>From c.l.f, Richard Maine:
2003 9.2.3.3, "File position after data
transfer", 3rd para
"For a formatted stream output statement, if no error condition
occurred, the terminall point of the file is set to the highest-numbered
position to which data was transferred by the statement."
Currently, we don't. The following program shouldn't work:
program main
implicit none
character(len=6) :: c
integer :: i
open(20,file="foo.txt",form="formatted",access="stream")
write(20,'(A)') '123456'
write(20,'(A)') 'abcdef'
write(20,'(A)') 'qwerty'
rewind 20
! Skip over the first line
read(20,'(A)') c
! Save the position
inquire(20,pos=i)
! Read in the complete line...
read(20,'(A)') c
! Write out the first four characters
write(20,'(A)',pos=i,advance="no") 'ASDF'
! Fill up the rest of the line. Here, we know the length. If we
! don't, things will be a bit more complicated.
write(20,'(A)') c(5:6)
! Copy the file to standard output
rewind 20
do i=1,3
read(20,'(A)') c
print '(A)',c
end do
close (20)
end program main
It currently prints
123456
ASDFef
qwerty
which is wrong.
--
Summary: Formatted stream I/O write should truncate
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: libfortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: tkoenig at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35132
