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-rw-r--r--manual/llio.texi22
1 files changed, 17 insertions, 5 deletions
diff --git a/manual/llio.texi b/manual/llio.texi
index 4ac6c5fa4f..1d088d8ee2 100644
--- a/manual/llio.texi
+++ b/manual/llio.texi
@@ -368,6 +368,11 @@ sending it a @code{SIGTTIN} signal isn't working.  This might happen if
 the signal is being blocked or ignored, or because the process group is
 orphaned.  @xref{Job Control}, for more information about job control,
 and @ref{Signal Handling}, for information about signals.
+
+@item EINVAL
+In some systems, when reading from a character or block device, position
+and size offsets must be aligned to a particular block size.  This error
+indicates that the offsets were not properly aligned.
 @end table
 
 Please note that there is no function named @code{read64}.  This is not
@@ -515,6 +520,11 @@ The device containing the file is full.
 This error is returned when you try to write to a pipe or FIFO that
 isn't open for reading by any process.  When this happens, a @code{SIGPIPE}
 signal is also sent to the process; see @ref{Signal Handling}.
+
+@item EINVAL
+In some systems, when writing to a character or block device, position
+and size offsets must be aligned to a particular block size.  This error
+indicates that the offsets were not properly aligned.
 @end table
 
 Unless you have arranged to prevent @code{EINTR} failures, you should
@@ -1582,11 +1592,13 @@ descriptors are checked to see if they are ready for writing; and the
 conditions.  You can pass a null pointer for any of these arguments if
 you are not interested in checking for that kind of condition.
 
-A file descriptor is considered ready for reading if it is not at end of
-file.  A server socket is considered ready for reading if there is a
-pending connection which can be accepted with @code{accept};
-@pxref{Accepting Connections}.  A client socket is ready for writing when
-its connection is fully established; @pxref{Connecting}.
+A file descriptor is considered ready for reading if a @code{read}
+call will not block.  This usually includes the read offset being at
+the end of the file or there is an error to report.  A server socket
+is considered ready for reading if there is a pending connection which
+can be accepted with @code{accept}; @pxref{Accepting Connections}.  A
+client socket is ready for writing when its connection is fully
+established; @pxref{Connecting}.
 
 ``Exceptional conditions'' does not mean errors---errors are reported
 immediately when an erroneous system call is executed, and do not