* s/template.h: Explain the relative significance of the SIGIO and

	INTERRUPT_INPUT macros.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/s/template.h b/src/s/template.h
index aab7d735d8..b7abe09e44 100644
--- a/src/s/template.h
+++ b/src/s/template.h
@@ -50,8 +50,13 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 /* Emacs can read input using SIGIO and buffering characters itself,
    or using CBREAK mode and making C-g cause SIGINT.
    The choice is controlled by the variable interrupt_input.
+
    Define INTERRUPT_INPUT to make interrupt_input = 1 the default (use SIGIO)
 
+   Emacs uses the presence or absence of the SIGIO macro to indicate
+   whether or not signal-driven I/O is possible.  It uses
+   INTERRUPT_INPUT to decide whether to use it by default.
+
    SIGIO can be used only on systems that implement it (4.2 and 4.3).
    CBREAK mode has two disadvatages
      1) At least in 4.2, it is impossible to handle the Meta key properly.
@@ -62,8 +67,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
    Another method of doing input is planned but not implemented.
    It would have Emacs fork off a separate process
    to read the input and send it to the true Emacs process
-   through a pipe.
-*/
+   through a pipe. */
 
 #define INTERRUPT_INPUT