https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113313
--- Comment #9 from john.harper at vuw dot ac.nz ---
This variant of my test program (now called test4) hangs with gfortran
but not with other compilers if iam is written to output_unit (like the
original version) or to a file with a different positive unit number, but
it does not hang if written to a file with a negative unit number obtained
by opening it with newunit=u. Its user has those 3 choices at run time.
I hope it helps you explore this oddity of gfortran.
program test4
use iso_fortran_env, only: output_unit
! Linux with f2008 (newunit=, execute_command_line, allocatable scalar)
implicit none
integer:: u = output_unit+20
character:: ch*1, line(2)*80
print "(A)",'Output from iam will go to unit u;', &
' u=output_unit if you enter a, or',&
' unit=u (u>0) if you enter b, or',&
' newunit=u (u<0) if you enter anything else.'
read "(A)", ch
if(ch=='a') then
u = output_unit
else if(ch=='b') then
open( unit=u,file='test4.out')
else
open(newunit=u,file='test4.out')
end if
print "(A,I0)",'Output from iam will be written to unit ',u
write(u,"(A,L2)")'I am john',iam('john')
write(u,"(A,L2)")'I am JOHN',iam('JOHN')
if(u/=output_unit) then
rewind u
read(u,"(A)") line
print "(A)", line
close(u,status='delete')
end if
contains
logical function iam( name)
character(*),intent(in)::name
integer estat
character(:),allocatable:: cmd
cmd = 'if [ `whoami` != "'//name//'" ]; then exit 1; else exit 0; fi'
call execute_command_line(cmd,exitstat=estat)
iam = (estat==0)
end function iam
end program test4
-- John Harper, School of Mathematics and Statistics
Victoria Univ. of Wellington, PO Box 600, Wellington 6140, New Zealand.
e-mail john.har...@vuw.ac.nz
