In my C# source code I may have declared integers as:
int i = 5;
or
Int32 i = 5;
In the currently prevalent 32bit world they are equivalent. However, as we move into a 64bit world am I correct in saying that the following will become the same?
int i = 5;
Int64 i = 5;
No. The C# specification rigidly defines that int is an alias for System.Int32 with exactly 32 bits. Changing this would be a major breaking change.
yes, as jon said, and unlike the 'C/C++ world', Java and C# aren't dependent of the system they're running on. They have strictly defined lengths for byte/short/int/long and single/double precision floats, equal on every system.
No matter whether you're using the 32-bit version or 64-bit version of the CLR, in C# an int will always mean System.Int32 and long will always mean System.Int64.
int is currently always synonymous with Int32 on all platforms.
It's very unlikely that Microsoft will change that in the near future, as it will break lots of existing code that assumes int is 32-bits.
The int keyword in C# is defined as an alias for the System.Int32 type and this is (judging by the name) meant to be a 32-bit integer. To the specification:
CLI specification section 8.2.2 (Built-in value and reference types) has a table with the following:
System.Int32- Signed 32-bit integerC# specification section 8.2.1 (Predefined types) has a similar table:
int- 32-bit signed integral type
This guarantees that both System.Int32 in CLR and int in C# will always be 32-bit.
My best guess is that it will be changed right around the same time that Internet Explorer X is fully standards compliant.
I think what you may be confused by is that int is an alias for Int32 so it will always be 4 bytes, but IntPtr is suppose to match the word size of the CPU architecture so it will be 4 bytes on a 32-bit system and 8 bytes on a 64-bit system.
Will sizeof(testInt) ever be 8?
No, sizeof(testInt) is an error. testInt is a local variable. The sizeof operator requires a type as its argument. This will never be 8 because it will always be an error.
VS2010 compiles a c# managed integer as 4 bytes, even on a 64 bit machine.
Correct. I note that section 18.5.8 of the C# specification defines sizeof(int) as being the compile-time constant 4. That is, when you say sizeof(int) the compiler simply replaces that with 4; it is just as if you'd said "4" in the source code.
Does anyone know if/when the time will come that a standard "int" in C# will be 64 bits?
Never. Section 4.1.4 of the C# specification states that "int" is a synonym for "System.Int32".
If what you want is a "pointer-sized integer" then use IntPtr. An IntPtr changes its size on different architectures.