hi all,
i meet a problem when opening a socket, is that when the remote host not available or its port hanged ,my program still suspending untill i cancel the operation...
but when the host is ok ,my program work ok.
i handled in my code all these exceptions ,but my problem is when the host is not avaialable i want to exit with that error ???!!!!
here is the part of my code for socket programming :
N.B:
this code runs under UNIX sun solaris OS
thanks.
Hello,
I actually try to make client-server program.
I'm using SCO OpenServer Release 5.0.0 and when I try to compile my code (by TELNET) I've got this error :
I'm just using this simple code :
and I get the same error if I use :
If someone can help me,
Thanks (2 Replies)
If I do a netstat -a I can see all the sockets currently open, is there a way that I can tell which application is holding open these sockets ? (3 Replies)
Hi all,
I am trying to connect the open socket and its owner PID on my Solaris9 system. But it seems not very easy.
As netstat is not as powerful as it is on Linux platform, without the "-program" option, and "lsof -i <UDP|TCP>@<hostIP>" won't show the one i want although it lists some... (1 Reply)
Hello,
I want to test a firewall rule between 2 servers A & B.
I need a command that will open a socket on the server A such as:
themagiccommand MyPort
And on the client server B, i will run the command
telnet IP_serverA Myport
Can you help me ?
Thank you
Gunther (0 Replies)
Hi,
I was porting ipv4 application to ipv6; i was done with TCP transports. Now i am facing problem with SCTp transport at runtime.
To test SCTP transport I am using following server and client socket programs. Server program runs fine, but client program fails giving Invalid Arguments for... (0 Replies)
Hi all,
On the server side, one socket is used for listening, the others are used for communicating with the client.
My question is: if i want to set option for socket, which socket should be set on?
If either can be set, what's the different?
Again, what's the different if set option... (1 Reply)
Why does this socket function only read the first 1440 chars of the stream. Why not the whole stream ? I checked it with gdm and valgrind and everything seems correct...
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include... (3 Replies)
Dear Experts,
i am compiling my code in suse 4.1 which is compiling fine,
but at runtime it is showing me for socket programming error no 88
as i searched in errno.h it is telling me socket operation on non socket,
what is the meaning of this , how to deal with this error , please... (1 Reply)
I need clarification on whether it is okay to set socket options on a listening socket
simultaneously when it is being used in an accept() call?
Following is the scenario:-
-- Task 1 - is executing in a loop - polling a listen socket, lets call it 'fd', (whose file descriptor is global)... (2 Replies)
Discussion started by: jake24
2 Replies
LEARN ABOUT SUNOS
sendmmsg
SENDMMSG(2) Linux Programmer's Manual SENDMMSG(2)NAME
sendmmsg - send multiple messages on a socket
SYNOPSIS
#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <sys/socket.h>
int sendmmsg(int sockfd, struct mmsghdr *msgvec, unsigned int vlen,
int flags);
DESCRIPTION
The sendmmsg() system call is an extension of sendmsg(2) that allows the caller to transmit multiple messages on a socket using a single
system call. (This has performance benefits for some applications.)
The sockfd argument is the file descriptor of the socket on which data is to be transmitted.
The msgvec argument is a pointer to an array of mmsghdr structures. The size of this array is specified in vlen.
The mmsghdr structure is defined in <sys/socket.h> as:
struct mmsghdr {
struct msghdr msg_hdr; /* Message header */
unsigned int msg_len; /* Number of bytes transmitted */
};
The msg_hdr field is a msghdr structure, as described in sendmsg(2). The msg_len field is used to return the number of bytes sent from the
message in msg_hdr (i.e., the same as the return value from a single sendmsg(2) call).
The flags argument contains flags ORed together. The flags are the same as for sendmsg(2).
A blocking sendmmsg() call blocks until vlen messages have been sent. A nonblocking call sends as many messages as possible (up to the
limit specified by vlen) and returns immediately.
On return from sendmmsg(), the msg_len fields of successive elements of msgvec are updated to contain the number of bytes transmitted from
the corresponding msg_hdr. The return value of the call indicates the number of elements of msgvec that have been updated.
RETURN VALUE
On success, sendmmsg() returns the number of messages sent from msgvec; if this is less than vlen, the caller can retry with a further
sendmmsg() call to send the remaining messages.
On error, -1 is returned, and errno is set to indicate the error.
ERRORS
Errors are as for sendmsg(2). An error is returned only if no datagrams could be sent. See also BUGS.
VERSIONS
The sendmmsg() system call was added in Linux 3.0. Support in glibc was added in version 2.14.
CONFORMING TO
sendmmsg() is Linux-specific.
NOTES
The value specified in vlen is capped to UIO_MAXIOV(1024).
BUGS
If an error occurs after at least one message has been sent, the call succeeds, and returns the number of messages sent. The error code is
lost. The caller can retry the transmission, starting at the first failed message, but there is no guarantee that, if an error is
returned, it will be the same as the one that was lost on the previous call.
EXAMPLE
The example below uses sendmmsg() to send onetwo and three in two distinct UDP datagrams using one system call. The contents of the first
datagram originates from a pair of buffers.
#define _GNU_SOURCE
#include <netinet/ip.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
int
main(void)
{
int sockfd;
struct sockaddr_in addr;
struct mmsghdr msg[2];
struct iovec msg1[2], msg2;
int retval;
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if (sockfd == -1) {
perror("socket()");
exit(EXIT_FAILURE);
}
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
addr.sin_port = htons(1234);
if (connect(sockfd, (struct sockaddr *) &addr, sizeof(addr)) == -1) {
perror("connect()");
exit(EXIT_FAILURE);
}
memset(msg1, 0, sizeof(msg1));
msg1[0].iov_base = "one";
msg1[0].iov_len = 3;
msg1[1].iov_base = "two";
msg1[1].iov_len = 3;
memset(&msg2, 0, sizeof(msg2));
msg2.iov_base = "three";
msg2.iov_len = 5;
memset(msg, 0, sizeof(msg));
msg[0].msg_hdr.msg_iov = msg1;
msg[0].msg_hdr.msg_iovlen = 2;
msg[1].msg_hdr.msg_iov = &msg2;
msg[1].msg_hdr.msg_iovlen = 1;
retval = sendmmsg(sockfd, msg, 2, 0);
if (retval == -1)
perror("sendmmsg()");
else
printf("%d messages sent
", retval);
exit(0);
}
SEE ALSO recvmmsg(2), sendmsg(2), socket(2), socket(7)COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the
latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
Linux 2018-02-02 SENDMMSG(2)