Fix error handling in gdbm_fetch, gdbm_firstkey, and gdbm_nextkey.

* src/gdbmfetch.c: Hanlde out of memory error.
* src/findkey.c: Set gdbm_errno to GDBM_ITEM_NOT_FOUND
if nothing was found.
* src/gdbmdelete.c: Don't set gdbm_errno after
_gdbm_findkey returns -1.  It's been done already.
* src/gdbmexp.c (gdbm_export_to_file): Return -1 if
gdbm_fetch fails.
* src/gdbmseq.c (get_next_key): Set gdbm_errno to
GDBM_ITEM_NOT_FOUND if there's no next key.
Don't call _gdbm_fatal on out of memory condition.
(gdbm_nextkey): Set gdbm_errno to
GDBM_ITEM_NOT_FOUND if there's no next key.
* src/gdbmtool.c (fetch_handler)
(firstkey_handler,nextkey_handler): Check gdbm_errno.
* src/gdbmstore.c: Handle error return from _gdbm_findkey.
* tests/gtdump.c: Likewise.
* tests/gtfetch.c: Likewise.

* doc/gdbm.texi: Document changes.
* doc/gdbm.3: Likewise.

* configure.ac: Version 1.12.90
* NEWS: Update.

* .gitignore: Update.

1 files changed, 14 insertions, 6 deletions

diff --git a/doc/gdbm.texi b/doc/gdbm.texi
index 6322a9b..6fad9d9 100644
--- a/doc/gdbm.texi
+++ b/doc/gdbm.texi
@@ -43,7 +43,7 @@ Published by the Free Software Foundation,
 51 Franklin Street, Fifth Floor
 Boston, MA 02110-1301, USA
 
-Copyright @copyright{} 1989-1999, 2007-2011 Free Software Foundation, Inc.
+Copyright @copyright{} 1989-1999, 2007-2016 Free Software Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -430,7 +430,11 @@ The @samp{dptr} field in the structure that is returned points to a
 memory block allocated by @code{malloc}.  It is the caller's
 responsibility to free it when no longer needed.
 
-If the @samp{dptr} is @samp{NULL}, no data was found.
+If the @samp{dptr} is @samp{NULL}, inspect the value of the
+@code{gdbm_errno} variable (@pxref{Variables,gdbm_errno}).  If it is
+@samp{GDBM_ITEM_NOT_FOUND}, no data was found.  Any other value means an
+error occurred.  Use @code{gdbm_strerror} function to convert
+@code{gdbm_errno} to a human-readable string.
 
 The parameters are:
 
@@ -515,8 +519,10 @@ access is not @code{key} sequential, but it is guaranteed to visit every
 @deftypefn {gdbm interface} datum gdbm_firstkey (GDBM_FILE @var{dbf})
 Initiate sequential access to the database @var{dbf}.  The returned
 value is the first key accessed in the database.  If the @samp{dptr}
-field in the returned datum is @samp{NULL}, the database contains no
-data.
+field in the returned datum is @samp{NULL}, inspect the
+@code{gdbm_errno} variable (@pxref{Variables, gdbm_errno}).  The value
+of @code{GDBM_ITEM_NOT_FOUND} means that the database contains no
+data.  Other value means an error occurred.
 
 Otherwise, @samp{dptr} points to a memory block obtained from
 @code{malloc}, which holds the key value.  The caller is responsible
@@ -530,8 +536,10 @@ value returned from a previous call to @code{gdbm_nextkey} or
 @code{gdbm_firstkey}.
 
 The function returns next key from the database.  If the @samp{dptr}
-field in the returned datum is @samp{NULL}, all keys in the database
-has been visited.
+field in the returned datum is @samp{NULL} inspect the
+@code{gdbm_errno} variable (@pxref{Variables, gdbm_errno}).  The value
+of @code{GDBM_ITEM_NOT_FOUND} means that all keys in the database
+has been visited.  Any other value means an error occurred.
 
 Otherwise, @samp{dptr} points to a memory block obtained from
 @code{malloc}, which holds the key value.  The caller is responsible