From 5cf750697624d4fd63cfe26921209d7c30e1a2d2 Mon Sep 17 00:00:00 2001 From: Garrett D'Amore Date: Mon, 21 Jan 2019 22:40:10 -0800 Subject: fixes #872 create unified nng_stream API This is a major change, and includes changes to use a polymorphic stream API for all transports. There have been related bugs fixed along the way. Additionally the man pages have changed. The old non-polymorphic APIs are removed now. This is a breaking change, but the old APIs were never part of any released public API. --- docs/man/nng_stream_get.3str.adoc | 146 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 146 insertions(+) create mode 100644 docs/man/nng_stream_get.3str.adoc (limited to 'docs/man/nng_stream_get.3str.adoc') diff --git a/docs/man/nng_stream_get.3str.adoc b/docs/man/nng_stream_get.3str.adoc new file mode 100644 index 00000000..9a2b0220 --- /dev/null +++ b/docs/man/nng_stream_get.3str.adoc @@ -0,0 +1,146 @@ += nng_stream_get(3str) +// +// Copyright 2019 Staysail Systems, Inc. +// Copyright 2018 Capitar IT Group BV +// Copyright 2019 Devolutions +// +// This document is supplied under the terms of the MIT License, a +// copy of which should be located in the distribution where this +// file was obtained (LICENSE.txt). A copy of the license may also be +// found online at https://opensource.org/licenses/MIT. +// + +== NAME + +nng_stream_get - get option from byte stream + +== SYNOPSIS + +[source, c] +---- +#include + +int nng_stream_get(nng_stream *s, const char *opt, void *val, size_t *sizep); + +int nng_stream_get_bool(nng_stream *s, const char *opt, bool *valp); + +int nng_stream_get_int(nng_stream *s, const char *opt, int *valp); + +int nng_stream_get_ms(nng_stream *s, const char *opt, nng_duration *valp); + +int nng_stream_get_ptr(nng_stream *s, const char *opt, void **valp); + +int nng_stream_get_size(nng_stream *s, const char *opt, size_t *valp); + +int nng_stream_get_addr(nng_stream *s, const char *opt, nng_sockaddr *valp); + +int nng_stream_get_string(nng_stream *s, const char *opt, char **valp); + +int nng_stream_get_uint64(nng_stream *s, const char *opt, uint64_t *valp); + +---- + +== DESCRIPTION + +The `nng_stream_get()` functions are used to retrieve option values for the +xref:nng_stream.5.adoc[byte stream] _conn_. + +The actual options that may be retrieved in this way vary. +A number of them are documented in +xref:nng_options.5.adoc[nng_options(5)] and additional linked documents. + +=== Forms + +In all of these forms, the option _opt_ is retrieved from the connected +byte stream _s_. +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_stream_get()`:: +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 +_sizep_. ++ +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 _sizep_. +If the caller's buffer is not large enough to hold the entire object, +then the copy is truncated. +Therefore the caller should check for truncation by verifying that the +returned size in _sizep_ does not exceed the original buffer size. ++ +It is acceptable to pass `NULL` for _val_ if the value in _sizep_ 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_stream_get_bool()`:: +This function is for options which take a Boolean (`bool`). + +`nng_stream_get_int()`:: +This function is for options which take an integer (`int`). + +`nng_stream_get_ms()`:: +This function is used to retrieve time +xref:nng_duration.5.adoc[durations] +(such as timeouts), stored as a number of milliseconds. +(The special value ((`NNG_DUR_INFINITE`)) means an infinite amount of time, and +the special value ((`NNG_DUR_DEFAULT`)) means a context-specific default.) + +`nng_stream_get_ptr()`:: +This function is used to retrieve a pointer to structured data. +The data referenced 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. ++ +NOTE: Care must be taken to ensure that the application respects any +considerations about the lifetime of the underyling object. +See the documentation for the option for more specific guidance. + +`nng_stream_get_size()`:: +This function is used to retrieve a size, +typically for buffer sizes, message maximum sizes, and similar options. + +`nng_stream_get_addr()`:: +This function is used to retrieve a +xref:nng_sockaddr.5.adoc[socket address]. + +`nng_stream_get_string()`:: +This function is used to retrieve a `NULL`-terminated string. +This string is created from the source using +xref:nng_strdup.3.adoc[`nng_strdup()`] +and consequently must be freed by the caller using +xref:nng_strfree.3.adoc[`nng_strfree()`] when it is no longer needed. + +`nng_stream_get_uint64()`:: +This function is used to retrieve a 64-bit unsigned value. +This is typically used for identifiers, network +numbers, and similar options. + +== RETURN VALUES + +This function returns 0 on success, and non-zero otherwise. + +== ERRORS + +[horizontal] +`NNG_ECLOSED`:: The connection is closed. +`NNG_EINVAL`:: There was insufficient space to receive the object. + The amount of data actually needed is returned in _sizep_. +`NNG_ENOTSUP`:: The option is not supported. +`NNG_EWRITEONLY`:: The option may not read. + +== SEE ALSO + +[.text-left] +xref:nng_strerror.3.adoc[nng_strerror(3)], +xref:nng_stream_set.3str.adoc[nng_stream_set(3str)], +xref:nng_options.5.adoc[nng_options(5)], +xref:nng_ipc_options.5.adoc[nng_ipc_options(5)], +xref:nng_tcp_options.5.adoc[nng_tcp_options(5)], +xref:nng_tls_options.5.adoc[nng_tls_options(5)], +xref:nng_stream.5.adoc[nng_stream(5)] -- cgit v1.2.3-70-g09d2