https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123906
Bug ID: 123906
Summary: INQUIRE w/IOLENGTH can return bad value with character
strings
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: w6ws at earthlink dot net
Target Milestone: ---
This example has a character string of length 5, followed by a numeric
variable, in the midst of the record. The INQUIRE statement is apparently not
rounding up to the next 4-byte boundary - so the record length returned is too
small. Later when performing a direct access WRITE, the program aborts.
program daio5
implicit none
integer, parameter :: unit_no = 24
integer :: i, i1, iolen
logical :: l, pf
character(5) :: s
real :: r
complex :: c
complex, parameter :: cval = (12.34, 56.78)
inquire (iolength=iolen) l, s, i, r
print *, 'recl =', iolen
open (unit_no, file='fort.24', access='direct', recl=iolen)
! Write some records
do, i=1, 10
l = mod (i,2) == 0
write (unit_no, rec=i) l, '12345', i, i+0.5, cval
end do
! Read them back and check for validity
do, i=1, 10
l = .false.; s = 'uini'; i1 = -42; r = -42.42
read (unit_no, rec=i) l, s, i1, r, c
pf = (l .eqv. mod (i, 2) == 0) .and. &
(s == '12345') .and. &
(i == i1) .and. &
(abs (r - (i + 0.5)) < 0.0001) .and. &
(c == cval)
print *, 'l, s, i1, r =', l, s, i1, r, c
print *, 'read', i, merge ('pass', 'fail', pf)
end do
close (unit_no)
end program
$ gfortran -g daio5.f90
$ rm fort.24
$ ./a.out
recl = 17
At line 20 of file daio5.f90 (unit = 24, file = 'fort.24')
Fortran runtime error: Write exceeds length of DIRECT access record
Error termination. Backtrace:
#0 0x401538 in daio5
at /home/wws/computer/fortran/lfortran/wws/daio5.f90:20
#1 0x40195c in main
at /home/wws/computer/fortran/lfortran/wws/daio5.f90:38
$ od -c fort.24
0000000 \0 \0 \0 \0 1 2 3 4 5 001 \0 \0 \0 \0 \0 300
0000020 ?
0000021
$ gfortran --version
GNU Fortran (GCC) 16.0.0 20251209 (experimental)
Copyright (C) 2025 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$
