bindrv_newreader
bindrv_newreader |
Purpose
Synopsis
s_bindrvctx bindrv_newreader(size_t (*doread)(void *,size_t,size_t,void*), void *rctx);
Arguments
|
doread
|
Callback function to retrieve data from the input stream
|
|
rctx
|
File descriptor to be passed as the last argument of
doread
|
Return value
The new context or
NULL in case of error.
Example
In the following example the file
"bindata is opened using the C function
fopen and a reader is created based on the resulting file descriptor:
f=fopen("bindata", "r");
bdrv=bindrv_newreader((size_t (*)(void *,size_t,size_t,void*))fread, f);
Further information
1. Each context created using this function must be released by a call to
bindrv_delete.
2. The
doread routine is used by the reader whenever it requires further data to process. The function receives as input a buffer (where read data has to be copied), its size and, as the last argument, the pointer
rctx. The third argument of
doread is always 1. The return value must be
1 if successful (
i.e. the requested amount of data has been read), any other value is interpreted as an error condition.
3. The required
doread function has the same signature as the C function
fread such that a BinDrv reader can use as input a file opened with the C function
fopen.
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