UI_CREATE_METHOD(3ossl)

📦

version 3.5.9 · 8 versions

3.5.9 · fedora 43, fedora 44 (latest)
3.5.9 · centos-stream 9
3.5.9 · centos-stream 10
3.5.9 · alpine 3.22
3.5.9 · alpine 3.23, alpine 3.24
3.5.8 · fedora 43
3.5.1 · fedora 43
3.5.5 · fedora 44

✨ NAME ✨

okay bestie so this whole page is about the user interface method creation and destruction squad 💖 — like, all the little functions that build and poke at a UI_METHOD:

UI_METHOD
UI_create_method
UI_destroy_method
UI_method_set_opener
UI_method_set_writer
UI_method_set_flusher
UI_method_set_reader
UI_method_set_closer
UI_method_set_data_duplicator
UI_method_set_prompt_constructor
UI_method_set_ex_data
UI_method_get_opener
UI_method_get_writer
UI_method_get_flusher
UI_method_get_reader
UI_method_get_closer
UI_method_get_data_duplicator
UI_method_get_data_destructor
UI_method_get_prompt_constructor
UI_method_get_ex_data

and yeah, it's literally called "user interface method creation and destruction". iconique 🎀

🌸 SYNOPSIS 🌸

#include <openssl/ui.h>

typedef struct ui_method_st UI_METHOD;

UI_METHOD *UI_create_method(const char *name);
void UI_destroy_method(UI_METHOD *ui_method);
int UI_method_set_opener(UI_METHOD *method, int (*opener) (UI *ui));
int UI_method_set_writer(UI_METHOD *method,
                         int (*writer) (UI *ui, UI_STRING *uis));
int UI_method_set_flusher(UI_METHOD *method, int (*flusher) (UI *ui));
int UI_method_set_reader(UI_METHOD *method,
                         int (*reader) (UI *ui, UI_STRING *uis));
int UI_method_set_closer(UI_METHOD *method, int (*closer) (UI *ui));
int UI_method_set_data_duplicator(UI_METHOD *method,
                                  void *(*duplicator) (UI *ui, void *ui_data),
                                  void (*destructor)(UI *ui, void *ui_data));
int UI_method_set_prompt_constructor(UI_METHOD *method,
                                     char *(*prompt_constructor) (UI *ui,
                                                                  const char
                                                                  *object_desc,
                                                                  const char
                                                                  *object_name));
int UI_method_set_ex_data(UI_METHOD *method, int idx, void *data);
int (*UI_method_get_opener(const UI_METHOD *method)) (UI *);
int (*UI_method_get_writer(const UI_METHOD *method)) (UI *, UI_STRING *);
int (*UI_method_get_flusher(const UI_METHOD *method)) (UI *);
int (*UI_method_get_reader(const UI_METHOD *method)) (UI *, UI_STRING *);
int (*UI_method_get_closer(const UI_METHOD *method)) (UI *);
char *(*UI_method_get_prompt_constructor(const UI_METHOD *method))
    (UI *, const char *, const char *);
void *(*UI_method_get_data_duplicator(const UI_METHOD *method)) (UI *, void *);
void (*UI_method_get_data_destructor(const UI_METHOD *method)) (UI *, void *);
const void *UI_method_get_ex_data(const UI_METHOD *method, int idx);

🦋 DESCRIPTION 🦋

so a method is basically a little bundle of functions that does the low-level grunt work of the User Interface. and the functions in the bundle are, drumroll please 🥁:

the five main characters 💅

an opener — takes a reference to a UI and starts a session. like, opening a channel to a tty, or popping up a dialog box. main character energy fr.
a writer — takes a reference to a UI and a UI String, then writes that string wherever it belongs — maybe to the tty, maybe as a field label in a dialog box. ⚠️ heads up: this gets fed all the strings associated with a UI, one after the other, so you gotta be careful about which ones it actually uses.
a flusher — takes a reference to a UI and flushes everything that's been output so far. like, if the method is building up a dialog box, this is the moment it actually displays it and takes input that ended with a pressed button. ✨
a reader — takes a reference to a UI and a UI string, and reads off the given prompt — maybe from the tty, maybe from a field in a dialog box. ⚠️ same deal: it gets fed all the strings associated with a UI, one after the other, so care must be taken which ones it actually uses.
a closer — takes a reference to a UI and closes the session. maybe by closing the channel to the tty, maybe by destroying a dialog box. bye bestie 👋

all of these functions are expected to return 0 on error, 1 on success, or -1 on out-off-band events — like if some prompting got cancelled (pressing Ctrl-C, for example 🙈). and ngl, only the flusher or the reader are expected to return -1. if any of the other functions returns it, it's treated as if 0 was returned. no cap.

about the writer and the reader: don't assume the former should only write, and don't assume the latter should only read. it literally depends on the needs of the method. 🫶

for example, a typical tty reader wouldn't write the prompts in the write, but would rather do so in the reader, because of the sequential nature of prompting on a tty. that's how the UI_OpenSSL() method does it, iykyk.

in contrast, a method that builds up a dialog box would add all prompt text in the writer, have all input read in the flusher and store the results in some temporary buffer, and finally have the reader just fetch those results. the way that works is honestly so satisfying 💜

the central function that uses these method functions is UI_process(), and it does it in five steps:

Open the session using the opener function if that one's defined. If an error occurs, jump to 5.
For every UI String associated with the UI, call the writer function if that one's defined. If an error occurs, jump to 5.
Flush everything using the flusher function if that one's defined. If an error occurs, jump to 5.
For every UI String associated with the UI, call the reader function if that one's defined. If an error occurs, jump to 5.
Close the session using the closer function if that one's defined.

now the actual functions, one by one 🌈

UI_create_method() creates a new UI method with a given name.
UI_destroy_method() destroys the given UI method ui_method.
UI_method_set_opener(), UI_method_set_writer(), UI_method_set_flusher(), UI_method_set_reader() and UI_method_set_closer() set the five main method function to the given function pointer.
UI_method_set_data_duplicator() sets the user data duplicator and destructor. see UI_dup_user_data(3).
UI_method_set_prompt_constructor() sets the prompt constructor. see UI_construct_prompt(3).
UI_method_set_ex_data() sets application specific data with a given EX_DATA index. see CRYPTO_get_ex_new_index(3) for general information on how to get that index.
UI_method_get_opener(), UI_method_get_writer(), UI_method_get_flusher(), UI_method_get_reader(), UI_method_get_closer(), UI_method_get_data_duplicator(), UI_method_get_data_destructor() and UI_method_get_prompt_constructor() return the different method functions.
UI_method_get_ex_data() returns the application data previously stored with UI_method_set_ex_data().

🎀 RETURN VALUES 🎀

UI_create_method() returns a UI_METHOD pointer on success, NULL on error. 💀
UI_method_set_opener(), UI_method_set_writer(), UI_method_set_flusher(), UI_method_set_reader(), UI_method_set_closer(), UI_method_set_data_duplicator() and UI_method_set_prompt_constructor() return 0 on success, -1 if the given method is NULL.
UI_method_set_ex_data() returns 1 on success and 0 on error (because CRYPTO_set_ex_data() does so).
UI_method_get_opener(), UI_method_get_writer(), UI_method_get_flusher(), UI_method_get_reader(), UI_method_get_closer(), UI_method_get_data_duplicator(), UI_method_get_data_destructor() and UI_method_get_prompt_constructor() return the requested function pointer if it's set in the method, otherwise NULL.
UI_method_get_ex_data() returns a pointer to the application specific data associated with the method. ✨

👑 SEE ALSO 👑

🌟 HISTORY 🌟

the UI_method_set_data_duplicator(), UI_method_get_data_duplicator() and UI_method_get_data_destructor() functions were added in OpenSSL 1.1.1. they're new-ish but they ate 💅

💖 COPYRIGHT 💖

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.

and that's the whole page bestie, no skips, no cuts, every single detail preserved 🫶 go forth and build ur UI methods, you're literally the main character of this tty 🌈

okay bye ily — this was page UI_CREATE_METHOD(3ossl) from OpenSSL 3.5.9, dated 2026-09-29. periodt. 💖✨🎀

📦 where this page comes from

fedora 43: openssl-devel 1:3.5.9-1.fc43 · Apache-2.0
fedora 43: openssl-devel 1:3.5.9-1.fc43 · Apache-2.0
fedora 44: openssl-devel 1:3.5.9-1.fc44 · Apache-2.0
fedora 44: openssl-devel 1:3.5.9-1.fc44 · Apache-2.0
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-10-14: a language model's rewrite of the original, under its terms