From: Stathis Kamperis <ekamperi@gmail.com>
Date: Sat, 7 Mar 2009 15:58:30 +0000 (+0000)
Subject: isatty(3): mention return values and error codes
X-Git-Tag: v2.3.1~238
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/0ab0bcb6455df20e4d40b518eaccaf8da91de821

isatty(3): mention return values and error codes
---

diff --git a/lib/libc/gen/ttyname.3 b/lib/libc/gen/ttyname.3
index eb3769d9fe..6edcb7bc8b 100644
--- a/lib/libc/gen/ttyname.3
+++ b/lib/libc/gen/ttyname.3
@@ -83,12 +83,12 @@ function
 gets the related device name of
 a file descriptor for which
 .Fn isatty
-is true
+is true.
 .Pp
 The
 .Fn ttyname_r
 function is a thread-safe version of
-.Fn ttyname
+.Fn ttyname .
 .Pp
 The
 .Fn ttyslot
@@ -98,6 +98,12 @@ fetches the current process' control terminal number from the
 file entry.
 .Sh RETURN VALUES
 The
+.Fn isatty
+function
+returns 1 if the file descriptor refers to a valid terminal
+device and 0 otherwise.
+.Pp
+The
 .Fn ttyname
 function
 returns the null terminated name if the device is found and
@@ -117,6 +123,21 @@ the value zero is returned.
 .It Pa /dev/\(**
 .It Pa /etc/ttys
 .El
+.Sh ERRORS
+The
+.Fn isatty
+function
+may fail if:
+.Bl -tag -width Er
+.It Bq Er EBADF
+The
+.Fa fd
+is not a valid open file descriptor.
+.It Bq Er ENOTTY
+The
+.Fa fd
+is not associated with a terminal.
+.El
 .Sh SEE ALSO
 .Xr ioctl 2 ,
 .Xr ttys 5