You can also use "sendfile()". That's a lot more efficient because it cuts the number of memory copies by half.
When you read data from a file into the address space of a process, usually the data is copied into a kernel buffer as it comes in off disk, and it get copied again from that kernel buffer into the process buffer. To send that data out a socket, the data is first copied into a kernel buffer, and the data in that buffer is copied out to the socket.
The sendfile() library call will bypass the copying of data into and out of the address space of the process.
For example (I left off all error checking for clarity):
Hi,
If some one was to suggest, "increase your kernal tunables related to UDP, in particular the UDP send/recieve buffer size".... then what would they mean? :confused:
How can I find out what this current value is?
Thousand many thanks.
Neil (3 Replies)
Hi All,
I encountered a stange problem while doing a perl script to use socket. i need to transfer a file from client to sever. but error came as argument missing in send function.........Plz tell me the wt r the arguments in send and recv functions....... (0 Replies)
Hi,
Am very new to socket programming.
When we use UDP sockets to communicate between two processess,
will both the client/server socket be able to send/recv ?
meaning can sendto()/ recvfrom() be used on both server and client?
It could be useful even if anybody provide some link on socket... (1 Reply)
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)
I have set the receive buffer size of socket to max.
setsockopt(sd,SOL_SOCKET, SO_RCVBUF,&max,optval);
Am reading data from the socket in a loop(say max 100 bytes per recv)
while(1)
{
int rlen=recv(sd,(void *)buf, 100 , 0);
//err handle and processing
}
Assume my process is slow... (2 Replies)
char name;
printf ("Welcome to the server \n");
printf ("Enter user name: \n");
scanf ("%c", &name);
how can client send name to server:what should be the code?
int send ( int sid , const char ∗buffer Ptr , int len , int f l a g )
how can client receive ack from... (1 Reply)
Hello everybody,
Years ago i left in stand-by a project of mine where the main program was supposed to send thousands ARP frames over the socket as fast as it could; but because of a programming issue i couldn't continue it.
2 days ago I decided to solve that issue.
The thing is, when the... (4 Replies)
Discussion started by: Zykl0n-B
4 Replies
LEARN ABOUT NETBSD
cltp
CLTP(4) BSD Kernel Interfaces Manual CLTP(4)NAME
cltp -- ISO Connectionless Transport Protocol
SYNOPSIS
#include <sys/socket.h>
#include <netiso/iso.h>
int
socket(AF_ISO, SOCK_DGRAM, 0);
DESCRIPTION
CLTP is a simple, unreliable datagram protocol which is accessed via the SOCK_DGRAM abstraction for the ISO protocol family. CLTP sockets
are connectionless, and are normally used with the sendto(2) and recvfrom(2) calls, though the connect(2) call may also be used to fix the
destination for future packets (in which case the recv(2) or read(2) and send(2) or write(2) system calls may be used).
CLTP address formats are identical to those used by TP. In particular CLTP provides a service selector in addition to the normal ISO NSAP.
Note that the CLTP selector space is separate from the TP selector space (i.e. a CLTP selector may not be ``connected'' to a TP selector).
Options at the CLNP network level may be used with CLTP; see clnp(4).
DIAGNOSTICS
A socket operation may fail with one of the following errors returned:
[EISCONN] when trying to establish a connection on a socket which already has one, or when trying to send a datagram with the destina-
tion address specified and the socket is already connected;
[ENOTCONN] when trying to send a datagram, but no destination address is specified, and the socket hasn't been connected;
[ENOBUFS] when the system runs out of memory for an internal data structure;
[EADDRINUSE] when an attempt is made to create a socket with a selector which has already been allocated;
[EADDRNOTAVAIL] when an attempt is made to create a socket with a network address for which no network interface exists.
SEE ALSO getsockopt(2), recv(2), send(2), socket(2), clnp(4), intro(4), iso(4)BSD June 9, 1993 BSD