The lld_seek() function
This function sets the position for the next read or write operation to or from a large object that is open for reading or writing.
Syntax
API
mi_integer lld_seek(conn, io, offset, whence, new_offset, error)
MI_CONNECTION* conn
LLD_IO* io;
mi_int8* offset;
mi_integer whence;
mi_int8* new_offset;
mi_integer* error; ESQL/C
int lld_seek(io,offset, whence, new_offset, error)
LLD_IO* io;
EXEC SQL BEGIN DECLARE SECTION;
PARAMETER int8* offset;
EXEC SQL END DECLARE SECTION;
EXEC SQL BEGIN DECLARE SECTION;
PARAMETER int8* new_offset;
EXEC SQL END DECLARE SECTION;
int whence;
int* error;- conn
- The connection descriptor established by a previous call to the mi_open() or mi_server_connect() functions. This parameter is for the API interface only. In the ESQL/C and SQL versions of this function, you must already be connected to a server.
- io
- A pointer to an LLD_IO structure created with a previous call to the lld_open() function.
- offset
- A pointer to the offset. It describes where to seek in the object.
Its value depends on the value of the whence parameter.
- If whence is LLD_SEEK_SET, the offset is measured relative to the beginning of the object.
- If whence is LLD_SEEK_CUR, the offset is relative to the current position in the object.
- If whence is LLD_SEEK_END, the offset is relative to the end of the file.
- whence
- Determines how the offset is interpreted.
- new_offset
- A pointer to an int8 that you allocate. The function returns the new offset in this int8.
- error
- An output parameter in which the function returns an error code.
Usage
Before calling this function, you must open the large object with a call to lld_open().
Although this function takes an 8-byte offset, this offset is converted to the appropriate size for the underlying large object storage system. For example, if the large object is stored in a 32-bit file system, the 8-byte offset is converted to a 4-byte offset, and any attempt to seek past 4 GB generates an error.
Return codes
For an API function, returns MI_OK if
the function succeeds and MI_ERROR if it fails.
For
an ESQL/C function, returns 0 if the function succeeds
and -1 if the function fails.