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authorBartosz Golaszewski <bgolaszewski@baylibre.com>2015-04-16 12:43:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-17 09:03:54 -0400
commitf2027543b9cb47e1853d8c34fe931e2fcee5cb65 (patch)
tree75f849fec3effd981186b501974ea7367d346f0d /Documentation
parent95d119528b0b8440a63bc13904e9873fc3a70503 (diff)
downloadlinux-f2027543b9cb47e1853d8c34fe931e2fcee5cb65.tar.bz2
documentation: update CodingStyle on local variables naming in macros
Describe proper naming convention for local variables in macros resembling functions. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/CodingStyle13
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle
index 449a8a19fc21..4d4f06d47e06 100644
--- a/Documentation/CodingStyle
+++ b/Documentation/CodingStyle
@@ -659,6 +659,19 @@ macros using parameters.
#define CONSTANT 0x4000
#define CONSTEXP (CONSTANT | 3)
+5) namespace collisions when defining local variables in macros resembling
+functions:
+
+#define FOO(x) \
+({ \
+ typeof(x) ret; \
+ ret = calc_ret(x); \
+ (ret); \
+)}
+
+ret is a common name for a local variable - __foo_ret is less likely
+to collide with an existing variable.
+
The cpp manual deals with macros exhaustively. The gcc internals manual also
covers RTL which is used frequently with assembly language in the kernel.