[Bug libfortran/113313] execute_command_line hangs at run time

["john.harper at vuw dot ac.nz" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113313

--- Comment #2 from john.harper at vuw dot ac.nz ---
Thank you! You may wish to know that in my Ubuntu system the program 
runs properly if the function iam is used in an assignment statement not a 
print statement. (Fortran Discourse gave me the idea.) Revised program:

program test2
! f2008 using execute_command_line and assuming Linux
   implicit none
   logical foo(2)
   foo = [iam('john'),iam('JOHN')]
   print "(A,L2)",'I am john',foo(1)
   print "(A,L2)",'I am JOHN',foo(2)

contains

   logical function iam(      name)
     character(*),intent(in)::name
     integer estat
     character(len(name)+38):: cmd
     cmd = 'if [ `whoami` != "'//name//'" ]; then exit 1; fi'
     call execute_command_line(cmd,exitstat=estat)
     iam = (estat==0)
   end function iam
end program test2

  On Thu, 11 Jan 2024, kargl at gcc dot 
gnu.org wrote:

> Date: Thu, 11 Jan 2024 05:49:10 +0000
> From: kargl at gcc dot gnu.org <gcc-bugzilla@gcc.gnu.org>
> To: John Harper <john.harper@vuw.ac.nz>
> Subject: [Bug libfortran/113313] execute_command_line hangs at run time
> Resent-Date: Thu, 11 Jan 2024 18:49:26 +1300 (NZDT)
> Resent-From: <john.harper@vuw.ac.nz>
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113313
>
> kargl at gcc dot gnu.org changed:
>
>           What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                 CC|                            |kargl at gcc dot gnu.org
>
> --- Comment #1 from kargl at gcc dot gnu.org ---
> Created attachment 57034
>  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57034&action=edit
> patch to execute_command_line.c
>
> Code compiles and runs on FreeBSD.  That said, I see
>
> % gfcx -o z a.f90 -g && ./z
> I am john F
> I am JOHN F
> % valgrind ./z
> ==18812== Memcheck, a memory error detector
> ==18812== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al.
> ==18812== Using Valgrind-3.22.0 and LibVEX; rerun with -h for copyright info
> ==18812== Command: ./z
> ==18812==
> ==18812== Conditional jump or move depends on uninitialised value(s)
> ==18812==    at 0x4B0AD79: _gfortran_execute_command_line_i4
> (execute_command_line.c:203)
> ==18812==    by 0x400B2A: iam.0 (a.f90:15)
> ==18812==    by 0x400BE1: MAIN__ (a.f90:5)
> ==18812==    by 0x400CEF: main (a.f90:6)
> ==18812==
> I am john F
> ==18812== Conditional jump or move depends on uninitialised value(s)
> ==18812==    at 0x4B0AD79: _gfortran_execute_command_line_i4
> (execute_command_line.c:203)
> ==18812==    by 0x400B2A: iam.0 (a.f90:15)
> ==18812==    by 0x400C8B: MAIN__ (a.f90:6)
> ==18812==    by 0x400CEF: main (a.f90:6)
> ==18812==
> I am JOHN F
> ==18812==
> ==18812== HEAP SUMMARY:
> ==18812==     in use at exit: 0 bytes in 0 blocks
> ==18812==   total heap usage: 26 allocs, 26 frees, 9,873 bytes allocated
>
> Looking at the code around line 203 suggests that there may be some confusion
> with setting the error status.  The attached patch allows the code to
> run without the valgrind warnings.
>
> -- 
> You are receiving this mail because:
> You reported the bug.
>


-- John Harper, School of Mathematics and Statistics
Victoria Univ. of Wellington, PO Box 600, Wellington 6140, New Zealand.
e-mail john.harper@vuw.ac.nz