GETSOCKNAME(2)GETSOCKNAME(2)NAMEgetsockname - get socket name
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
int getsockname (int s, struct sockaddr *name, socklen_t *namelen);
#if _XOPEN_SOURCE >= 500
int getsockname (int s, struct sockaddr *name, socklen_t *namelen);
#elif _XOPEN_SOURCE < 500
int getsockname (int s, struct sockaddr *name, size_t *namelen);
#endif
DESCRIPTION
Getsockname returns the current name for the specified socket. The
namelen parameter should be initialized to indicate the amount of space
pointed to by name. On return it contains the actual size of the name
returned (in bytes).
DIAGNOSTICS
A 0 is returned if the call succeeds, -1 if it fails.
ERRORS
The call succeeds unless:
[EBADF] The argument s is not a valid descriptor.
[ENOTSOCK] The argument s is a file, not a socket.
[ENOBUFS] Insufficient resources were available in the system to
perform the operation.
[EFAULT] The name parameter points to memory not in a valid part of
the process address space.
SEE ALSObind(2), socket(2), getpeername(2)NOTES
ABI-compliant versions of the above call can be obtained from
libsocket.so.
This call does not return useful results when used on sockets of type
AF_UNIX, unless the socket was explicitly bound to a pathname.
There are three types of getsockname functions in n32 and 64 bit C
libraries for IRIX 6.5.19 and later versions. One is the normal type when
_XOPEN_SOURCE is not defined; the second is XPG5 type when _XOPEN_SOURCE
is set to >= 500; and the third is XPG4 type when _XOPEN_SOURCE set to <
500. The difference between these functions is in the third argument
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GETSOCKNAME(2)GETSOCKNAME(2)
type to getsockname. Refer <sys/socket.h> for alternate definitions of
socklen_t type.
1. For the normal case when _XOPEN_SOURCE is not defined, third
argument type, a pointer to a socklen_t type, will actually be a
pointer to an int and the normal getsockname is used.
2. When _XOPEN_SOURCE is set to >= 500, third argument type, a
pointer to a socklen_t type, will actually be a pointer to a
u_int32_t type and xpg5 type function will be used.
3. When _XOPEN_SOURCE is set to < 500, third argument type will be a
pointer to a size_t and xpg4 type function will be used.
XPG5 type function is not supported in o32 C library.
The XPG5 type getsockname function is actually defined as a static inline
function in <sys/socket.h>, and it calls a new function _xpg5_getsockname
which is specific to IRIX 6.5.19 and later. Therefore applications that
call XPG5 type getsockname should check the existence of the new symbol.
#include <sys/socket.h>
#include <optional_sym.h>
if (_MIPS_SYMBOL_PRESENT(_xpg5_getsockname)) {
getsockname(s, &name, &namelen);
} else {
...
}
Because the static inline function is defined in each source file that
includes <sys/socket.h>, these static functions will have different
addresses in any cases that inline expansion is not performed. This may
cause problems if the address of the function is examined in programs.
To avoid this problem, use -D_XPG5_GETSOCKNAME_USER_DEFINED compile
option to disable the static inline definition in <sys/socket.h>, and
define a user defined function with below definition:
int *
getsockname(int _s, struct sockaddr *_name, socklen_t *_namelen)
{
return(_xpg5_getsockname(_s, _name, _namelen));
}
Use the compile option always, when a user defined XPG5 getsockname
function is required.
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