The CPackage::ExtractFile function extracts the specified file from the package, storing it on the local system.

BOOL ExtractFile(
	DWORD dwFilePlatform,		// file platform
	DWORD dwFileChecksum,		// file checksum
	LPCTSTR lpszFileName,		// file name in package
	LPCTSTR lpszLocalFile		// local file name
);

Parameters

dwFilePlatform

[in] Specifies the target platform for the file.

 

This may be one of the following values:

Value	Description
PACKAGE_FILE_PLATFORM_DEFAULT	The file may be applied on all Windows platforms. This is the same as specifying a value of PACKAGE_FILE_PLATFORM_WINDOWS.
PACKAGE_FILE_PLATFORM_WIN95	The file may be applied to a system running Windows 95.
PACKAGE_FILE_PLATFORM_WIN98	The file may be applied to a system running Windows 98 or Windows 98 SE.
PACKAGE_FILE_PLATFORM_WINME	The file may be applied to a system running Windows ME.
PACKAGE_FILE_PLATFORM_WINNT40	The file may be applied to a system running Windows NT 4.0.
PACKAGE_FILE_PLATFORM_WIN2000	The file may be applied to a system running Windows 2000.
PACKAGE_FILE_PLATFORM_WINXP	The file may be applied to a system running Windows XP.
PACKAGE_FILE_PLATFORM_WIN2003	The files may be applied to a system running Windows Server 2003.

In addition to the above platform-specific values, there are predefined values which specify platform groups:

 

Value	Description
PACKAGE_FILE_PLATFORM_WIN32	The file may be applied to any 32-bit version of the Windows operating system.
PACKAGE_FILE_PLATFORM_WIN9X	The file may be applied to any system running Windows 95, Windows 98 or Windows ME. The file will not be applied on a system running Windows NT, Windows 2000 or Windows XP.
PACKAGE_FILE_PLATFORM_WINNT	The file may be applied to any system running Windows NT, Windows 2000 or Windows XP. The file will not be applied on a system running Windows 95, Windows 98 or Windows ME.
PACKAGE_FILE_PLATFORM_WINDOWS	The files may be applied to any system running any version of Microsoft Windows.

dwFileChecksum

[in] Specifies the 32-bit checksum for the file. If the package contains multiple file versions, this value is used to uniquely identify the file. This parameter is ignored if the PACKAGE_OPTION_MULTIPLE_VERSIONS package option has not been enabled or if the parameter value is zero.

 

lpszFileName

[in] A pointer to a null-terminated string which specifies the name of the file to extract from the package.

 

lpszLocalFile

[in] A pointer to a null-terminated string which specifies the name of the local file that will contain the extracted package file.

Return Values

If the CPackage::ExtractFile function succeeds, it will return a non-zero value.

If the function fails, it will return a value of zero. To get extended error information, call GetLastError.

Remarks

This function will return an error if the specified package file specifies a file that is to be removed from the target platform. No file data is actually stored in the package for files that are to be removed.

The extracted file is not actually applied on the local system. If the local file already exists, it will be overwritten. If the package file is a patch file, it must be applied using the CPatchFile::Apply function.

Requirements

Windows NT/2000/XP: Requires Windows NT 4.0 SP3 or later.
Windows 95/98: Requires Windows 95 or later.
Header: Include apatch.h.
Library: Use apatch32.lib.
Unicode: Implemented as Unicode and ANSI versions on Windows NT/2000/XP.

See Also

CPatchFile::Apply, CPackage::StoreFile