#include opcapi.h
int opcif_read(
int interface_id, /* in */
opcdata data /* in/out */
);
Parameters
interface_id
data
Description
The function opcif_read()
reads a message from the
queue of the specified interface instance. If the interface
instance has been opened with OPCIF_READ_WAIT
, the
calling process is blocked until the information is available. The
API returns an error if the application receives an interrupt
signal. The data parameter specified in the call must be created
with opcdata_create()
. Memory for the actual message
data is allocated, and if memory was assigned to data before the
call to opcif_read()
, it is deallocated.
Return Values
OPC_ERR_OK
OPC_ERR_CANT_INIT
OPC_ERR_INVALID_INTERFACE_ID
OPC_ERR_INVALID_OUTPARAM
data
is NULL or is of the wrong type.OPC_ERR_WRONG_MSITYPE
interface_id
is of the wrong
type.OPC_ERR_EINTR
OPC_ERR_MSI_BUF_FULL
max_entries
while opening.OPC_ERR_NO_DATA
OPC_ERR_CANT_READ_MSG
OPC_ERR_NO_MEMORY
Versions
HPOM for Windows 8.00 and higher