Microsoft Windows library files

Source: Wikipedia, the free encyclopedia.

The

shared libraries known as "dynamic-link libraries", which are code libraries that can be used by multiple processes while only one copy is loaded into memory
. This article provides an overview of the core libraries that are included with every modern Windows installation, on top of which most Windows applications are built.

Internal components

HAL.DLL is a kernel-mode library file and it cannot be used by any user-mode program. NTDLL.DLL is only used by some programs, but it is a dependency of most Win32 libraries used by programs.

HAL.DLL

The Hardware Abstraction Layer in the architecture of Windows NT

The Windows

Hardware Abstraction Layer (HAL) is implemented in hal.dll.[1] The HAL implements a number of functions that are implemented in different ways by different hardware platforms, which in this context, refers mostly to the chipset. Other components in the operating system
can then call these functions in the same way on all platforms, without regard for the actual implementation.

For example, responding to an interrupt is quite different on a machine with an Advanced Programmable Interrupt Controller (APIC) than on one without. The HAL provides a single function for this purpose that works with all kinds of interrupts by various chipsets, so that other components need not be concerned with the differences.

The HAL is loaded into kernel address space and runs in kernel mode, so routines in the HAL cannot be called directly by applications, and no user mode APIs correspond directly to HAL routines. Instead, the HAL provides services primarily to the Windows executive and kernel and to kernel mode device drivers. Although drivers for most hardware are contained in other files, commonly of file type .sys, a few core drivers are compiled into hal.dll.

Kernel mode device drivers for devices on buses such as

CPU
architecture, and the driver source file can be portable across all architectures.

On

hyperthreading CPU, all count as "processors" for this purpose.) On x86-64 and Itanium
platforms there is just one possible hal.dll for each CPU architecture. On Windows 8 and later, the x86 version also only has one HAL.

HAL is merged (or statically linked) into ntoskrnl.exe[2] starting with version 2004 of Windows 10, and the dll only serves as a stub for backwards compatibility.

NTDLL.DLL

NTDLL.DLL exports the Windows

Win32 or other API subsystems. Most of this API is implemented in NTDLL.DLL and at the upper edge of ntoskrnl.exe (and its variants), and the majority of exported symbols within these libraries are prefixed Nt, for example NtDisplayString. Native APIs are also used to implement many of the "kernel APIs" or "base APIs" exported by KERNEL32.DLL.[3][4][5] The large majority of Windows applications do not call NTDLL.DLL directly.[6]

Applications that are

csrss.exe
itself is such an application.

Despite having an ".exe" file extension, native applications cannot be executed by the user (or any program in the Win32 or other subsystems). An example is the autochk.exe binary that runs

csrss.exe
.

Unlike

Win32 applications, native applications instantiate within the Kernel runtime code (ntoskrnl.exe) and so they must have a different entry point (NtProcessStartup, rather than (w)(Win)MainCRTStartup as is found in a Win32 application),[4] obtain their command-line arguments via a pointer to an in-memory structure, manage their own memory using the Rtl heap API, (which the Win32 heap APIs are just wrappers around—no real difference there) and return execution with a call to RtlExitUserProcess (as opposed to ExitProcess). A common library linked with Native applications is nt.lib, which contains startup code for Native applications, similar to how the C runtime provides startup code for Win32 apps.[7]

Though most of the API is undocumented, Native Applications can be built using the Windows Driver Development Kit; many

userspace.[citation needed
]

Win32 API

Further information: Windows API

The libraries in this section each implement various subsets of the Win32 API.

KERNEL32.DLL

KERNEL32.DLL exposes to applications most of the Win32 base APIs, such as

native API, exposed by NTDLL.DLL.[8][failed verification
]

GDI32.DLL

GDI32.DLL exports Graphics Device Interface (GDI) functions that perform primitive drawing functions for output to video displays and printers. It is used, for example, in the XP version of Paint. Applications call GDI functions directly to perform low-level drawing (line, rectangle, ellipse), text output, font management, and similar functions.[8][9]

Initially, GDI supported 16 and 256 color

multiple monitors.[10]

USER32.DLL

Further information: Windows USER

USER32.DLL implements the Windows USER component that creates and manipulates the standard elements of the Windows user interface, such as the desktop, windows, and menus. It thus enables programs to implement a graphical user interface (GUI) that matches the Windows look and feel. Programs call functions from Windows USER to perform operations such as creating and managing windows, receiving window messages (which are mostly user input such as mouse and keyboard events, but also notifications from the operating system), displaying text in a window, and displaying message boxes.

Many of the functions in USER32.DLL call upon GDI functions exported by GDI32.DLL to do the actual rendering of the various elements of the user interface. Some types of programs will also call GDI functions directly to perform lower-level drawing operations within a window previously created via USER32 functions.

COMCTL32.DLL

COMCTL32.DLL implements a wide variety of standard Windows controls, such as File Open, Save, and Save As dialogs, progress bars, and list views. It calls functions from both USER32.DLL and GDI32.DLL to create and manage the windows for these UI elements, place various graphic elements within them, and collect user input.

COMDLG32.DLL

COMDLG32.DLL, the Common Dialog Box Library, implements a wide variety of Windows dialog boxes intended to perform what Microsoft deems 'common application tasks'. Starting with the release of Windows Vista, Microsoft considers the "Open" and "Save as" dialog boxes provided by this library as deprecated and replaced by the 'Common Item Dialog API'.[11]

WS2_32.DLL

WS2_32.DLL implements the Winsock API, which provides TCP/IP networking functions and provides partial, broken compatibility with other network APIs. wsock.dll and wsock32.dll are older versions for Win3.11 and Win95 compatibility.

ADVAPI32.DLL

ADVAPI32.DLL, the Advanced Windows 32 Base API DLL,[12] provides security calls and functions for manipulating the Windows Registry.

NETAPI32.DLL

NETAPI32.DLL provides functions for querying and managing network interfaces.

OLE32.DLL

OLE32.DLL provides the Component Object Model, as well as Object Linking and Embedding.

Other APIs

SHSCRAP.DLL

SHSCRAP.DLL is part of the

Object Packager
to create them. They can then be dragged into another OLE-capable application.

This functionality was removed from Windows Vista (and therefore later versions) to improve security and rid the operating system of generally unused functionality.[14] Scrap (.shs) files have been used by viruses because they can contain a wide variety of files (including executable code), and the file extension is not shown even when "Hide file extensions from known file types" is disabled.[15] The functionality can be restored by copying registry entries and the DLL from a Windows XP system.[16]

WINMM.DLL

WINMM.DLL provides access to the original

WinMM
audio API.

IMM32.DLL

IMM32 is responsible for invoking and interacting with the

Input Method Editor
.

Runtime libraries

MSVCRT.DLL, MSVCP*.DLL and CRTDLL.DLL

MSVCRT.DLL is the

Visual C++ (MSVC)
compiler from version 4.2 to 6.0. It provides programs compiled by these versions of MSVC with most of the standard C library functions. These include string manipulation, memory allocation, C-style input/output calls, and others. MSVCP*.DLL is the corresponding C++ library.

It has shipped with Windows versions since Windows 95 OSR2.5 for use by other Windows components; earlier versions shipped with the CRTDLL.DLL library instead. In older versions of Windows, programs which linked against MSVCRT.DLL were expected to install a compatible copy in the System32 folder, but this contributed to DLL Hell because many installers failed to check the library version against the installed version before replacing it.

Versions of MSVC before 4.0 and from 7.0 to 12.0 used differently named DLLs for each version (MSVCR20.DLL, MSVCR70.DLL, MSVCR71.DLL, MSVCP110.DLL, etc.). Applications are required to install the appropriate version,[17] and Microsoft offers Visual C++ Redistributable packages for this purpose, though Windows typically comes with one version already installed.

This runtime library is used by programs written in Visual C++ and a few other compilers (e.g. MinGW). Some compilers have their own runtime libraries.

With Version 14.0 (Visual Studio 2015), most of the C/C++ runtime was moved into a new DLL, UCRTBASE.DLL, that is strictly C99 compliant[1]. Universal C Run Time (UCRT) from Windows 10 onwards become a component part of Windows[2], so every compiler (either non MS, like GCC or Clang/LLVM) can link against UCRT[3]. However, C/C++ programs using UCRTBASE.DLL are forced to link against another new DLL, the VCRuntime. At Version 14.0, this was VCRUNTIME140.DLL.[18] The name has the potential to change at future versions, but has not done so as far as of Version 17.0.

Source code for runtime libraries is included in Visual C++[19] for reference and debugging (e.g. in C:\Program Files\Microsoft Visual Studio 11.0\VC\crt\src).

Other runtime libraries

  • ATL*.DLL – Active Template Library
  • MFC*.DLL –
    Microsoft Foundation Classes
  • MSVBVM60.DLL –
    Visual Basic.NET programs require .NET Framework
    instead)
  • VCOMP*.DLL – Microsoft OpenMP runtime
  • VCRUNTIME*.DLL – Microsoft VCRuntime, for MSVC 14.0+
  • MSVCIRT.DLL – Microsoft C++ Library, contains the deprecated C++ classes from <iostream.h> (note the file extension) for MS C 9 and 10 (MSVC 2.x, 4.x) (Back then, the draft C++ Standard Library was integrated within MSVCRT.DLL. It was split up with the release of Visual C++ 5.0)

.NET Framework libraries

Programs written in

Visual Basic.NET, C++/CLI and other .NET languages require the .NET Framework. It has many libraries (one of them is mscorlib.dll – Multilanguage Standard Common Object Runtime Library, formerly Microsoft Common Object Runtime Library[20]) and so-called assemblies
(e.g. System.Windows.Forms.dll).

See also

References

  1. ISBN 978-1-59822-061-2
    .
  2. ^ @PetrBenes (July 25, 2019). "Did I miss something? Routines..." (Tweet) – via Twitter.
  3. ISBN 978-1-118-07976-8
    .
  4. ^ a b "Inside Native Windows Applications". Microsoft. Archived from the original on 2010-09-12. Retrieved 2011-12-14.
  5. ISBN 978-0-7356-3796-2
    .
  6. ISBN 978-3-540-49496-6
    .
  7. ^ "Inside Native Applications". Archived from the original on 2010-10-23. Retrieved 2017-08-26.
  8. ^ a b Visual Studio Developer Center: Identifying Functions in DLLs
  9. Wine implementation of GDI32.DLL: Wine API: gdi32.dll
  10. ISBN 978-0-13-086985-2
    .
  11. ^ "Common Dialog Box Library (Windows)". msdn.microsoft.com. Retrieved 2017-10-25.
  12. ^ Microsoft. "How RPC Works: Remote Procedure Call (RPC) | Microsoft Learn". Retrieved 11 September 2023.
  13. ^ "WD: What is a Scrap (.shs) file?". Microsoft Knowledge Base.
  14. ^ Raymond Chen. "Windows Confidential: Scrapping the Scraps". Retrieved 2011-12-14.
  15. ^ "VBS.Stages.A". symantec.com.
  16. ^ "How to open SHS files". Retrieved 2011-12-14.
  17. ^ "C Run-Time Libraries". Archived from the original on 2011-12-07. Retrieved 2011-12-14.
  18. ^ "C++ binary compatibility 2015-2022".
  19. ^ "Source Code for the C Run-Time Functions".
  20. ^ "What does the "ms" in "mscorlib" stand for - hint: It's not "Microsoft"".

External links

Wikibooks has a book on the topic of: Windows Programming/GDI and Drawing
Retrieved from "https://en.wikipedia.org/w/index.php?title=Microsoft_Windows_library_files&oldid=1220739507"