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'\" t
.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: GPL-2.0-or-later
.\"
.TH socketcall 2 2025-09-21 "Linux man-pages (unreleased)"
.SH NAME
socketcall \- socket system calls
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.BR "#include <linux/net.h>" " /* Definition of " SYS_* " constants */"
.BR "#include <sys/syscall.h>" " /* Definition of " SYS_socketcall " */"
.B #include <unistd.h>
.P
.BI "int syscall(SYS_socketcall, int " call ", unsigned long *" args );
.fi
.P
.IR Note :
glibc provides no wrapper for
.BR socketcall (),
necessitating the use of
.BR syscall (2).
.SH DESCRIPTION
.BR socketcall ()
is a common kernel entry point for the socket system calls.
.I call
determines which socket function to invoke.
.I args
points to a block containing the actual arguments,
which are passed through to the appropriate call.
.P
User programs should call the appropriate functions by their usual names.
Only standard library implementors and kernel hackers need to know about
.BR socketcall ().
.P
.TS
tab(:);
l l.
\f[I]call\f[]:Man page
T{
.B SYS_SOCKET
T}:T{
.BR socket (2)
T}
T{
.B SYS_BIND
T}:T{
.BR bind (2)
T}
T{
.B SYS_CONNECT
T}:T{
.BR connect (2)
T}
T{
.B SYS_LISTEN
T}:T{
.BR listen (2)
T}
T{
.B SYS_ACCEPT
T}:T{
.BR accept (2)
T}
T{
.B SYS_GETSOCKNAME
T}:T{
.BR getsockname (2)
T}
T{
.B SYS_GETPEERNAME
T}:T{
.BR getpeername (2)
T}
T{
.B SYS_SOCKETPAIR
T}:T{
.BR socketpair (2)
T}
T{
.B SYS_SEND
T}:T{
.BR send (2)
T}
T{
.B SYS_RECV
T}:T{
.BR recv (2)
T}
T{
.B SYS_SENDTO
T}:T{
.BR sendto (2)
T}
T{
.B SYS_RECVFROM
T}:T{
.BR recvfrom (2)
T}
T{
.B SYS_SHUTDOWN
T}:T{
.BR shutdown (2)
T}
T{
.B SYS_SETSOCKOPT
T}:T{
.BR setsockopt (2)
T}
T{
.B SYS_GETSOCKOPT
T}:T{
.BR getsockopt (2)
T}
T{
.B SYS_SENDMSG
T}:T{
.BR sendmsg (2)
T}
T{
.B SYS_RECVMSG
T}:T{
.BR recvmsg (2)
T}
T{
.B SYS_ACCEPT4
T}:T{
.BR accept4 (2)
T}
T{
.B SYS_RECVMMSG
T}:T{
.BR recvmmsg (2)
T}
T{
.B SYS_SENDMMSG
T}:T{
.BR sendmmsg (2)
T}
.TE
.SH VERSIONS
On some architectures
\[em]for example, x86-64 and ARM\[em]
there is no
.BR socketcall ()
system call;
instead
.BR socket (2),
.BR accept (2),
.BR bind (2),
and so on really are implemented as separate system calls.
.SH STANDARDS
Linux.
.P
On x86-32,
.BR socketcall ()
was historically the only entry point for the sockets API.
However, starting in Linux 4.3,
.\" commit 9dea5dc921b5f4045a18c63eb92e84dc274d17eb
direct system calls are provided on x86-32 for the sockets API.
This facilitates the creation of
.BR seccomp (2)
filters that filter sockets system calls
(for new user-space binaries that are compiled
to use the new entry points)
and also provides a (very) small performance improvement.
.SH SEE ALSO
.BR accept (2),
.BR bind (2),
.BR connect (2),
.BR getpeername (2),
.BR getsockname (2),
.BR getsockopt (2),
.BR listen (2),
.BR recv (2),
.BR recvfrom (2),
.BR recvmsg (2),
.BR send (2),
.BR sendmsg (2),
.BR sendto (2),
.BR setsockopt (2),
.BR shutdown (2),
.BR socket (2),
.BR socketpair (2)
|
