Scroll to navigation

SOCKETCALL(2) Linux Programmer's Manual SOCKETCALL(2)


socketcall - socket system calls


#include <linux/net.h>        /* Definition of SYS_* constants */
#include <sys/syscall.h>      /* Definition of SYS_socketcall */
#include <unistd.h>
int syscall(SYS_socketcall, int call, unsigned long *args);

Note: glibc provides no wrapper for socketcall(), necessitating the use of syscall(2).


socketcall() is a common kernel entry point for the socket system calls. call determines which socket function to invoke. args points to a block containing the actual arguments, which are passed through to the appropriate call.

User programs should call the appropriate functions by their usual names. Only standard library implementors and kernel hackers need to know about socketcall().

call Man page
SYS_SOCKET socket (2)
SYS_BIND bind (2)
SYS_CONNECT connect (2)
SYS_LISTEN listen (2)
SYS_ACCEPT accept (2)
SYS_GETSOCKNAME getsockname (2)
SYS_GETPEERNAME getpeername (2)
SYS_SOCKETPAIR socketpair (2)
SYS_SEND send (2)
SYS_RECV recv (2)
SYS_SENDTO sendto (2)
SYS_RECVFROM recvfrom (2)
SYS_SHUTDOWN shutdown (2)
SYS_SETSOCKOPT setsockopt (2)
SYS_GETSOCKOPT getsockopt (2)
SYS_SENDMSG sendmsg (2)
SYS_RECVMSG recvmsg (2)
SYS_ACCEPT4 accept4 (2)
SYS_RECVMMSG recvmmsg (2)
SYS_SENDMMSG sendmmsg (2)


This call is specific to Linux, and should not be used in programs intended to be portable.


On some architectures—for example, x86-64 and ARM—there is no socketcall() system call; instead socket(2), accept(2), bind(2), and so on really are implemented as separate system calls.

On x86-32, socketcall() was historically the only entry point for the sockets API. However, starting in Linux 4.3, direct system calls are provided on x86-32 for the sockets API. This facilitates the creation of 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.


accept(2), bind(2), connect(2), getpeername(2), getsockname(2), getsockopt(2), listen(2), recv(2), recvfrom(2), recvmsg(2), send(2), sendmsg(2), sendto(2), setsockopt(2), shutdown(2), socket(2), socketpair(2)


This page is part of release 5.13 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

2021-03-22 Linux