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From: lium@i-net.com.cn
To: gcc-help@gcc.gnu.org <gcc-help@gcc.gnu.org>,
	gcc-help-help@gcc.gnu.org <gcc-help-help@gcc.gnu.org>
Subject: help: sizeof(struct)
Date: Mon, 15 Jul 2002 19:49:00 -0000	[thread overview]
Message-ID: <GZBMHQ00.EL5@mail.i-net.com.cn> (raw)

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Hi,
	
	there is a struct like following:
	
	struct test {
		unsigned char a;
		unsigned int b;
		unsigned char c;
	}
	my target machine is ARM7TDMI, my gcc version is: "gcc version 3.0". when i use sizeof(struct test), it return 0xc. if i add 'packed' attribute, sizeof return 6. but i need the sizeof macro return 9. 
	
    the follow is memory layout:                    
                                                    
Normal: +---+---+---+---+  Packed: +---+---+---+---+
        |///|///|///|///|          |///|///|///|///|
        +---+---+---+---+          +---+---+---+---+
        | a |   |   |   |          | a | b | b | b |
        +---+---+---+---+          +---+---+---+---+
        | b | b | b | b |          | b | c |///|///|
        +---+---+---+---+          +---+---+---+---+
        | c |   |   |   |          |///|///|///|///|
        +---+---+---+---+          +---+---+---+---+
                                                    
Wanted: +---+---+---+---+                           
        |///|///|///|///|                           
        +---+---+---+---+                           
        | a |   |   |   |                           
        +---+---+---+---+                           
        | b | b | b | b |                           
        +---+---+---+---+                           
        | c |///|///|///|                           
        +---+---+---+---+         

	would you please tell me which compiling option can do so.

	                 



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             reply	other threads:[~2002-07-16  2:49 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-07-15 19:49 lium [this message]
2002-07-16  2:19 ` Claudio Bley

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