Programming in the .NET Environment

Unsafe Code

C# allows the user to use a limited version of “inline C” to write pointer-based code.

To safely use pointers in a garbage-collected (GC) environment, there needs to be a mechanism to prevent GC-tracked objects from being relocated by the garbage collector. The runtime environment allows objects to be pinned in place, then exposed in C# in a declarative manner using the fixed statement. The example in Listing B.1 uses an unsafe context to sum up the bytes in a byte array.

Listing B.1.

static unsafe int DoSum(byte[] byteBuffer) { int length = byteBuffer.Length; int sum = 0; fixed (byte* pBuffer = byteBuffer) { byte* pCurrent = pBuffer; while (pCurrent < pBuffer + length) { sum += *pCurrent; pCurrent++; } } return sum; }

The fixed ...