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ACCF_DATA(9) | 
Kernel Developer's Manual | 
ACCF_DATA(9) | 
NAME
 accf_data — buffer incoming connections until data arrives
SYNOPSIS
 options INET
pseudo-device accf_data
DESCRIPTION
 This is a filter to be placed on a socket that will be using 
accept() to receive incoming connections.
It prevents the application from receiving the connected descriptor via accept() until data arrives on the connection.
 
EXAMPLES
 If the 
accf_data accept filter is present in the kernel configuration, this will enable the data accept filter on the socket 
sok.
	struct accept_filter_arg afa; 
 
	bzero(&afa, sizeof(afa)); 
	strcpy(afa.af_name, "dataready"); 
	setsockopt(sok, SOL_SOCKET, SO_ACCEPTFILTER, &afa, sizeof(afa));
 
HISTORY
 The accept filter mechanism and the accf_data filter were introduced in FreeBSD 4.0. They were ported to NetBSD by Coyote Point Systems and appeared in NetBSD 5.0.
AUTHORS
 This manual page and the filter were written by Alfred Perlstein.