1 files changed, 69 insertions, 13 deletions

diff --git a/src/lib/libc/string/strerror.3 b/src/lib/libc/string/strerror.3
index c9d8504dbb..f3f80432c3 100644
--- a/src/lib/libc/string/strerror.3
+++ b/src/lib/libc/string/strerror.3
@@ -13,11 +13,7 @@
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 .\"    documentation and/or other materials provided with the distribution.
-.\" 3. All advertising materials mentioning features or use of this software
-.\"    must display the following acknowledgement:
-.\"     This product includes software developed by the University of
-.\"     California, Berkeley and its contributors.
-.\" 4. Neither the name of the University nor the names of its contributors
+.\" 3. Neither the name of the University nor the names of its contributors
 .\"    may be used to endorse or promote products derived from this software
 .\"    without specific prior written permission.
 .\"
@@ -33,12 +29,11 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"     from: @(#)strerror.3    6.9 (Berkeley) 6/29/91
-.\"     $Id: strerror.3,v 1.1.1.1 1995/10/18 08:42:22 deraadt Exp $
+.\"     $OpenBSD: strerror.3,v 1.10 2011/07/25 00:38:53 schwarze Exp $
 .\"
-.Dd June 29, 1991
+.Dd $Mdocdate: July 25 2011 $
 .Dt STRERROR 3
-.Os BSD 4
+.Os
 .Sh NAME
 .Nm strerror
 .Nd get error message string
@@ -46,15 +41,63 @@
 .Fd #include <string.h>
 .Ft char *
 .Fn strerror "int errnum"
+.Ft int
+.Fn strerror_r "int errnum" "char *strerrbuf" "size_t buflen"
 .Sh DESCRIPTION
 The
 .Fn strerror
-function returns a pointer to the language-dependent error message
-string affiliated with an error number.
+and
+.Fn strerror_r
+functions map the error number
+.Fa errnum
+to a language-dependent error message string.
 .Pp
-The array pointed to is not to be modified by the program, but may be
-overwritten by subsequent calls to
+.Fn strerror
+returns a string containing a maximum of
+.Dv NL_TEXTMAX
+characters, including the trailing NUL.
+This string is not to be modified by the calling program,
+but may be overwritten by subsequent calls to
 .Fn strerror .
+.Pp
+.Fn strerror_r
+is a thread safe version of
+.Fn strerror
+that places the error message in the specified buffer
+.Fa strerrbuf .
+.Sh RETURN VALUES
+.Fn strerror
+returns a pointer to the error message string.
+If an error occurs, the error code is stored in
+.Va errno .
+.Pp
+.Fn strerror_r
+returns zero upon successful completion.
+If an error occurs, the error code is stored in
+.Va errno
+and the error code is returned.
+.Sh ERRORS
+.Fn strerror
+and
+.Fn strerror_r
+may fail if:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+.Fa errnum
+is not a valid error number.
+The returned error string will consist of an error message that includes
+.Fa errnum .
+.El
+.Pp
+.Fn strerror_r
+may fail if:
+.Bl -tag -width Er
+.It Bq Er ERANGE
+The error message is larger than
+.Fa buflen
+characters.
+The message will be truncated to fit.
+.El
 .Sh SEE ALSO
 .Xr intro 2 ,
 .Xr perror 3 ,
@@ -64,3 +107,16 @@ The
 .Fn strerror
 function conforms to
 .St -ansiC .
+The
+.Fn strerror_r
+function conforms to
+.St -p1003.1 .
+.Sh HISTORY
+The
+.Fn strerror
+function first appeared in
+.Bx 4.3 Reno .
+The
+.Fn strerror_r
+function first appeared in
+.Ox 3.3 .