Primitive types are small value types that are copied to the stack (or a CPU register) when you use them as function parameters or return values. You don't need to pin or otherwise manage the lifespan of primitive types when calling unmanaged functions.

C# has different names for many primitive types compared to C and other languages. Refer to Platform invoke data types for a list of the unmanaged C language types that correspond to the managed C# types.

The following table shows the C type that each C# type marshals to by default. Default marshalling is a starting point, not a guarantee: it can vary by platform and by context (parameter, return value, or struct field). For example, marshals to a 4-byte value by default, and marshals according to the of the call. Use MarshalAsAttribute to control the exact representation when the default isn't what you need.

Some examples include:

int32_t

<stdint.h>

int

long

long