[PATCH v2] staging: comedi: rewrite macro function with GNU extension typeof

Jules Irenge jbi.octave at gmail.com
Mon Nov 4 16:33:31 UTC 2019


Rewrite macro function with the GNU extension typeof
to remove a possible side-effects of MACRO argument reuse "x".
 - Problem could rise if arguments have different types
and different use though.

Signed-off-by: Jules Irenge <jbi.octave at gmail.com>
---
v1 - had no full commit log message, with changes not intended to be in the patch 
v2 - remove some changes not intended to be in this driver
     include note of a potential problem
 drivers/staging/comedi/comedi.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/comedi/comedi.h b/drivers/staging/comedi/comedi.h
index 09a940066c0e..a57691a2e8d8 100644
--- a/drivers/staging/comedi/comedi.h
+++ b/drivers/staging/comedi/comedi.h
@@ -1103,8 +1103,10 @@ enum ni_common_signal_names {
 
 /* *** END GLOBALLY-NAMED NI TERMINALS/SIGNALS *** */
 
-#define NI_USUAL_PFI_SELECT(x)	(((x) < 10) ? (0x1 + (x)) : (0xb + (x)))
-#define NI_USUAL_RTSI_SELECT(x)	(((x) < 7) ? (0xb + (x)) : 0x1b)
+#define NI_USUAL_PFI_SELECT(x)\
+	({typeof(x) x_ = (x); (x_ < 10) ? (0x1 + x_) : (0xb + x_); })
+#define NI_USUAL_RTSI_SELECT(x)\
+	({typeof(x) x_ = (x); (x_ < 7) ? (0xb + x_) : 0x1b; })
 
 /*
  * mode bits for NI general-purpose counters, set with
-- 
2.23.0



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