Hi Andi, On Tue, Nov 23, 2010 at 11:15 AM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote: > > Here's a draft manpage for recvmmsg(2), which is one > of the last undocumented syscalls currently. > Please review and comment. Thanks for this page. Can you tell me what license and copyright should be assigned to it? See http://man7.org/linux/man-pages/licenses.html Thanks, Michael > -Andi > > > .TH RECVMMSG 2 2010-11-23 "Linux" "Linux Programmer's Manual" > .SH NAME > recvmmsg \- receive multiple messages on a socket > .SH SYNOPSIS > .BI "#include <sys/socket.h>" > .br > .BI "int recvmmsg(int " fd ", struct mmsghdr *" mmsghdr \ > ", unsigned int " vlen "," > .br > .BI " unsigned int " flags ", struct timespec *" timeout ");" > .SH DESCRIPTION > The > .B recvmmsg > system call receives multiple messages in a socket. > It acts similar to > .B recvmsg(2), > but allows to batch multiple receive operations into a single syscall. > In addition it support an explicit timeout. > > .B fd > is the file descriptor of the socket to receive data from. > .B mmsghdr > is a pointer to an array with length > .B vlen > of > .I mmsghdr > structures. > .I struct mmsg > is defined in > .I sys/socket.h > as: > .in +4n > .nf > struct mmsghdr { > struct msghdr msg_hdr; /* Message header */ > unsigned int msg_len; /* Number of received bytes for header */ > }; > .fi > .in > .PP > .B msg_hdr > is a struct > .I msghdr > as described in > .I recvmsg(2). > .B msg_len > is the number of bytes returned for the message in the entry. > This field has the same value as the return value of a single > .I recvmsg(2) > on the header. > > .B flags > contains flags ored together. The flags are the same > as documented for > .I recvmsg(2). > The additional > .B MSG_WAITFORONE > turns one > .I MSG_DONTWAIT > after the first message has been received. > > .B timeout > points to a > .I struct timespec > (see > .I clock_gettime(2) > ) > defining a timeout for receiving, or > .I NULL > for no timeout. When the timeout expires > .I recvmmsg > returns. > .SH RETURN VALUE > .I recvmmsg > returns the number of messages received in > .I mmsghdr > or > -1 > when an error occurs. The > .I msg_len > members of > .I mmsghdr > are updated for each received message, > in addition to other fields in the msg_hdr for each message, > as described in > .I recvmsg(2). > .SH SEE ALSO > .B recvmsg(2), > .B sendmsg(2), > .B socket(7), > .B socket(2), > .B clock_gettime(2) > .SH VERSIONS > The > .I recvmmsg > syscall was added with kernel 2.6.32. > Support in glibc was added with 2.6.12. > On earlier glibcs the function can be called > manually using > .I syscall(2). > > > -- > ak@xxxxxxxxxxxxxxx -- Speaking for myself only. > -- > 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 > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface"; http://man7.org/tlpi/ -- 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
