Additional concerns when compiling for x64

I know that the additional consideratiosn when compiling for x64 is that some data types, like ints, can hold larger values. Are there any concerns?

VS2010, released a few days ago, can support compiling for x64 and x32, just like VS2008. The app is x32/86 only. I keep thinking that the app needs to be 64 bi开发者_高级运维t however. What am I missing? Obviously this is not the case.

Thanks

Regarding VS2010 (IDE & plugins) not being a 64 bit app, i believe there are 2 main reasons -

1. If the app is 64 bit, then pointers and ints would consume twice more memory which would be worse for most folks.

2. Parts of Visual Studio are already ported to .NET. It would be simpler to finish porting rest of it to .NET rather than port C/C++ code to x64.

http://blogs.msdn.com/ricom/archive/2009/06/10/visual-studio-why-is-there-no-64-bit-version.aspx

Reasons to build for x86-64:

• your app needs > 4 GB address space

• your app is performance-critical and could benefit from ~30% performance improvement due to increased size and number of registers

If neither of the above applies then there is no compelling reason to make an app 64-bit.