From: Denis Vlasenko <vda@ilport.com.ua>
To: Neil Brown <neilb@suse.de>
Subject: Re: typedefs and structs [was Re: [PATCH 16/42]: PCI:  PCI Error reporting callbacks]
Date: Fri, 16 Dec 2005 15:09:01 +0200
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Cc: Steven Rostedt <rostedt@goodmis.org>, linas <linas@austin.ibm.com>,
       linux-kernel@vger.kernel.org, bluesmoke-devel@lists.sourceforge.net,
       linux-pci@atrey.karlin.mff.cuni.cz, johnrose@austin.ibm.com,
       linuxppc64-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>,
       Greg KH <greg@kroah.com>
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On Tuesday 08 November 2005 03:18, Neil Brown wrote:
> On Monday November 7, rostedt@goodmis.org wrote:
> > 
> > This was for the simple reason, too many developers were passing
> > structures by value instead of by reference, just because they were
> > using a type that they didn't realize was a structure. And to make
> > things worse, these structures started to get bigger.
> > 
> 
> Another reason  for not using typedefs is that if you do, and you want
> to refer to the structure in some other include file, you have to
> #include the include file that devices the structure.
> If you don't use typedefs, you can just say:
> 
>    struct foo;

Forward decl for typedef works too:

typedef struct foo foo_t;

is ok even before struct foo is defined. Not sure that standards
allow thing, but gcc does.

> and the compiler will happily wait for the complete definition later
> (providing it doesn't need the size in the meanwhile). 
> So avoiding typedef means that you can sometimes avoid excess
> #includes, which means faster compiling.
--
vda
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