From: "J.A. Magallon" <jamagallon@able.es>
To: Lista Linux-Kernel <linux-kernel@vger.kernel.org>
Subject: [2.4] gcc3 warns about type-punned pointers ?
Date: Fri, 29 Aug 2003 00:35:11 +0200 [thread overview]
Message-ID: <20030828223511.GA23528@werewolf.able.es> (raw)
Hi all...
gcc3 gives this warning when using the __set_64bit_var function:
/usr/src/linux/include/asm/system.h:190: warning: dereferencing type-punned pointer will break strict-aliasing rules
Is it a potential problem ?
This seems to cure it:
--- linux-2.4.22-jam1m/include/asm-i386/system.h.orig 2003-08-29 00:26:41.000000000 +0200
+++ linux-2.4.22-jam1m/include/asm-i386/system.h 2003-08-29 00:26:55.000000000 +0200
@@ -181,8 +181,8 @@
{
__set_64bit(ptr,(unsigned int)(value), (unsigned int)((value)>>32ULL));
}
-#define ll_low(x) *(((unsigned int*)&(x))+0)
-#define ll_high(x) *(((unsigned int*)&(x))+1)
+#define ll_low(x) *(((unsigned int*)(void*)&(x))+0)
+#define ll_high(x) *(((unsigned int*)(void*)&(x))+1)
static inline void __set_64bit_var (unsigned long long *ptr,
unsigned long long value)
A collateral question: why is the reason for this function ?
long long assignments are not atomic in gcc ?
TIA
--
J.A. Magallon <jamagallon@able.es> \ Software is like sex:
werewolf.able.es \ It's better when it's free
Mandrake Linux release 9.2 (Cooker) for i586
Linux 2.4.22-jam1m (gcc 3.3.1 (Mandrake Linux 9.2 3.3.1-1mdk))
next reply other threads:[~2003-08-28 22:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-28 22:35 J.A. Magallon [this message]
2003-08-29 15:24 ` [2.4] gcc3 warns about type-punned pointers ? Antonio Vargas
2003-08-29 18:48 ` J.A. Magallon
2003-08-29 19:41 ` Richard B. Johnson
2003-08-30 6:27 ` Antonio Vargas
2003-08-30 9:56 ` Willy Tarreau
2003-08-30 11:31 ` Jamie Lokier
2003-08-30 2:37 ` insecure
2003-08-30 12:33 ` Mikulas Patocka
2003-08-30 13:09 ` Gabriel Paubert
2003-08-30 23:27 ` insecure
2003-08-31 1:27 ` J.A. Magallon
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