C # Unsafe code (1)

The main reference is C # Language specification Version 3.0.

Introduction

C # is the main development language on the. NET platform, and unlike the classic C + +, the code written by C # is managed code, and the GC manages the memory, eliminating the new/delete annoyance. However, C # provides unsafe code for certain specific requirements, such as the underlying operating system interface, access to memory-mapped devices, or implementation of time-demanding algorithms.

Unsafe context

Unsafe code can only be written in an unsafe context.

You can use the unsafe modifier to modify:

class, struct, interface, or delegate

field, method, property, event, indexer, operator, instance constructor, destructor, or static constructor

unsafe-statement-block

Type of pointer

In an unsafe context, the pointer type is the same as a reference type or a value type. However, pointer types can be used in typeof outside the unsafe context, although it is not safe to do so.

Type t = typeof (int32*); the return is system.int32*.

Pointer types are represented by unmanaged types or void plus *.

pointer-type:
unmanaged-type　　 *
void　　 *

unmanaged-type:
type

The pointer type before * is called the reference type of the pointer type. It indicates the type of variable that the value of the pointer variable points to.

An unmanaged type is not a reference type and contains no members of any nested reference type.

An unmanaged type is one of the following:

sbyte, Byte, short, ushort, int, uint, long, ulong, char, float, double, decimal, or bool.

· Any enum-type.

· Any pointer-type.

· Any user-defined struct-type that contains fields of unmanaged-types.

Example:

Example	Description
byte*	Pointer to byte
char*	Pointer to Char
int**	Pointer to pointer to int
Int*[]	Single-dimensional array of pointers to int
void*	Pointer to unknown type