Miscellaneous Low-Level Client Support

This topic contains information about low-level APIs that are used by the Windows client infrastructure.

Functions

Topic Contents
[_lclose](/windows/desktop/api/winbase/nf-winbase-_lclose) The _lclose function closes the specified file so that it is no longer available for reading or writing. This function is provided for compatibility with 16-bit versions of Windows. Win32-based applications should use the CloseHandle function.
[_lopen](/windows/desktop/api/winbase/nf-winbase-_lopen) The _lopen function opens an existing file and sets the file pointer to the beginning of the file. This function is provided for compatibility with 16-bit versions of Windows. Win32-based applications should use the CreateFile function.
[_lread](/windows/desktop/api/winbase/nf-winbase-_lread) The _lread function reads data from the specified file. This function is provided for compatibility with 16-bit versions of Windows. Win32-based applications should use the ReadFile function.
[AreDvdCodecsEnabled](/windows/desktop/api/comppkgsup/nf-comppkgsup-aredvdcodecsenabled) Returns a value indicating whether DVD codecs are enabled on the current device.
[DisableProcessWindowsGhosting](/windows/desktop/api/Winuser/nf-winuser-disableprocesswindowsghosting) Disables the window ghosting feature for the calling GUI process. Window ghosting is a Windows Manager feature that lets the user minimize, move, or close the main window of an application that is not responding.
[GetMediaComponentPackageInfo](/windows/desktop/api/comppkgsup/nf-comppkgsup-getmediacomponentpackageinfo) Returns a list of properties for all media codecs installed on the system that meet the specified requirements.
[GetMediaExtensionCommunicationFactory](/windows/desktop/api/comppkgsup/nf-comppkgsup-getmediaextensioncommunicationfactory) Creates a communication factory for registering a media extension.
[InstantiateComponentFromPackage](/windows/desktop/api/comppkgsup/nf-comppkgsup-instantiatecomponentfrompackage) Creates an instance of a class in an application package.
[IsMediaBehaviorEnabled](/windows/desktop/api/comppkgsup/nf-comppkgsup-ismediabehaviorenabled) Gets a value indicating whether the media behavior associated with the specified GUID is enabled.
[NtClose](/windows/desktop/api/Winternl/nf-winternl-ntclose) Deprecated. This function is used to close the specified handle. [NtClose](/windows/desktop/api/Winternl/nf-winternl-ntclose) is superseded by [CloseHandle](http://msdn.microsoft.com/en-us/library/ms724211(VS.85).aspx).
[NtDeviceIoControlFile](/windows/desktop/api/Winternl/nf-winternl-ntdeviceiocontrolfile) Deprecated. Builds descriptors for the supplied buffer(s) and passes the untyped data to the device driver associated with the file handle. [NtDeviceIoControlFile](/windows/desktop/api/Winternl/nf-winternl-ntdeviceiocontrolfile) is superseded by [DeviceIoControl](http://msdn.microsoft.com/en-us/library/aa363216(VS.85).aspx).
[NtWaitForSingleObject](/windows/desktop/api/Winternl/nf-winternl-ntwaitforsingleobject) Deprecated. Waits until the specified object attains a state of signaled. [NtWaitForSingleObject](/windows/desktop/api/Winternl/nf-winternl-ntwaitforsingleobject) is superseded by [WaitForSingleObject](http://msdn.microsoft.com/en-us/library/ms687032.aspx).
[RtlAnsiStringToUnicodeString](/windows/desktop/api/Winternl/nf-winternl-rtlansistringtounicodestring) Converts the specified ANSI source string into a Unicode string.
[RtlCharToInteger](/windows/desktop/api/Winternl/nf-winternl-rtlchartointeger) Converts a character string to an integer.
[RtlFormatCurrentUserKeyPath](winprog.rtlformatcurrentuserkeypath) Initializes the supplied buffer with a string representation of the SID for the current user.
[RtlFreeAnsiString](/windows/desktop/api/Winternl/nf-winternl-rtlfreeansistring) Frees the string buffer allocated by [RtlUnicodeStringToAnsiString](/windows/desktop/api/Winternl/nf-winternl-rtlunicodestringtoansistring).
[RtlFreeOemString](/windows/desktop/api/Winternl/nf-winternl-rtlfreeoemstring) Frees the string buffer allocated by [RtlUnicodeStringToOemString](/windows/desktop/api/Winternl/nf-winternl-rtlunicodestringtooemstring).
[RtlFreeUnicodeString](/windows/desktop/api/Winternl/nf-winternl-rtlfreeunicodestring) Frees the string buffer allocated by [RtlAnsiStringToUnicodeString](/windows/desktop/api/Winternl/nf-winternl-rtlansistringtounicodestring) or by [RtlUpcaseUnicodeString](http://msdn.microsoft.com/en-us/library/ms803011.aspx).
[RtlInitString](/windows/desktop/api/Winternl/nf-winternl-rtlinitstring) Initializes a counted string.
[RtlInitUnicodeString](/windows/desktop/api/Winternl/nf-winternl-rtlinitunicodestring) Initializes a counted Unicode string.
[RtlUnicodeStringToAnsiString](/windows/desktop/api/Winternl/nf-winternl-rtlunicodestringtoansistring) Converts the specified Unicode source string into an ANSI string.
[RtlUnicodeStringToOemString](/windows/desktop/api/Winternl/nf-winternl-rtlunicodestringtooemstring) This functions converts the specified Unicode source string into an OEM string. The translation is done with respect to the OEM code page (OCP).
[RtlUnicodeToMultiByteSize](/windows/desktop/api/Winternl/nf-winternl-rtlunicodetomultibytesize) Determines how many bytes are needed to represent a Unicode string as an ANSI string.
[RtlUnicodeToUTF8N](rtlunicodetoutf8n.md) The [RtlUnicodeToUTF8N](rtlunicodetoutf8n.md) function translates the specified Unicode string into a new character string, using the 8-bit Unicode Transformation Format (UTF-8) code page.
[RtlUTF8ToUnicodeN](rtlutf8tounicoden.md) The [RtlUTF8ToUnicodeN](rtlutf8tounicoden.md) function translates the specified source string into a Unicode string, using the UTF-8 code page.
[SendIMEMessageEx](/windows/desktop/api/Ime/nf-ime-sendimemessageexa) Specifies an action or processing for the Input Method Editor (IME) through a specified subfunction.
[!Note]
This function is obsolete and should not be used.


[WINNLSEnableIME](/windows/desktop/api/Winnls32/nf-winnls32-winnlsenableime) Temporarily enables or disables an IME and, at the same time, turns on or off the display of all windows owned by the IME.
[!Note]
This function is obsolete and should not be used.


 

Structures

Topic Contents
IMESTRUCT Used by SendIMEMessageEx to specify the subfunction to be executed in the IME message and its parameters. This structure is also used to receive return values from those subfunctions.
STRING This structure is used with the RtlUnicodeStringToOemString function.

 

Compiler Routines

Topic Contents
__C_specific_handler Routine __C_specific_handler is a helper routine for the C compiler.
_alldiv Routine _alldiv Routine is a helper routine for the C compiler.
_chkstk Routine _chkstk Routine is a helper routine for the C compiler.