__int8, __int16, __int32, __int64
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__int8, __int16, __int32, __int64

Microsoft C/C++ features support for sized integer types. You can declare 8-, 16-, 32-, or 64-bit integer variables by using the __intn type specifier, where n is 8, 16, 32, or 64.

The following example declares one variable for each of these types of sized integers:

__int8 nSmall;      // Declares 8-bit integer
__int16 nMedium;    // Declares 16-bit integer
__int32 nLarge;     // Declares 32-bit integer
__int64 nHuge;      // Declares 64-bit integer

The types __int8, __int16, and __int32 are synonyms for the ANSI types that have the same size, and are useful for writing portable code that behaves identically across multiple platforms. The __int8 data type is synonymous with type char, __int16 is synonymous with type short, and __int32 is synonymous with type int. The __int64 type has no ANSI equivalent.

The following sample shows that an __intxx parameter will be promoted to int:

// sized_int_types.cpp

#include <stdio.h>

void func(int i) {
    printf_s("%s\n", __FUNCTION__);

int main()
    __int8 i8 = 100;
    func(i8);   // no void func(__int8 i8) function
                // __int8 will be promoted to int


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