Linux Standard Base Core Specification 3.0Preview1 | ||
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The deflateInit_() function shall initialize the compression system. On entry, stream 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, deflateInit_() shall fail, and return
Z_VERSION_ERROR
.
The level supplied shall be a value between
0
and 9
, or the value
Z_DEFAULT_COMPRESSION
. A level
of 1
requests the highest speed, while a
level
of 9
requests the highest compression.
A level of 0
indicates that no
compression should be used, and the output shall be the same as the input.
The deflateInit_() function is not in the source standard; it is only in the binary standard. Source applications should use the deflateInit() macro.
The deflateInit_() function is equivalent to
deflateInit2_(stream, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY, version, stream_size); |
On success, the deflateInit_() function shall return
Z_OK
.
Otherwise, deflateInit_() shall return
a value as described below to indicate the error.
On error, deflateInit_() 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
stream
may be set to an error message.
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