Re: [boost] int vs int32_t [was: Serialiization Review repost with consistent quoting]

From: Kevin Lynch (krlynch_at_[hidden])
Date: 2002-11-27 12:05:30

Michael Walter wrote:

>>If a library user wants his archives to be portable he has to use
>>int8_t, int16_t, etc.. 

I don't remember seeing this pointed out, so forgive me if I just missed 
it or am just stating the obvious, but:

These types are technically NOT portable, in two ways:

1) They are not defined by ISO C++ ... although they are required by 
POSIX 1g, and are optional types in ISO C, C++ compilers are not 
required to support them.

2) Although both POSIX and C99 define them to be 2's complement integers 
with the appropriate number of bits, neither standard sets a requirement 
on byte ordering within the multibyte types.  Thus, even if a platform 
supports them (say, the BSD family), the binary form of the integers is 
not portable.

So, while use of them may lead to a MORE portable C++ interface, they 
won't directly lead to a portable binary serialization format (although 
you can clearly fix that problem in platform specific byte reordering code).

-- 
-------------------------------------------------------------------------------
Kevin Lynch				voice:	[phone]
Physics Department			Fax: [phone]
Boston University			office:	 PRB-361
590 Commonwealth Ave.			e-mail:	 krlynch_at_[hidden]
Boston, MA 02215 USA			http://budoe.bu.edu/~krlynch
-------------------------------------------------------------------------------