[commit] breakpoint.c (breakpoint_cond_eval): Fix and enhance comment.

[Doug Evans <xdje42@gmail.com>]

Hi.

fyi, I committed this.
It took a bit to determine why breakpoint_cond_eval returns
the inverted condition result, so I wrote it down.

2013-11-13  Doug Evans  <xdje42@gmail.com>

	* breakpoint.c (breakpoint_cond_eval): Fix and enhance comment.

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 36252ee..f0b496d 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -4649,10 +4649,12 @@ bpstat_print (bpstat bs, int kind)
   return PRINT_UNKNOWN;
 }
 
-/* Evaluate the expression EXP and return 1 if value is zero.  This is
-   used inside a catch_errors to evaluate the breakpoint condition.
+/* Evaluate the expression EXP and return 1 if value is zero.
+   This returns the inverse of the condition because it is called
+   from catch_errors which returns 0 if an exception happened, and if an
+   exception happens we want execution to stop.
    The argument is a "struct expression *" that has been cast to a
-   "char *" to make it pass through catch_errors.  */
+   "void *" to make it pass through catch_errors.  */
 
 static int
 breakpoint_cond_eval (void *exp)