CMSG_LEN (3) Linux Manual Page
CMSG_ALIGN, CMSG_SPACE, CMSG_NXTHDR, CMSG_FIRSTHDR – access ancillary data Synopsis#include <sys/socket.h> struct cmsghdr *CMSG_FIRSTHDR(struct msghdr *msgh); struct cmsghdr *CMSG_NXTHDR(struct msghdr *msgh, struct cmsghdr *cmsg); size_t CMSG_ALIGN(size_t length); size_t CMSG_SPACE(size_t length); size_t CMSG_LEN(size_t length); unsigned char *CMSG_DATA(struct cmsghdr *cmsg);DescriptionThese macros are used to create and access control messages (also called ancillary data) that are not a part…
