Forcing certain sized ints and floats
what happens if you compile the code on a 64bit platform
can you still gaurentee the sizes then?
can you still gaurentee the sizes then?
I believe the official word from Microsoft was that an int was going to stay 32-bit and that long long will be used for 64-bit ints in Visual Studio. (This could possibly change if the C++ standard changes to officially incorporate 64-bit variables).
"if the C++ standard changes to officially incorporate 64-bit variables"
The C++ Standard does not put many restrictions on the sizes of variables. I don't even think that it assumes an 8 bit byte. You could probably have a 10 bit char and a 50 bit int. So C++ has all of the 64 bit support that it needs. Other than a few simple rules (like int must be bigger than a char, and it must also be an even multiple, so you could have sizeof(int)==sizeof(char) )
Personally I think that int, float and char should be templates with typedefs supplied by the vendor.
so these two would be the same type:
integer<32,signed> i;
int j;
you could do this:
integer<64,unsigned> u;
The C++ Standard does not put many restrictions on the sizes of variables. I don't even think that it assumes an 8 bit byte. You could probably have a 10 bit char and a 50 bit int. So C++ has all of the 64 bit support that it needs. Other than a few simple rules (like int must be bigger than a char, and it must also be an even multiple, so you could have sizeof(int)==sizeof(char) )
Personally I think that int, float and char should be templates with typedefs supplied by the vendor.
so these two would be the same type:
integer<32,signed> i;
int j;
you could do this:
integer<64,unsigned> u;
For gcc, you can include the header file stdint.h, it includes types such as int32_t, uint32_t, uint8_t, etc. However, if you can't/don't want to do that, all you have to really do is declare your types in the one header file with #ifdefs for each platform you plan to compile on. Later on, if you port to other platforms, just add to that header file.
Quote:Original post by Glak
Personally I think that int, float and char should be templates with typedefs supplied by the vendor.
so these two would be the same type:
integer<32,signed> i;
int j;
you could do this:
integer<64,unsigned> u;
Seems like it shouldn't be too hard to do. Provide a basic 'big-int' type functionality by default, and provide explicit instances for the common values [16/32/64]. I might dabble with that over the next couple days if I get bored, sounds like an interesting way to spend an afternoon.
CM
Quote:Original post by colinisinhere
so, for sure, gcc uses 16 bits shorts, 32 bit ints? No matter what?
Nope. GCC compiles for far more than just the i386 architecture.
Quote:Original post by Glak
The C++ Standard does not put many restrictions on the sizes of variables. I don't even think that it assumes an 8 bit byte. You could probably have a 10 bit char and a 50 bit int. So C++ has all of the 64 bit support that it needs. Other than a few simple rules (like int must be bigger than a char, and it must also be an even multiple, so you could have sizeof(int)==sizeof(char) )
The standard does not in fact define a char as an 8-bit byte. It's defined as the smallest unit of addressable memory. sizeof(char) must be equal to 1. The x86 architecture happens to address 8-bit bytes. If C++ were implemented on the Symbolics 3600 series, it would have a 36-bit char.
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