From -1040010702452402558 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,738ae3371beb3408 X-Google-Attributes: gidf78e5,public From: Francis Glassborow Subject: Re: portable method of determining endianness byte order. Date: 1999/11/19 Message-ID: #1/1 X-Deja-AN: 550689446 Approved: stephen.clamage@sun.com (comp.std.c++) References: <38329967.470B6CED@hqs.mid.gmeds.com> X-UID: 0000000001 X-Status: $$$T Organization: Southfield Microcomputer SS Mime-Version: 1.0 Reply-To: Francis Glassborow Newsgroups: comp.std.c++ Originator: clamage@taumet In article <38329967.470B6CED@hqs.mid.gmeds.com>, Pukalo Boyd 810-492-3661 writes >I have been trying to find a portable method of determining the >endianness byte order at compile time >to produce code that will work properly on both windows and unix >machines. I have searched the documentation >i have ( the books on the C Standard Library and the C++ Standard >Library) and havent found anything. Please help. Any pointers or >suggestions would be very helpful. Thanks. Having checked that the executing system has the same number of bits/byte that you expect, that it has the same size int (long, float etc) you could try something such as: union { int sample; char bytes[sizeof(int)]; } test; if(sizeof(int) == 2){ test.sample = Ox0102; if (test.bytes[0] == 1) ... and so on. but there are so many variations that it hardly seems worth the effort. Francis Glassborow Journal Editor, Association of C & C++ Users 64 Southfield Rd Oxford OX4 1PA +44(0)1865 246490 All opinions are mine and do not represent those of any organisation [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://reality.sgi.com/austern_mti/std-c++/faq.html ]