[PATCH 1/6] rtc: generic: allow building on all architectures
From: Andreas Schwab <hidden>
Date: 2016-03-02 09:28:55
Also in:
linux-m68k, linux-rtc, linux-sh, linuxppc-dev, lkml
Possibly related (same subject, not in this thread)
- 2016-03-02 · Re: [PATCH 1/6] rtc: generic: allow building on all architectures · Arnd Bergmann <arnd@arndb.de>
- 2016-03-02 · Re: [PATCH 1/6] rtc: generic: allow building on all architectures · Geert Uytterhoeven <geert@linux-m68k.org>
- 2016-03-01 · [PATCH 1/6] rtc: generic: allow building on all architectures · Arnd Bergmann <arnd@arndb.de>
Geert Uytterhoeven [off-list ref] writes:
quoted
+#else +#define generic_rtc_ops *(struct rtc_class_ops*)NULL +#endif static int __init generic_rtc_probe(struct platform_device *dev) { struct rtc_device *rtc; + const struct rtc_class_ops *ops; + + ops = dev_get_platdata(&dev->dev); + if (!ops) + ops = &generic_rtc_ops;I hope no compiler version treats "&*(struct rtc_class_ops*)NULL" as undefined behavior?
Yes, that is guaranteed, the operations cancel each other (6.5.3.2#3: If the operand is the result of a unary * operator, neither that operator nor the & operator is evaluated and the result is as if both were omitted). Andreas. -- Andreas Schwab, schwab at linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different."