LZOpenFileA function

Creates, opens, reopens, or deletes the specified file.

Syntax

INT LZOpenFileA(
  LPSTR      lpFileName,
  LPOFSTRUCT lpReOpenBuf,
  WORD       wStyle
);

Parameters

lpFileName

The name of the file.

lpReOpenBuf

A pointer to the OFSTRUCT structure that is to receive information about the file when the file is first opened. The structure can be used in subsequent calls to the LZOpenFile function to see the open file.

The szPathName member of this structure contains characters from the original equipment manufacturer (OEM) character set.

wStyle

The action to be taken. This parameter can be one or more of the following values.

Value Meaning
OF_CANCEL
0x0800
Ignored. Provided only for compatibility with 16-bit Windows. Use the OF_PROMPT style to display a dialog box containing a Cancel button.
OF_CREATE
0x1000
Directs LZOpenFile to create a new file. If the file already exists, it is truncated to zero length.
OF_DELETE
0x0200
Deletes the file.
OF_EXIST
0x4000
Opens the file and then closes it to test for a file's existence.
OF_PARSE
0x0100
Fills the OFSTRUCT structure but carries out no other action.
OF_PROMPT
0x2000
Displays a dialog box if the requested file does not exist. The dialog box informs the user that the system cannot find the file, and it contains Retry and Cancel buttons. Clicking the Cancel button directs LZOpenFile to return a file not found error message.
OF_READ
0x0000
Opens the file for reading only.
OF_READWRITE
0x0002
Opens the file for reading and writing.
OF_REOPEN
0x8000
Opens the file using information in the reopen buffer.
OF_SHARE_DENY_NONE
0x0040
Opens the file without denying other processes read or write access to the file. LZOpenFile fails if the file has been opened in compatibility mode by any other process.
OF_SHARE_DENY_READ
0x0030
Opens the file and denies other processes read access to the file. LZOpenFile fails if the file has been opened in compatibility mode or has been opened for read access by any other process.
OF_SHARE_DENY_WRITE
0x0020
Opens the file and denies other processes write access to the file. LZOpenFile fails if the file has been opened in compatibility mode or has been opened for write access by any other process.
OF_SHARE_EXCLUSIVE
0x0010
Opens the file in exclusive mode, denying other processes both read and write access to the file. LZOpenFile fails if the file has been opened in any other mode for read or write access, even by the current process.
OF_WRITE
0x0001
Opens the file for writing only.

Return Value

If the function succeeds and the value specified by the wStyle parameter is not OF_READ, the return value is a handle identifying the file. If the file is compressed and opened with wStyle set to OF_READ, the return value is a special file handle.

If the function fails, the return value is an LZERROR_* code. These codes have values less than zero. There is no extended error information for this function; do not call GetLastError.

Note  LZOpenFile calls neither SetLastError nor SetLastErrorEx; thus, its failure does not affect a thread's last-error code.
 
The following is the list of the error codes that LZOpenFile can return upon failure.
Return code/value Description
LZERROR_BADINHANDLE
-1
The handle identifying the source file is not valid. The file cannot be read.
LZERROR_GLOBALLOC
-5
The maximum number of open compressed files has been exceeded or local memory cannot be allocated.

Remarks

If the wStyle parameter is the OF_READ flag (or OF_READ and any of the OF_SHARE_* flags) and the file is compressed, LZOpenFile calls the LZInit function, which performs the required initialization for the decompression operations.

The handle this function returns is compatible only with the functions in Lz32.dll; it should not be used for other file operations.

If LZOpenFile is unable to open the file specified by lpFileName, on some versions of Windows it attempts to open a file with almost the same file name, except the last character is replaced with an underscore (""). Thus, if an attempt to open "MyProgram.exe" fails, LZOpenFile tries to open "MyProgram.ex". Installation packages often substitute the underscore for the last letter of a file name extension to indicate that the file is compressed. For example, "MyProgram.exe" compressed might be named "MyProgram.ex_". To determine the name of the file opened (if any), examine the szPathName member of the OFSTRUCT structure in the lpReOpenBuf parameter.

In Windows 8 and Windows Server 2012, this function is supported by the following technologies.

Technology Supported
Server Message Block (SMB) 3.0 protocol Yes
SMB 3.0 Transparent Failover (TFO) Yes
SMB 3.0 with Scale-out File Shares (SO) Yes
Cluster Shared Volume File System (CsvFS) Yes
Resilient File System (ReFS) Yes
 

CsvFs will do redirected IO for compressed files.

Requirements

   
Windows version Windows XP [desktop apps only] Windows Server 2003 [desktop apps only]
Target Platform Windows
Header lzexpand.h (include Windows.h)
Library Lz32.lib
DLL Lz32.dll

See Also

File Compression and Decompression

File Management Functions

LZClose

LZInit

LZRead

OFSTRUCT