Common Intermediate Language - Example

Example

Below is a basic Hello, World program written in CIL. It will display the string "Hello, world!".

.assembly Hello {} .assembly extern mscorlib {} .method static void Main { .entrypoint .maxstack 1 ldstr "Hello, world!" call void System.Console::WriteLine(string) ret }

The following code is more complex in number of opcodes.

This code can also be compared with the corresponding code in the article about Java bytecode.

static void Main(string args) { for (int i = 2; i < 1000; i++) { for (int j = 2; j < i; j++) { if (i % j == 0) goto outer; } Console.WriteLine(i); outer: } }

In CIL syntax it looks like this:

.method private hidebysig static void Main(string args) cil managed { .entrypoint .maxstack 2 .locals init (int32 V_0, int32 V_1) ldc.i4.2 stloc.0 br.s IL_001f IL_0004: ldc.i4.2 stloc.1 br.s IL_0011 IL_0008: ldloc.0 ldloc.1 rem brfalse.s IL_001b ldloc.1 ldc.i4.1 add stloc.1 IL_0011: ldloc.1 ldloc.0 blt.s IL_0008 ldloc.0 call void System.Console::WriteLine(int32) IL_001b: ldloc.0 ldc.i4.1 add stloc.0 IL_001f: ldloc.0 ldc.i4 0x3e8 blt.s IL_0004 ret }

This is just a representation of how CIL looks like near VM-level. When compiled the methods are stored in tables and the instructions are stored as bytes inside the assembly, which is a Portable Executable (PE).