Date: Mon, 14 Dec 1998 23:46:30 -0500 (EST) From: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> To: Mike Smith <mike@smith.net.au> Cc: Eivind Eklund <eivind@yes.no>, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/i386/isa labpc.c Message-ID: <199812150446.XAA19758@khavrinen.lcs.mit.edu> In-Reply-To: <199812150420.UAA02573@dingo.cdrom.com> References: <19981215045111.B46780@follo.net> <199812150420.UAA02573@dingo.cdrom.com>
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<<On Mon, 14 Dec 1998 20:20:01 -0800, Mike Smith <mike@smith.net.au> said:
> struct foo {
> int a;
> void *b;
> };
> #define STRUCT_FOO_INIT {0, NULL}
Much better to write this:
static struct foo STRUCT_FOO_INIT;
The Standard specifies that all objects with static lifetime are
initialized AS IF each element were explicitly initialized to the
integral constant zero. This means in particular that all pointers
are initialized to a null pointer value, and all floating-point
objects are initialized to the appropriate representation of the value
zero. (Some values of GCC will generate suboptimal code for automatic
structure initialization.)
I often attempt use the following coding style:
static const struct something null_something;
int
myfunc(args)
{
struct something my_something = null_something;
/* do stuff with it... */
}
However, from an efficiency standpoint, bzero will do just as well and
is probably faster.
-GAWollman
--
Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same
wollman@lcs.mit.edu | O Siem / The fires of freedom
Opinions not those of| Dance in the burning flame
MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick
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