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List:       util-linux-ng
Subject:    [PATCH 1/5] include/c: Add abs_diff macro
From:       Sean Anderson <seanga2 () gmail ! com>
Date:       2021-11-17 2:10:34
Message-ID: 20211117021038.823851-2-seanga2 () gmail ! com
[Download RAW message or body]

This macro calculates abs(a - b). It is especially useful for unsigned
numbers.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
---

 include/c.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/c.h b/include/c.h
index 354b59e29..ba799d8fd 100644
--- a/include/c.h
+++ b/include/c.h
@@ -159,6 +159,14 @@
 	_max1 > _max2 ? _max1 : _max2; })
 #endif
 
+#ifndef abs_diff
+# define abs_diff(x, y) __extension__ ({        \
+	__typeof__(x) _a = (x);			\
+	__typeof__(y) _b = (y);			\
+	(void) (&_a == &_b);			\
+	_a > _b ? _a - _b : _b - _a; })
+#endif
+
 #ifndef cmp_numbers
 # define cmp_numbers(x, y) __extension__ ({	\
 	__typeof__(x) _a = (x);			\
-- 
2.33.0

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