This documentation is for version v1.3.0 of NNG, but the latest released version is v1.8.0. see the documentation for v1.8.0 for the most up-to-date information.


#include <nng/nng.h>

int nng_stream_set(nng_stream *s, const char *name, const void *data, size_t size);

int nng_stream_set_bool(nng_stream *s, const char *opt, bool val);

int nng_stream_set_int(nng_stream *s, const char *opt, int val);

int nng_stream_set_ms(nng_stream *s, const char *opt, nng_duration val);

int nng_stream_set_ptr(nng_stream *s, const char *opt, void *val);

int nng_stream_set_size(nng_stream *s, const char *opt, size_t val);

int nng_stream_set_string(nng_stream *s, const char *opt, const char *val);

int nng_stream_set_uint64(nng_stream *s, const char *opt, uint64_t val);

int nng_stream_set_addr(nng_stream *s, const char *opt, const nng_sockaddr *val);


The nng_stream_set() functions are used to configure options for the byte stream s. The actual options that may be configured in this way vary, and are specified by opt. A number of them are documented in nng_options(5).

Additionally some transport-specific and protocol-specific options are documented with the transports and protocols themselves.


The details of the type, size, and semantics of the option will depend on the actual option, and will be documented with the option itself.


This function is untyped, and can be used to configure any arbitrary data. The val pointer addresses the data to copy, and size is the size of the objected located at val.

It may be easier to use one of the typed forms of this function.

This function is for options which take a Boolean (bool).


This function is for options which take an integer (int).


This function is used to configure time durations (such as timeouts) using the type nng_duration. The duration is an integer number of milliseconds.


This function is used to pass a pointer to structured data. The data referenced by is generally managed by other functions. For example, TLS configuration objects created with nng_tls_config_alloc() can be passed this way.

This form is somewhat special in that the object is generally not copied, but instead the pointer to the object is copied. Please see the documentation for the specific option for further details.

This function is used to configure a size, typically for buffer sizes, message maximum sizes, and similar options.


This function is used to pass configure a string. Strings passed this way must be legal UTF-8 or ASCII strings, terminated with a NUL (0) byte. (Other constraints may apply as well, see the documentation for each option for details.)


This function is used to configure a 64-bit unsigned value/ This is typically used for identifiers, network numbers, and similar options.


This function is used to configure a socket address. The value is copied, and thus the caller may discard the supplied value immediately after this function returns.


This function returns 0 on success, and non-zero otherwise.



The connection is closed.


Either data or size are invalid.


The option is not supported.


The option may not be modified.