From 43fe90f66a0b200f6c32507428349afb45f661ca Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 25 Oct 2013 15:55:15 -0400 Subject: [PATCH] Suppress -0 in the C field of lines computed by line_construct_pts(). It's not entirely clear why some PPC machines are generating -0 here, since the underlying computation should be exactly 0 - 0. Perhaps there's some wider-than-nominal-precision calculations happening? Anyway, the best way to avoid platform-dependent results seems to be to explicitly reset -0 to regular zero. --- src/backend/utils/adt/geo_ops.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/backend/utils/adt/geo_ops.c b/src/backend/utils/adt/geo_ops.c index 25f0bfd394..41178a6540 100644 --- a/src/backend/utils/adt/geo_ops.c +++ b/src/backend/utils/adt/geo_ops.c @@ -1116,6 +1116,9 @@ line_construct_pts(LINE *line, Point *pt1, Point *pt2) line->A = (pt2->y - pt1->y) / (pt2->x - pt1->x); line->B = -1.0; line->C = pt1->y - line->A * pt1->x; + /* on some platforms, the preceding expression tends to produce -0 */ + if (line->C == 0.0) + line->C = 0.0; #ifdef GEODEBUG printf("line_construct_pts- line is neither vertical nor horizontal (diffs x=%.*g, y=%.*g\n", DBL_DIG, (pt2->x - pt1->x), DBL_DIG, (pt2->y - pt1->y));