From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 932903857B93; Wed,  3 Jan 2024 19:51:19 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 932903857B93
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1704311479;
	bh=jFL4SSQPfXkLucLLOOc1lJ88SOpoWW/kY5QRYVowdcM=;
	h=From:To:Subject:Date:From;
	b=em+k2Ag4Xbxi+cqxcoWzT8bmjqTY+nORwGQMQM0jM/Nuu9g7ClpcO99wkZLJod2f+
	 OI6VTYPM/McHPS3SLMZIL3KdYx/ayFkHsnOHUUPOXUiRsMpv7AbtQ3KuEEse/GFxwL
	 kjbpkVCxnfS1VR1dYWujSbtfuj8JZFdiJwS70AYM=
From: "kargl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libfortran/113223] New: NAMELIST internal write missing leading
 blank character
Date: Wed, 03 Jan 2024 19:51:19 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: libfortran
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: kargl at gcc dot gnu.org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status
 bug_severity priority component assigned_to reporter target_milestone
Message-ID: <bug-113223-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113223

            Bug ID: 113223
           Summary: NAMELIST internal write missing leading blank
                    character
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libfortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kargl at gcc dot gnu.org
  Target Milestone: ---

Found at https://github.com/llvm/llvm-project/issues/76798

Program test_namelist_blank
  Integer :: i,j
  Character(300) ::s
  Namelist /nml1/i,j

  i =3D 99
  j =3D 42
  Write (s,NML=3Dnml1)
  Write (*,'("Internal ",A)') Merge('ok ','bug',s(1:1)=3D=3D' ')
  Write (*,NML=3Dnml1)
End Program test_namelist_blank

F2018
13.11.4.3 Namelist output records
...
Except for new records created by explicit formatting within a defined
output procedure or by continuation of delimited character sequences,
each output record begins with a blank character.

Patch

diff --git a/libgfortran/io/write.c b/libgfortran/io/write.c
index f94e180ba33..a7cf5d9b233 100644
--- a/libgfortran/io/write.c
+++ b/libgfortran/io/write.c
@@ -2466,6 +2466,8 @@ namelist_write (st_parameter_dt *dtp)
        dtp->u.p.nml_delim =3D '\0';
     }

+  if (is_internal_unit (dtp))
+    write_character (dtp, " ", 1, 1, NODELIM);
   write_character (dtp, "&", 1, 1, NODELIM);

   /* Write namelist name in upper case - f95 std.  */=