SYNOPSIS
#include <nng/nng.h>
int nng_listener_setopt(nng_listener l, const char *opt, const void *val,
size_t valsz);
int nng_listener_setopt_int(nng_listener l, const char *opt, int ival);
int nng_listener_setopt_ms(nng_listener l, const char *opt, nng_duration dur);
int nng_listener_setopt_ptr(nng_listener l, const char *opt, void *ptr);
int nng_listener_setopt_size(nng_listener l, const char *opt, size_t z);
int nng_listener_setopt_string(nng_listener l, const char *opt, const char *str);
int nng_listener_setopt_uint64(nng_listener l, const char *opt, uint64_t u64);DESCRIPTION
The nng_listener_setopt() functions are used to configure options for
the listener l. The actual options that may be configured in this way
vary, and are documented in the nng_setopt(3) manual.
Additionally some transport-specific options are documented with the
transports themselves.
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.
The first form of this function, nng_listener_setopt(), 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.
Generally, it will be easier to use one of the typed forms instead.
The second form, nng_listener_setopt_int(),
is for options which take an integer (or boolean). The ival
is passed to the option. For booleans pass either 0 (false) or 1 (true).
The third form, nng_listener_setopt_ms(), is used to configure time durations
(such as timeouts).
The duration dur is an integer number of milliseconds. (The special value
NNG_DUR_INFINITE means an infinite amount of time.)
The fourth form, nng_listener_setopt_ptr(), 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
(nng_tls_config_alloc(3)) can be passed this way.
Note that this form is somewhat special in that the object is generally
not copied, but instead the pointer to the object is copied.
The fifth form, nng_listener_setopt_size(), is used to pass a size
specified by z, typically for buffer sizes, message maximum sizes, and
similar options.
The sixth form, nng_listener_setopt_string(), is used to pass 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 opt for details.)
The seventh form, nng_listener_setopt_uint64(), is used to configure
the 64-bit unsigned value in u64. This is typically used for options
related to identifiers, network numbers, and similar.
| Once a listener has started, it is generally not possible to change it’s configuration. |
RETURN VALUES
This function returns 0 on success, and non-zero otherwise.
ERRORS
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.