https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88776
Bug ID: 88776
Summary: Namelist read from stdin: loss of data
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libfortran
Assignee: unassigned at gcc dot gnu.org
Reporter: anlauf at gmx dot de
Target Milestone: ---
Reading namelist from unit 5 may skip valid data later when an error is
encountered. This problem does not occur when another unit number is used.
Example:
% cat gfcbug154.f90
program nmlbug
implicit none
integer :: i, stat, nnml
nnml = 5 ! No problem with nnml = 10
! nnml = 10
open (nnml, file="gfcbug154.dat", action="read")
do i = 1, 3
print *, "# Read namelist", i
call read_nml_type_2
print *
end do
contains
subroutine read_nml_type_2
!----------------------------------------------------------
! variant 2 of namelist input: chan = real char(len=*) real
!----------------------------------------------------------
type t_chan
real :: ichan = -1.
character(len=10) :: flag = ''
real :: band = -1.
end type t_chan
type(t_chan) :: chan(2)
namelist /CHAN_NML/ chan
chan(:) = t_chan(-1.,'',-1.)
stat = 0
read (nnml, nml=CHAN_NML, iostat=stat, end=99)
print *, "read_nml_type_2: stat=", stat
print *, "chan(1)=", chan(1)
print *, "chan(2)=", chan(2)
return
99 stop "EOF"
end subroutine read_nml_type_2
end program nmlbug
% cat gfcbug154.dat
&CHAN_NML
chan = 3 '#1 ' '0.1'
6 '#1 ' 0.8
/
&CHAN_NML
chan = 4 '#2 ' 0.1
7 '#2 ' 0.2
/
&CHAN_NML
chan = 5 '#3 ' 0.3
8 '#3 ' 0.4
/
The above code outputs:
# Read namelist 1
read_nml_type_2: stat= 5010
chan(1)= 4.00000000 #2 0.100000001
chan(2)= 7.00000000 #2 0.200000003
# Read namelist 2
read_nml_type_2: stat= 0
chan(1)= 5.00000000 #3 0.300000012
chan(2)= 8.00000000 #3 0.400000006
# Read namelist 3
STOP EOF
whereas with e.g. unit 10 it (correctly) outputs:
# Read namelist 1
read_nml_type_2: stat= 5010
chan(1)= 3.00000000 #1 -1.00000000
chan(2)= -1.00000000 -1.00000000
# Read namelist 2
read_nml_type_2: stat= 0
chan(1)= 4.00000000 #2 0.100000001
chan(2)= 7.00000000 #2 0.200000003
# Read namelist 3
read_nml_type_2: stat= 0
chan(1)= 5.00000000 #3 0.300000012
chan(2)= 8.00000000 #3 0.400000006
For some reason, when an error is encountered during the first read,
it correctly sets the error status, but apparently continues to the
second namelist instance.
