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endurox:v7.5.x:api:ubf:breadcb.3
Name
Breadcb — Read the UBF buffer from Bwritecb(3) serialized format
Synopsis
#include <ubf.h>
int Breadcb (UBFH * p_ub, long (*p_readf)(char *buffer, long bufsz, void *dataptr1), void *dataptr1);
Link with -lubf -lnstd -lm -lpthread
DESCRIPTION
Breadcb() is a function which reads UBF/p_ub buffer from the callback function. specified in p_readf argument. The arguments to callback are buffer which is data buffer into which data must be read. The number of bytes required by particular request are specified in bufsz. This is precise number of bytes that are required to be read from the data source. Basically two read requests are performed by the function. The first reads the header and the scond extracts from the header buffer length and remaining bytes are read. The dataptr1 argument to callback are forwarded from main function arguments. This is usable for cases when some other control objects must be passed to callback. The callback must return number of bytes read from the source. For success case parameter bufsz must be return from the callback (i.e. read bytes matches), otherwise Breadcb() will fail. In case of failure inside the callback, return value -1.
RETURN VALUE
On success, Breadcb() return zero; on error, -1 is returned, with Berror set to indicate the error.
ERRORS
Note that Bstrerror() returns generic error message plus custom message with debug info from last function call.
BALIGNERR Corrupted buffer or pointing to not aligned memory area.
BNOTFLD Buffer not fielded, not correctly allocated or corrupted.
BEINVAL readf is NULL.
BEUNIX Failed to read from stream.