR + FILE_FLAG_WRITE_THROUGH

DESIRED_ACCESS = GENERIC_WRITE

SHARE_MODE = 0

CREATE_DISP = OPEN_EXISTING

FLAGS_ATTR = FILE_ATTRIBUTE_NORMAL

pipename = '\\.\pipe\testpipe' // char(0)

waitstatus = WaitNamedPipe(pipename, 1000)

UOPEN = CreateFile( pipename, DESIRED_ACCESS, SHARE_MODE, NULL_SEC_ATTR, CREATE_DISP, 0, 0 )

RETURN

END function

end module

Separate to your USEROPEN

IanH — Mon, 08 Apr 2013 22:46:44 GMT

Separate to your USEROPEN question - consider (if you wanted to customise the CreateFile or pipe connection in some way the following might not be applicable) just using a normal Fortran OPEN statement to open the pipe and handling the specific "pipe not available" error code (perhaps in a loop with some sort of delay between attempts. This is simpler and also avoids the race condition that exists in your current approach - there is a finite time between WaitNamedPipe and CreateFile where another process could steal the pipe.

I suspect what is happening is that you are relying on the debugger to find out what filename is, and the debugger is telling fibs - the actual filename is ok (and it already includes the null terminator). But do note that Fortran pointers and C pointers are different - you never define NULL_SEC_ATTR so the reference to it in the CreateFile call is an error. Instead simply pass NULL for that parameter.

you're absolutely correct on

Burton_R_ — Mon, 08 Apr 2013 23:03:44 GMT

you're absolutely correct on both points. I had originally tried opening the pipe without the USEROPEN function, but failed because some of the parameters were wrong. now that I have all that worked out with the USEROPEN working, opening the pipe without USEROPEN is also working. Also, now that I have the remaining options correct, i was stopping in the debugger to inspect FILENAME, but never tried just passing FILENAME to CreateFile. THANKS!

Here's the code i ended up

Burton_R_ — Mon, 08 Apr 2013 23:54:24 GMT

Here's the code i ended up with:

module fortranpipe

implicit none

contains

subroutine writetopipe()

!dec$ attributes dllexport :: writetopipe

!dec$ attributes alias : "writetopipe" :: writetopipe

use kernel32

implicit none

integer*4 :: i, ios, lasterror

logical :: waitstatus

character*17 :: pipename

pipename = '\\.\pipe\testpipe'

open(unit=10, file=pipename, status='OLD', action='WRITE', iostat=ios)

if (ios == 0) exit

waitstatus = WaitNamedPipe(pipename // char(0), 1000)

lasterror = GetLastError()

if (waitstatus == .false. .OR. lasterror /= 0) exit

end do

if (ios /= 0) then

! do something with the err

endif

print*, "open called"

do i = 1, 10

write (10, *) 'Hello World!'

end do

close(10)

end subroutine

end module