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NOTE: This documentation is for version 0.2.0 of nng, but the latest released version is 1.1.0. Please see the documentation for 1.1.0 for the most up-to-date information.


#include <nng/transport/inproc/inproc.h>

int nng_inproc_register(void);


The nng_inproc transport provides communication support between nng sockets within the same process. This may be used as an alternative to slower transports when data must be moved within the same process.

This transport tries hard to avoid copying data, and thus is very light-weight.


The inproc transport is generally built-in to the nng core, so no extra steps to use it should be necessary.

URI Format

This transport uses URIs using the scheme inproc://, followed by an arbitrary string of text, terminated by a NUL byte.

Multiple URIs can be used within the same application, and they will not interfere with one another.

Two applications may also use the same URI without interfering with each other, and they will be unable to communicate with each other using that URI.

Socket Address

When using an nng_sockaddr structure, the actual structure is of type struct nng_sockaddr_inproc. This type has the following definition:

#define NNG_AF_INPROC 1 (1)
#define NNG_MAXADDRLEN 128

typedef nng_sockaddr_inproc {
    uint16_t sa_family;                  // must be NNG_AF_INPROC
    char     sa_path[NNG_MAXADDRLEN];    // arbitrary "path"
1 The values of these macros may change, so applications should avoid depending upon their values and instead use them symbolically.
2 Other members may be present, but only those listed here are suitable for application use.

The sa_family member will have the value NNG_AF_INPROC. The sa_path member is an ASCIIZ string, and may contain any characters, terminated by a NUL byte.

Transport Options

The inproc transport has no special options.


NNG Reference Manual v0.2.0 © 2018 Staysail Systems, Inc, © 2018 Capitar IT Group BV
This document is supplied under the MIT License.
nanomsg™ and nng™ are trademarks of Garrett D'Amore.