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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) |