doc: nng_url converted to mdbook.

3 files changed, 78 insertions, 0 deletions

diff --git a/docs/ref/SUMMARY.md b/docs/ref/SUMMARY.md
index d19bd8e0..d3272742 100644
--- a/docs/ref/SUMMARY.md
+++ b/docs/ref/SUMMARY.md
@@ -31,6 +31,7 @@
     - [nng_socket_pair](./api/util/nng_socket_pair.md)
     - [nng_strdup](./api/util/nng_strdup.md)
     - [nng_strerror](./api/util/nng_strerror.md)
+    - [nng_url](./api/util/nng_url.md)
     - [nng_version](./api/util/nng_version.md)
 
 - [Transports](./tran/index.md)
diff --git a/docs/ref/api/util/index.md b/docs/ref/api/util/index.md
index 0a3cb891..a4dcbf12 100644
--- a/docs/ref/api/util/index.md
+++ b/docs/ref/api/util/index.md
@@ -15,4 +15,5 @@ of other uses.
 - [nng_socket_pair](nng_socket_pair.md) --- create a connected pair of BSD sockets
 - [nng_strdup](nng_strdup.md) --- duplicate string
 - [nng_strerror](nng_strerror.md) --- return an error description
+- [nng_url](nng_url.md) --- Universal Resource Locator object
 - [nng_version](nng_version.md) --- report library version
diff --git a/docs/ref/api/util/nng_url.md b/docs/ref/api/util/nng_url.md
new file mode 100644
index 00000000..4da2ab97
--- /dev/null
+++ b/docs/ref/api/util/nng_url.md
@@ -0,0 +1,76 @@
+# nng_url
+
+## NAME
+
+nng_url --- Universal Resource Locator object
+
+## SYNOPSIS
+
+```c
+#include <nng/nng.h>
+
+typedef struct nng_url {
+    char *u_rawurl;
+    char *u_scheme;
+    char *u_userinfo;
+    char *u_host;
+    char *u_hostname;
+    char *u_port;
+    char *u_path;
+    char *u_query;
+    char *u_fragment;
+    char *u_requri;
+} nng_url;
+
+int nng_url_parse(nng_url **urlp, const char *str);
+int nng_url_clone(nng_url **dup, nng_url *url);
+void nng_url_free(nng_url *url);
+```
+
+## DESCRIPTION
+
+An {{i:`nng_url`}}{{hi:URL}}{{hi:Universal Resource Locator}} is a structure used for representing URLs.
+These structures are created by parsing string formatted URLs with {{i:`nng_url_parse`}}.
+
+An `nng_url` may be cloned using the {{i:`nng_url_clone`}} function.
+The original _url_ is duplicated into the location specified by _dup_.
+
+When no longer needed, `nng_url` objects may be freed using {{i:`nng_url_free`}}.
+
+> [!IMPORTANT]
+> Only `nng_url_free` should be used to deallocate `nng_url` objects.
+
+### URL Fields
+
+Applications may access individual fields, but must not free or
+alter them, as the underlying memory is managed by the library.
+
+The fields of an `nng_url` object are as follows:
+
+- `u_rawurl`: The unparsed URL string. This will never be `NULL`.
+- `u_scheme`: The URL scheme, such as "http" or "inproc". Always lower case. This will never be `NULL`.
+- `u_userinfo`: This username and password if supplied in the URL string. Will be `NULL` when not present.
+- `u_host`: The full host part of the URL, including the port if present (separated by a colon.)
+- `u_hostname`: The name of the host, and may be the empty string in some cases.
+- `u_port`: The port. May be empty if irrelevant or not specified.
+- `u_path`: The path, typically used with HTTP or WebSockets. Will be empty string if not specified.
+- `u_query`: The query info (typically following `?` in the URL.) Will be `NULL` if not present.
+- `u_fragment`: This is used for specifying an anchor, the part after `#` in a URL. Will be `NULL` if not present.
+- `u_requri`: The full Request-URI. Will be the empty string if not specified.
+
+> [!NOTE]
+> Other fields may also be present, but only those documented here are safe for application use.
+
+> [!TIP]
+> More information about Universal Resource Locators can be found in
+> [RFC 3986](https://tools.ietf.org/html/rfc3986).
+
+## RETURN VALUES
+
+The `nng_url_parse` and `nng_url_clone` functions return zero on success, or a non-zero
+error value.
+
+## ERRORS
+
+- `NNG_ENOMEM`: Insufficient free memory exists.
+- `NNG_EINVAL`: The supplied string does not represent a valid URL.