NNG_LISTENER_SET(3) NNG Reference Manual NNG_LISTENER_SET(3)

nng_listener_set - set listener option

#include <nng/nng.h>
int nng_listener_set(nng_listener l, const char *opt, const void *val,
    size_t valsz);
int nng_listener_set_bool(nng_listener l, const char *opt, bool bval);
int nng_listener_set_int(nng_listener l, const char *opt, int ival);
int nng_listener_set_ms(nng_listener l, const char *opt, nng_duration dur);
int nng_listener_set_ptr(nng_listener l, const char *opt, void *ptr);
int nng_listener_set_size(nng_listener l, const char *opt, size_t z);
int nng_listener_set_string(nng_listener l, const char *opt, const char *str);
int nng_listener_set_uint64(nng_listener l, const char *opt, uint64_t u64);

The nng_listener_set() functions are used to configure options for the listener l. The actual options that may be configured in this way vary, and many are documented in nng_options(5).

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


Note

Once a listener has started, it is generally not possible to change
its configuration.

In all of these forms, the option opt is configured on the listener l.

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.

nng_listener_set()

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


Note

This function is deprecated. Use one of the typed functions beelow instead.

nng_listener_set_bool()

This function is for options which take a Boolean (bool). The bval is passed to the option.

nng_listener_set_int()

This function is for options which take an integer (int). The ival is passed to the option.

nng_listener_set_ms()

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

nng_listener_set_ptr()

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


Note

This form is somewhat special in that the object is generally
not copied, but instead the pointer to the object is copied.

nng_listener_set_size()

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

nng_listener_set_string()

This function is used to pass configure a string, str. 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.)

nng_listener_set_uint64()

This function is used to configure a 64-bit unsigned value, u64. This is typically used for options related to identifiers, network numbers, and similar.

These functions return 0 on success, and non-zero otherwise.

NNG_EBADTYPE

Incorrect type for option.

NNG_ECLOSED

Parameter l does not refer to an open listener.

NNG_EINVAL

The value being passed is invalid.

NNG_ENOTSUP

The option opt is not supported.

NNG_EREADONLY

The option opt is read-only.

NNG_ESTATE

The listener l is already started.

nng_listen(3), nng_listener_create(3) nng_listener_get(3) nng_socket_set(3), nng_strerror(3), nng_duration(5), nng_listener(5), nng_options(5), nng(7)

2025-01-05