WNetAddConnection

This function allows the caller to redirect (connect) a local device to a network resource. If successful, the connection will be made persistent.

DWORD WNetAddConnection(
    LPTSTR lpRemoteName,
    LPTSTR lpPassword,
    LPTSTR lpLocalName
    );

lpRemoteName: Specifies the network resource to connect to. This is limited to MAX_PATH.
lpPassword: Specifies the password to be used in making the connection.
The NULL value or string may be passed in to indicate that the caller wants the network to use the best password(s) it has available (such as no password, a default password, or an internally cached password).
lpLocalName: This should contain the name of a local device to be redirected, such as "F:" or "LPT1". The string is treated in a case insensitive manner, and may be the empty string (or NULL) to indicate the connection to the network resource is to be made without a device redirection (i.e., deviceless connection).

ERROR_BAD_DEV_TYPE	The device type and the resource type do not match.
WN_BAD_NETNAME	lpRemoteName is not acceptable to any NP
WN_BAD_LOCALNAME	lpLocalName is invalid.
WN_BAD_PASSWORD	invalid password, or the the connection requires additional authentication not provided by the caller (e.g., a username)
WN_ALREADY_CONNECTED	lpLocalName is already connected to a network drive or is to a local drive that is already in use locally (e.g. is used for a hard drive or RAM drive).
WN_ACCESS_DENIED	access denied (user may need to logon)
WN_NO_NETWORK	network is not present
WN_CANNOT_OPEN_PROFILE	Unable to open the user profile to process persistent connections.
WN_BAD_PROFILE	The user profile is in an incorrect format.
WN_FUNCTION_BUSY	The MPR or NP is busy (possibly initializing). The caller should retry.
WN_NO_NET_OR_BAD_PATH	the operation could not be handled either because a network component is not started or the specified name could not be handled.
WN_EXTENDED_ERROR	a network specific error occurred. WNetGetLastError should be called to obtain a description of the error.