https://bugzilla.kernel.org/show_bug.cgi?id=15952 URL: http://bugs.gentoo.org/show_bug.cgi?id=318801 Summary: man page cmsg(3) inconsistency Product: Documentation Version: unspecified Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: man-pages AssignedTo: documentation_man-pages@xxxxxxxxxxxxxxxxxxxx ReportedBy: chris2k01@xxxxxxxxxxx Regression: No In man page cmsg(3), I see the following prose: "Finally, the msg_controllen field of the msghdr should be set to the sum of the CMSG_SPACE() of the length of all control messages in the buffer. For more information on the msghdr, see recvmsg(2)." Then, in the sample code at the bottom, I see this code: msg.msg_control = buf; msg.msg_controllen = sizeof buf; cmsg = CMSG_FIRSTHDR(&msg); cmsg->cmsg_level = SOL_SOCKET; cmsg->cmsg_type = SCM_RIGHTS; cmsg->cmsg_len = CMSG_LEN(sizeof(int) * NUM_FD); /* Initialize the payload: */ fdptr = (int *) CMSG_DATA(cmsg); memcpy(fdptr, myfds, NUM_FD * sizeof(int)); /* Sum of the length of all control messages in the buffer: */ msg.msg_controllen = cmsg->cmsg_len; This is inconsistent: the prose states that msg_controllen should be initialized with the sum of CMSG_SPACE across all messages, whereas the example code shows msg_controllen being initialized with cmsg->cmsg_len, which is itself initialized with CMSG_LEN, not CMSG_SPACE. I don't know what the right answer is, but for control messages whose length is not a multiple of the alignment requirement, this could make a difference. -- Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are watching the assignee of the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
