Which runtime library to use

Instead the compiler often uses compiler-specific auxiliary functions in the runtime library that are mostly not accessible to application programmers. Depending on the compiler manufacturer, the runtime library will sometimes also contain the standard library of the respective compiler or be contained in it.

Also some functions that can be performed only or are more efficient or accurate at runtime are implemented in the runtime library, e. For this reason, some programming bugs are not discovered until the program is tested in a "live" environment with real data, despite sophisticated compile-time checking and pre-release testing.

In this case, the end user may encounter a runtime error message. Usually the runtime library realizes many functions by accessing the operating system. Many programming languages have built-in functions that do not necessarily have to be realized in the compiler, but can be implemented in the runtime library. So the border between runtime library and standard library is up to the compiler manufacturer. Therefore a runtime library is always compiler-specific and platform-specific.

The concept of a runtime library should not be confused with an ordinary program library like that created by an application programmer or delivered by a third party or a dynamic library, meaning a program library linked at run time. For example, the programming language C requires only a minimal runtime library commonly called crt0 but defines a large standard library called C standard library that each implementation has to deliver.

I just asked this myself and was hurting my brain for some hours. Still did not find anything that really makes a point.

A runtime library is a collection of software programs used at program run time to provide one or more native program functions or services. The runtime library enables a software program to be executed with its complete functionality and scope by providing add-on program resources that are essential for the primary program. Typically, it consists of many different programs or functions that are commonly used in various programs.

The runtime library is invoked in all programs. At program runtime, the respective runtime library or function is loaded in the memory until the primary program has finished execution or no longer requires that function. A dynamic link library is a type of runtime library that dynamically links with programs on its runtime or execution. Share this Term.

If you know that the dynamic runtime is already available on your target system, however, linking to the static runtime will probably make your distribution larger. Second, by linking with the static runtime, you avoid versioning problems that can occur when several different versions of a dynamic library exist on a single system. Linking with a dynamic runtime library is also attractive, however. This is because a very effective way to organize an application is as a collection of dynamic libraries.

For one thing, it allows parts of the application to be updated without requiring the entire application to be reinstalled. Furthermore, applications can sometimes improve their performance significantly by taking advantage of the delay-loading feature of DLLs on Windows. But because all components of an application should use a single variant of the runtime library, once an application makes use of a single dynamic library, all the component of that application should use dynamically linked runtimes.

As a result, using a dynamically linked runtime makes your application easier to modularize. I recommend that you choose dynamic linking most of the time. As mentioned earlier, however, sometimes static linking is more appropriate.

In that case, a common solution is to provide multiple variants of your library, linked against different variants of the runtime libraries. Recipe 1. Header files available during compilation, that contain inline implementations e.

Windows CreateFile for fstreams. Using dynamic libraries requires the respective runtime to be installed on the target platform, but using them it reduces the size of your executable and your already-installed application benefits from updates to the runtime. As noted, this is implementation-dependent. There might be any number of additional files such as data files, configuration files, debug symbols, icons, etc. Another important aspect here: the language provides an abstraction of the target platform, the abstraction layer is implemented in the runtime.

Code from static libraries are put in your executable at compile time The Linker does this. So this code can bloat your executable but it is on every computer the same code. When you use dynamic libraries. When executing your binary, the OS loads the libraries in the address space of your executable and resolves the links. So your executable is smaller and the library can be used by many programs. When there are bugs in this library, this has to replaced only once for every program.

But this only works, if the interface of the library is only changed with care, otherwise - welcome to DLL hell. How are we doing? Please help us improve Stack Overflow. Take our short survey.