Ubuntu Manpage: nng_listener_getopt

NAME

       nng_listener_getopt - get listener option

SYNOPSIS

           #include <nng/nng.h>

           int nng_listener_getopt(nng_listener l, const char *opt, void *val, size_t *valszp);

           int nng_listener_getopt_bool(nng_listener l, const char *opt, bool *bvalp);

           int nng_listener_getopt_int(nng_listener l, const char *opt, int *ivalp);

           int nng_listener_getopt_ms(nng_listener l, const char *opt, nng_duration *durp);

           int nng_listener_getopt_ptr(nng_listener l, const char *opt, void **ptr);

           int nng_listener_getopt_size(nng_listener l, const char *opt, size_t *zp);

           int nng_listener_getopt_sockaddr(nng_listener l, const char *opt, nng_sockaddr *sap);

           int nng_listener_getopt_string(nng_listener l, const char *opt, char **strp);

           int nng_listener_getopt_uint64(nng_listener l, const char *opt, uint64_t *u64p);

DESCRIPTION

           Important
           These functions are deprecated. Please see nng_listener_get. They may not be present
           if the library was built with NNG_ELIDE_DEPRECATED.

       The nng_listener_getopt() functions are used to retrieve option values for the listener l.
       The actual options that may be retrieved in this way vary, and many are documented in
       nng_options(5).

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

   Forms
       In all of these forms, the option opt is retrieved from the listener l. The forms vary
       based on the type of the option they take.

       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_getopt()
           This function is untyped and can be used to retrieve the value of any option. The
           caller must store a pointer to a buffer to receive the value in val, and the size of
           the buffer shall be stored at the location referenced by valszp.

           When the function returns, the actual size of the data copied (or that would have been
           copied if sufficient space were present) is stored at the location referenced by
           valszp. If the caller’s buffer is not large enough to hold the entire object, then the
           copy is truncated. Therefore the caller should validate that the returned size in
           valszp does not exceed the original buffer size to check for truncation.

           It is acceptable to pass NULL for val if the value in valszp is zero. This can be used
           to determine the size of the buffer needed to receive the object.

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

       nng_listener_getopt_bool()
           This function is for options which take a Boolean (bool). The value will be stored at
           bvalp.

       nng_listener_getopt_int()
           This function is for options which take an integer (int). The value will be stored at
           ivalp.

       nng_listener_getopt_ms()
           This function is used to retrieve time durations (such as timeouts), stored in durp as
           a number of milliseconds.

       nng_listener_getopt_ptr()
           This function is used to retrieve a pointer, ptr, to structured data. The data
           referenced by ptr is generally managed using other functions. Note that this form is
           somewhat special in that the object is generally not copied, but instead the pointer
           to the object is copied.

       nng_listener_getopt_size()
           This function is used to retrieve a size into the pointer zp, typically for buffer
           sizes, message maximum sizes, and similar options.

       nng_listener_getopt_sockaddr()
           This function is used to retrieve an nng_sockaddr into the value referenced by sap.

       nng_listener_getopt_string()
           This function is used to retrieve a string into strp. This string is created from the
           source using nng_strdup() and consequently must be freed by the caller using
           nng_strfree() when it is no longer needed.

       nng_listener_getopt_uint64()
           This function is used to retrieve a 64-bit unsigned value into the value referenced by
           u64p. This is typically used for options related to identifiers, network numbers, and
           similar.

RETURN VALUES

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

ERRORS

       NNG_EBADTYPE
           Incorrect type for option.

       NNG_ECLOSED
           Parameter l does not refer to an open listener.

       NNG_EINVAL
           Size of destination val too small for object.

       NNG_ENOMEM
           Insufficient memory exists.

       NNG_ENOTSUP
           The option opt is not supported.

       NNG_EWRITEONLY
           The option opt is write-only.

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUES

ERRORS

SEE ALSO