All stdio streams get line buffering with i mode.

* socket.c (open_sockfd): We no longer need to set
stream sockets to line buffered mode here;
it's done in set_mode_props.

* stream.c (set_mode_props): If the mode specifies interactive,
streams open for writing are also switched to line buffering.

* txr.1: Documented under open-file, and open-socket.

3 files changed, 21 insertions, 6 deletions

diff --git a/socket.c b/socket.c
index ae07c816..17949a7c 100644
--- a/socket.c
+++ b/socket.c
@@ -829,7 +829,6 @@ val open_sockfd(val fd, val family, val type, val mode_str_in)
                 fd, num(errno), string_utf8(strerror(errno)), nao);
     }
 
-    setvbuf(f, (char *) NULL, _IOLBF, 0);
     return set_mode_props(m, make_sock_stream(f, family, type));
   }
 }
diff --git a/stream.c b/stream.c
index a3d60863..b98d7948 100644
--- a/stream.c
+++ b/stream.c
@@ -1236,8 +1236,13 @@ val normalize_mode(struct stdio_mode *m, val mode_str)
 
 val set_mode_props(const struct stdio_mode m, val stream)
 {
-  if (m.interactive)
+  if (m.interactive) {
+    struct stdio_handle *h = coerce(struct stdio_handle *,
+                                    cobj_handle(stream, stdio_stream_s));
+    if (h->f && m.write)
+      setvbuf(h->f, (char *) NULL, _IOLBF, 0);
     stream_set_prop(stream, real_time_k, t);
+  }
   return stream;
 }
 
diff --git a/txr.1 b/txr.1
index a09f1abe..0953ae26 100644
--- a/txr.1
+++ b/txr.1
@@ -34398,7 +34398,14 @@ is used.
 The option letter
 .str i
 is supported. If present, it will create a stream which has the real-time
-property set.
+property set. For a description of the semantics, see the
+.code real-time-stream-p
+function. Briefly, this property affects the semantics of lazy lists which draw
+input from the stream.
+In addition, for a stream opened for writing or reading and writing, the
+.str i
+mode letter specifies that the stream will be line-buffered. This means that an
+implicit flush operation takes place whenever the newline character is output.
 
 .coNP Function @ open-tail
 .synb
@@ -37780,9 +37787,13 @@ data flow, the default mode string is
 rather than the usual
 .strn r .
 
-Stream sockets are created line-buffered. Therefore, programs which communicate
-using textual, line-oriented protocols over sockets need not execute flush operations
-after each line.
+Like other stream times, stream sockets are buffered and marked as no
+non-real-time streams. Specifying the
+.str i
+mode in
+.metn mode-string
+marks a socket as a real-time-stream, and, if it is opened for writing
+or reading and writing, changes it to use line buffering.
 
 .coNP Functions @ sock-family and @ sock-type
 .synb