Managed code
Encyclopedia
Managed code is a term coined by Microsoft to identify computer program code
that requires and will only execute under the "management" of a Common Language Runtime
virtual machine
(resulting in Bytecode
).
This disambiguation is prevalent and only relevant when developing applications that interact with the .NET Framework
or other Common Language Runtime
implementations, like Mono
. Since some of the classic programming languages have been ported into the Common Language Runtime
, the differentiation is needed to identify "managed" code, especially in a mixed setup. In this same context programmers also refer to code that doesn't depend on the Common Language Runtime
as unmanaged.
Microsoft's Visual C++ development environment can produce both managed code (running under the .NET Common Language Runtime) or compiled binaries, running directly on the Windows platform with the help of its C++ Runtime Library.
Benefits of using managed code include programmer convenience (by increasing the level of abstraction, creating smaller models) and enhanced security guarantees, depending on the platform (including the VM implementation). There are many historical examples of code running on virtual machines, such as UCSD Pascal
utilizing p-code
and the Inferno operating system
from Bell Labs
utilizing the Dis virtual machine
. Java popularized this approach with its bytecode
executed by the Java Virtual Machine
.
Another source of confusion was created when Microsoft started connecting the .NET Framework with C++, and the selection on how to name the Managed Extensions for C++
, it was first named Managed C++ and then renamed to C++/CLI
. Bjarne Stroustrup
, creator of the C++ programming language and member of the C++ standards committee even commented on this issue, "On the difficult and controversial question of what the CLI binding/extensions to C++ is to be called, I prefer C++/CLI as a shorthand for "The CLI extensions to ISO C++". Keeping C++ as part of the name reminds people what is the base language and will help keep C++ a proper subset of C++ with the C++/CLI extensions."
Source code
In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...
that requires and will only execute under the "management" of a Common Language Runtime
Common Language Runtime
The Common Language Runtime is the virtual machine component of Microsoft's .NET framework and is responsible for managing the execution of .NET programs. In a process known as just-in-time compilation, the CLR compiles the intermediate language code known as CIL into the machine instructions...
virtual machine
Virtual machine
A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...
(resulting in Bytecode
Bytecode
Bytecode, also known as p-code , is a term which has been used to denote various forms of instruction sets designed for efficient execution by a software interpreter as well as being suitable for further compilation into machine code...
).
This disambiguation is prevalent and only relevant when developing applications that interact with the .NET Framework
.NET Framework
The .NET Framework is a software framework that runs primarily on Microsoft Windows. It includes a large library and supports several programming languages which allows language interoperability...
or other Common Language Runtime
Common Language Runtime
The Common Language Runtime is the virtual machine component of Microsoft's .NET framework and is responsible for managing the execution of .NET programs. In a process known as just-in-time compilation, the CLR compiles the intermediate language code known as CIL into the machine instructions...
implementations, like Mono
Mono (software)
Mono, pronounced , is a free and open source project led by Xamarin to create an Ecma standard compliant .NET-compatible set of tools including, among others, a C# compiler and a Common Language Runtime....
. Since some of the classic programming languages have been ported into the Common Language Runtime
Common Language Runtime
The Common Language Runtime is the virtual machine component of Microsoft's .NET framework and is responsible for managing the execution of .NET programs. In a process known as just-in-time compilation, the CLR compiles the intermediate language code known as CIL into the machine instructions...
, the differentiation is needed to identify "managed" code, especially in a mixed setup. In this same context programmers also refer to code that doesn't depend on the Common Language Runtime
Common Language Runtime
The Common Language Runtime is the virtual machine component of Microsoft's .NET framework and is responsible for managing the execution of .NET programs. In a process known as just-in-time compilation, the CLR compiles the intermediate language code known as CIL into the machine instructions...
as unmanaged.
Microsoft's Visual C++ development environment can produce both managed code (running under the .NET Common Language Runtime) or compiled binaries, running directly on the Windows platform with the help of its C++ Runtime Library.
Benefits of using managed code include programmer convenience (by increasing the level of abstraction, creating smaller models) and enhanced security guarantees, depending on the platform (including the VM implementation). There are many historical examples of code running on virtual machines, such as UCSD Pascal
UCSD Pascal
UCSD Pascal was a Pascal programming language system that ran on the UCSD p-System, a portable, highly machine-independent operating system. UCSD Pascal was first released in 1978...
utilizing p-code
P-Code machine
In computer programming, a p-code machine, or portable code machine is a virtual machine designed to execute p-code...
and the Inferno operating system
Inferno (operating system)
Inferno is a distributed operating system started at Bell Labs, but is now developed and maintained by Vita Nuova Holdings as free software. Inferno was based on the experience gained with Plan 9 from Bell Labs, and the further research of Bell Labs into operating systems, languages, on-the-fly...
from Bell Labs
Bell Labs
Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...
utilizing the Dis virtual machine
Dis virtual machine
The Dis virtual machine is the execution environment for application code in the Inferno operating system. Its design is based on a register machine, closely modeling CISC-like architectures on which it runs...
. Java popularized this approach with its bytecode
Java bytecode
Java bytecode is the form of instructions that the Java virtual machine executes. Each bytecode opcode is one byte in length, although some require parameters, resulting in some multi-byte instructions. Not all of the possible 256 opcodes are used. 51 are reserved for future use...
executed by the Java Virtual Machine
Java Virtual Machine
A Java virtual machine is a virtual machine capable of executing Java bytecode. It is the code execution component of the Java software platform. Sun Microsystems stated that there are over 4.5 billion JVM-enabled devices.-Overview:...
.
Another source of confusion was created when Microsoft started connecting the .NET Framework with C++, and the selection on how to name the Managed Extensions for C++
Managed Extensions for C++
Managed Extensions for C++ or just Managed C++ is a now deprecated Microsoft set of deviations from C++, including grammatical and syntactic extensions, keywords and attributes, to bring the C++ syntax and language to the .NET Framework...
, it was first named Managed C++ and then renamed to C++/CLI
C++/CLI
C++/CLI is Microsoft's language specification intended to supersede Managed Extensions for C++. It is a complete revision that aims to simplify the older Managed C++ syntax . C++/CLI is standardized by Ecma as ECMA-372...
. Bjarne Stroustrup
Bjarne Stroustrup
Bjarne Stroustrup ; born December 30, 1950 in Århus, Denmark) is a Danish computer scientist, most notable for the creation and the development of the widely used C++ programming language...
, creator of the C++ programming language and member of the C++ standards committee even commented on this issue, "On the difficult and controversial question of what the CLI binding/extensions to C++ is to be called, I prefer C++/CLI as a shorthand for "The CLI extensions to ISO C++". Keeping C++ as part of the name reminds people what is the base language and will help keep C++ a proper subset of C++ with the C++/CLI extensions."