-----Original Message----- From: Timur Tabi [mailto:timur@freescale.com] Sent: Thursday, April 09, 2009 2:28 AM To: Premi, Sanjeev Cc: Jerry Van Baren; U-Boot-Users ML; Kumar Gala Subject: Re: [U-Boot] use of C99
Premi, Sanjeev wrote:
One of the biggest problem is uncontrolled variable definitions that gets even nasty when variables have same names with different types; though under different set of #ifdefs. Quite possible for commonly used variable names - i, ptr, tmp, etc.
Then let's just say that if you're going to define a variable in the middle of a function, it can't have the same name as another variable in that function.
I feel, here, ifdefs provide a false sense of 'enclosure'
with possibility
of frequent breaches - in code (while implementing) and in
simple reading
(for understanding).
Sorry, I don't understand what you're talking about. The #ifdefs are used to enable feature-specific code on platforms that have that feature.
I was referring to declaring variable within #ifdefs with belief that use will be contained.
e.g. #ifdef CONFIG_COOL_FEATURE int i; int* ptr ; ... ... #endif
... ... 2 screenful down; in same function... ...
#ifdef CONFIG_HOT_FEATURE u32 i; void* ptr; ... ... #endif
Maybe for sometime the usage seems contained. Until someone decides to have both the COOL and HOT feature.
~sanjeev
-- Timur Tabi Linux kernel developer at Freescale