Added utility function docs

doc/api/httplib_readdir.md

@@ -0,0 +1,29 @@
+# LibHTTP API Reference
+
+### `httplib_readdir( dir );`
+
+### Parameters
+
+| Parameter | Type | Description |
+| :--- | :--- | :--- |
+|**`name`**|`DIR *`| A pointer to name of the directory to open |
+
+### Return Value
+
+| Type | Description |
+| :--- | :--- |
+|`struct dirent *`|A pointer to a directory entry structure or NULL on error|
+
+### Description
+
+The function `httplib_readdir()` reads the next entry from a directory. The directory must have been opened earlier with a call to the function [`httplib_opendir()`](httplib_opendir.md). If the next directory entry can be found, a pointer to a `dirent` structure is returned. If an error occurs or the last item in a directory has been read the value `NULL` is returned instead.
+
+On platforms which support Posix the call to `httplib_readdir()` is a wrapper arround `readdir()`. On other systems the function is implemented with own code as a clone of the `readdir()` function.
+
+After the last item has been read with `httplib_opendir()`, the directory must be closed with a call to [`httplib_closedir()`](httplib_closedir.md) to return occupied resources.
+
+### See Also
+
+* [`httplib_closedir();`](httplib_closedir.md)
+* [`httplib_mkdir();`](httplib_mkdir.md)
+* [`httplib_opendir();`](httplib_opendir.md)