Magtek MAGTEK User Manual download pdf (Page 63)

Section 5. Application Programmable Interface

McpOpen

This function is used to open the communication channel and establish communications with an

MCP device. Use McpClose to close the channel.

DWORD McpOpen( LPSTR lpDeviceName, PHANDLE hpDevice );

Parameters

lpDeviceName

Pointer to a null terminated string which specifies the logical device name of the MCP device to

which communications is to be established. This name could be a hard coded device name, a

name obtained from the registry, or other configuration data, or more likely, a name returned

from the McpEnum function.

hpDevice

Pointer to storage area to receive the open handle to the specified device (communications

resource). This handle is used on subsequent calls to functions requiring communications with

the MCP device. If the function fails, the value of hpDevice is not modified.

Return Value

The returned value indicates the outcome of the open function.

Value Meaning

MCP_ST_OK Success. The channel has been established.

MCP_ST_NOT_FOUND Unknown device or device not found

MCP_ST_ACCESS_DENI

Device is already open

MCP_ST_BAD_ACCESS lpDeviceName or hpDevice parameter is an invalid pointer

MCP_ST_FAILED Other error

Remarks

The host application uses McpOpen to open a handle to a communications resource.

If the specified resource is currently being used, this function fails. Any thread of the process can

use the handle returned by McpOpen to identify the resource in any of the functions that access

the resource.

Some devices automatically synchronize to communication parameters used by the host. For

example, some serial devices automatically synchronize to the baud rate the host is using. This

synchronization occurs during the call to McpOpen. Once a device is synchronized, it will not

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Magtek MAGTEK User Manual Page 63