Name

inflateInit2_ — Initializes the decompression system.

Library

Libz.lib

Synopsis

#include <zlib.h>
int inflateInit2_ (z_streamp strm, int windowBits, char * version,int stream_size);

Return Value

On success, the inflateInit2_() function shall return Z_OK. Otherwise, inflateInit2_() shall return a value as described below to indicate the error.

Detailed Description

The inflateInit2_() function shall initialize the decompression system. On entry, strm shall refer to a user supplied z_stream object (a z_stream_s structure). The following fields shall be set on entry:

`zalloc`		a pointer to an alloc_func function, used to allocate state information. If this is `NULL`, a default allocation function will be used.
`zfree`		a pointer to a free_func function, used to free memory allocated by the `zalloc` function. If this is `NULL` a default free function will be used.
`opaque`		If `alloc_func` is not `NULL`, `opaque` is a user supplied pointer to data that will be passed to the `alloc_func` and `free_func` functions.

If the version requested is not compatible with the version implemented, or if the size of the z_stream_s structure provided in stream_size does not match the size in the library implementation, inflateInit2_() shall fail, and return Z_VERSION_ERROR.

The windowBits parameter shall be a base 2 logarithm of the maximum window size to use, and shall be a value between 8 and 15. If the input data was compressed with a larger window size, subsequent attempts to decompress this data will fail with Z_DATA_ERROR, rather than try to allocate a larger window.

The inflateInit2_() function is not in the source standard; it is only in the binary standard. Source applications should use the inflateInit2() macro.

Examples

To initialize the decompression system with windowBits=15:

#include <stdio.h>
#include <zlib.h>   

void InflateInit2_( )
{ 
    z_stream d_stream; // decompression stream
    const char * version;
    d_stream.zalloc = (alloc_func)0;
    d_stream.zfree = (free_func)0;
    d_stream.opaque = (voidpf)0;
    version = zlibVersion();
    int ret =  inflateInit2_(&d_stream,15,version, sizeof(d_stream));
    inflateEnd(&d_stream);         
}

Errors

On error, inflateInit2_() shall return one of the following error indicators:

`Z_STREAM_ERROR`	Invalid parameter.
`Z_MEM_ERROR`	Insufficient memory available.
`Z_VERSION_ERROR`	The version requested is not compatible with the library version, or the z_stream size differs from that used by the library.

In addition, the msg field of the strm may be set to an error message.

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