Correction in the documentation of 'io.lines'

The loop does not end on end of file, but when the iterator function
fails to read a value. (In particular, the format "a" never fails,
so a loop with 'io.lines(fname, "a")' never ends.)

liolib.c

@@ -624,7 +624,7 @@ static int io_readline (lua_State *L) {
     lua_pushvalue(L, lua_upvalueindex(3 + i));
   n = g_read(L, p->f, 2);  /* 'n' is number of results */
   lua_assert(n > 0);  /* should return at least a nil */
-  if (lua_toboolean(L, -n))  /* read at least one value? */
+  if (!lua_isnil(L, -n))  /* read at least one value? */
     return n;  /* return them */
   else {  /* first result is nil: EOF or error */
     if (n > 1) {  /* is there error information? */

manual/manual.of

@@ -7926,8 +7926,8 @@ instead of returning an error code.
 Opens the given file name in read mode
 and returns an iterator function that
 works like @T{file:lines(@Cdots)} over the opened file.
-When the iterator function detects the end of file,
-it returns no values (to finish the loop) and automatically closes the file.
+When the iterator function fails to read any value,
+it automatically closes the file.
 Besides the iterator function,
 @id{io.lines} returns three other values:
 two @nil values as placeholders,
@@ -7941,7 +7941,8 @@ to @T{io.input():lines("l")};
 that is, it iterates over the lines of the default input file.
 In this case, the iterator does not close the file when the loop ends.
 
-In case of errors this function raises the error,
+In case of errors opening the file,
+this function raises the error,
 instead of returning an error code.
 
 }
@@ -8053,9 +8054,6 @@ starting at the current position.
 Unlike @Lid{io.lines}, this function does not close the file
 when the loop ends.
 
-In case of errors this function raises the error,
-instead of returning an error code.
-
 }
 
 @LibEntry{file:read (@Cdots)|