This documentation is for the TIP (development tree) of NNG and may represent unreleased changes or functionality that is experimental, and is subject to change before release. The latest released version is v1.3.2. See the documentation for v1.3.2 for the most up-to-date information.

nng_sockaddr_abstract(5)

NAME

nng_sockaddr_abstract - abstract IPC socket address

SYNOPSIS

#include <nng/nng.h>

enum sockaddr_family {
    NNG_AF_ABSTRACT = 6,
};

typedef struct {
    uint16_t sa_family;
    uint16_t sa_len;
    char     sa_name[107];
} nng_sockaddr_abstract;

DESCRIPTION

An nng_sockaddr_abstract is the flavor of nng_sockaddr used to represent addresses associated with IPC communication using “abstract” sockets.

Abstract sockets are only supported on Linux at present. These sockets have a name that is simply an array of bytes, with no special meaning. Abstract sockets also have no presence in the file system, do not honor any permissions, and are automatically cleaned up by the operating system when no longer in use.

Support for abstract sockets is a new feature in NNG, and it is only available on Linux. As such their use is not recommended for portable applications.

The following structure members are present:

sa_family

This field will always have the value NNG_AF_ABSTRACT.

sa_len

This field provides the name of the length stored in sa_name.

sa_name

This field holds the name of the abstract socket. The bytes of name can have any value, including zero.

The name does not include the leading NUL byte used on Linux to discriminate between abstract and path name sockets.

Auto Bind

An empty value (sa_len equal to zero) can be used on listening sockets to request the system allocate a name. On Linux systems, this will result in a name with either 5 or 8 hexadecimal ASCII characters. The name chosen can be obtained by retrieving the NNG_OPT_LOCADDR option on the listening entity.

Because a zero length name is used to indicate auto bind be used, it is impossible to specify an actual empty name. This name are not supported by NNG, although the underlying system can support it. The use of that name is inadvisable anyway.

SEE ALSO