diff options
| -rw-r--r-- | src/ChangeLog | 5 | ||||
| -rw-r--r-- | src/systime.h | 3 |
2 files changed, 7 insertions, 1 deletions
diff --git a/src/ChangeLog b/src/ChangeLog index 98a4f978830..95c8ce2cb51 100644 --- a/src/ChangeLog +++ b/src/ChangeLog @@ -1,3 +1,8 @@ +2012-07-08 Paul Eggert <eggert@cs.ucla.edu> + + * systime.h (EMACS_SUB_TIME): Clarify behavior with unsigned time_t. + See <http://bugs.gnu.org/11825#29>. + 2012-07-08 Eli Zaretskii <eliz@gnu.org> * xdisp.c (fill_glyphless_glyph_string): If the face of the glyph diff --git a/src/systime.h b/src/systime.h index 938083a5ffc..a03630cf936 100644 --- a/src/systime.h +++ b/src/systime.h @@ -80,7 +80,8 @@ typedef unsigned long Time; #define EMACS_GET_TIME(time) gettime (&(time)) /* Put into DEST the result of adding SRC1 to SRC2, or of subtracting - SRC2 from SRC1. On overflow, store an extremal value. */ + SRC2 from SRC1. On overflow, store an extremal value: ergo, if + time_t is unsigned, return 0 if the true answer would be negative. */ #define EMACS_ADD_TIME(dest, src1, src2) ((dest) = timespec_add (src1, src2)) #define EMACS_SUB_TIME(dest, src1, src2) ((dest) = timespec_sub (src1, src2)) |