NAME

       odbx_lo_read - Reads content from a large object

SYNOPSIS

       #include <opendbx/api.h>

       ssize_t odbx_lo_read (odbx_lo_t* lo, void* buffer, size_t buflen);

DESCRIPTION

       To  get  the  content  of  a large object, odbx_lo_read() fetches the data in one or more pieces from the
       server and stores it into the user supplied buffer. After opening the large object using  odbx_lo_open(),
       the first call to odbx_lo_read() will return the bytes from the beginning. The second and all other calls
       will  store  subsequent  parts  of  the large object content into the buffer until the end of the data is
       reached. To reread the content a second time, you have to close the large object  handle  and  reopen  it
       again as some databases provide no way to reposition the internal file position indicator for the stream.

       The  lo parameter has to be the large object handle created and returned by odbx_lo_open() via its second
       parameter. It becomes invalid after it was supplied to odbx_lo_close() and this function will  return  an
       error  in  this  case.  The large object content fetched from the server is stored into the user supplied
       buffer up to buflen bytes.

RETURN VALUE

       odbx_lo_read() returns the number of bytes placed into buffer, which may be up to buflen  bytes.  If  the
       end of the content is reached and no more data is available, the return value will be 0. On error, a code
       whose  value  is  less than zero is returned if one of the operations couldn't be completed successfully.
       Possible error codes are listed in the error section and they can be feed to  odbx_error()  and  odbx_er‐
       ror_type() to get further details.

ERRORS

       -ODBX_ERR_BACKEND
              The native database library couldn't read from the large object

       -ODBX_ERR_HANDLE
              lo is NULL or the supplied large object handle is invalid

SEE ALSO

       odbx_lo_open(), odbx_lo_close()

                                                 8 January 2025                                  odbx_lo_read(3)