LZInit function

Allocates memory for the internal data structures required to decompress files, and then creates and initializes them.


  INT hfSource



A handle to the file.

Return Value

If the function succeeds, the return value is a new LZ file handle.

If the function fails, the return value is an LZERROR_* code. These codes have values less than zero. Note that LZInit 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 LZInit can return upon failure.

Return code Description
The handle identifying the source file is not valid. The file cannot be read.
The maximum number of open compressed files has been exceeded or local memory cannot be allocated.
The LZ file handle cannot be locked down.
The file is compressed with an unrecognized compression algorithm.

There is no extended error information for this function; do not call GetLastError.


A maximum of 16 compressed files can be open at any given time. Similarly, a maximum of 16 uncompressed files can be open at any given time. An application should be careful to close the handle returned by LZInit when it is done using the file; otherwise, the application can inadvertently hit the 16-file limit.

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

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.


Minimum supported client Windows XP [desktop apps only]
Minimum supported server 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