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WSACMSGHDR structure (ws2def.h)

  • Article

The CMSGHDR structure defines the header for a control data object that is associated with a datagram.

Syntax

typedef struct _WSACMSGHDR {
  SIZE_T cmsg_len;
  INT    cmsg_level;
  INT    cmsg_type;
} WSACMSGHDR, *PWSACMSGHDR, *LPWSACMSGHDR;

Members

cmsg_len

The number of bytes from the beginning of the CMSGHDR structure to the end of the control data.

Note  The value of the cmsg_len member does not account for any padding that may follow the control data.
 

cmsg_level

The protocol that originated the control information.

cmsg_type

The protocol-specific type of control information.

Remarks

The control information data that is associated with a datagram is made up of one or more control data objects. Each object begins with a CMSGHDR structure.

Requirements

Requirement Value
Minimum supported client Available in Windows Vista and later versions of the Windows operating systems.
Header ws2def.h (include Wsk.h)

See also

WSK_DATAGRAM_INDICATION

WskReceiveFrom

WskSendTo