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Re: [avr-gcc-list] Best practice for external variable (newbie-ish quest
From: |
Joerg Wunsch |
Subject: |
Re: [avr-gcc-list] Best practice for external variable (newbie-ish question) |
Date: |
Sun, 20 Nov 2005 08:16:59 +0100 (MET) |
Matthew Smith <address@hidden> wrote:
> volatile uint8_t foo;
> extern uint8_t foo;
Note that they don't match. The extern declaration is missing the
"volatile" keyword. Keep in mind that volatile is nothing like a
memory allocation attribute or such that, once stuck onto a variable,
would be accessible to anyone using that variable. Instead, it is a
so-called type qualifier, something that's purely intented for the
compiler to adjust its compilation strategy. Thus, it must be
guaranteed that each part of the compilation knows about that
qualifier.
As Russell already mentioned, the best way to maintain that is by
placing a single declaration of the variable into a central header
file that is included from all source files.
--
cheers, J"org .-.-. --... ...-- -.. . DL8DTL
http://www.sax.de/~joerg/ NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)
- [avr-gcc-list] Best practice for external variable (newbie-ish question), Matthew Smith, 2005/11/19
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), Russell Shaw, 2005/11/19
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), Russell Shaw, 2005/11/19
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question),
Joerg Wunsch <=
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), David Kelly, 2005/11/20
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), Matthew Smith, 2005/11/20
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), David Kelly, 2005/11/20
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), Matthew Smith, 2005/11/20
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), Matthew Smith, 2005/11/21
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), Joerg Wunsch, 2005/11/22
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), Matthew Smith, 2005/11/22
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), Joerg Wunsch, 2005/11/22
- Re: [avr-gcc-list] Best practice for external variable (newbie-ish question), Russell Shaw, 2005/11/20