UI_STRING(3SSL)

📦

version 4.0.3 · 13 versions

💖 NAME 💖

UI_STRING, UI_string_types, UI_get_string_type, UI_get_input_flags, UI_get0_output_string, UI_get0_action_string, UI_get0_result_string, UI_get_result_string_length, UI_get0_test_string, UI_get_result_minsize, UI_get_result_maxsize, UI_set_result, UI_set_result_ex — it's giving user interface string parsing, bestie 💅

(also it lives in the OpenSSL manuals, which is like... the whole vibe of this page, iykyk 🎀)

🌸 SYNOPSIS 🌸

#include <openssl/ui.h>

typedef struct ui_string_st UI_STRING;

enum UI_string_types {
    UIT_NONE = 0,
    UIT_PROMPT,                 /* Prompt for a string */
    UIT_VERIFY,                 /* Prompt for a string and verify */
    UIT_BOOLEAN,                /* Prompt for a yes/no response */
    UIT_INFO,                   /* Send info to the user */
    UIT_ERROR                   /* Send an error message to the user */
};

enum UI_string_types UI_get_string_type(UI_STRING *uis);
int UI_get_input_flags(UI_STRING *uis);
const char *UI_get0_output_string(UI_STRING *uis);
const char *UI_get0_action_string(UI_STRING *uis);
const char *UI_get0_result_string(UI_STRING *uis);
int UI_get_result_string_length(UI_STRING *uis);
const char *UI_get0_test_string(UI_STRING *uis);
int UI_get_result_minsize(UI_STRING *uis);
int UI_get_result_maxsize(UI_STRING *uis);
int UI_set_result(UI *ui, UI_STRING *uis, const char *result);
int UI_set_result_ex(UI *ui, UI_STRING *uis, const char *result, int len);

🦋 DESCRIPTION 🦋

okay so first thing, bestie — the UI_STRING is not something you build by hand. It gets created internally and added to a UI whenever one of these functions gets called:

UI_add_input_string()
UI_dup_input_string()
UI_add_verify_string()
UI_dup_verify_string()
UI_add_input_boolean()
UI_dup_input_boolean()
UI_add_info_string()
UI_dup_info_string()
UI_add_error_string()
UI_dup_error_string()

If you're a UI_METHOD user, that's literally it, you're done, no need to know more, go live your life 🙈

If you're a UI_METHOD creator though? Now it's interesting 🔥 The whole point is fetching text from these UI_STRING objects, plus adding results back into some of them.

UI_get_string_type() — grabs the type of the UI_STRING you hand it. Type check, but make it cute ✨

UI_get_input_flags() — grabs the flags</> that are chillin' with that given UI_STRING.

UI_get0_output_string() — grabs the actual string you're supposed to output (prompt, info, error, … whatever the vibe is).

UI_get0_action_string() — grabs the action description that's attached to a UIT_BOOLEAN type UI_STRING. For every single other UI_STRING type? You get NULL. Sorry babe 🫶 Go peek at UI_add_input_boolean(3).

UI_get0_result_string() and UI_get_result_string_length() — these two grab the result of a prompt and its length. This is only useful for UIT_PROMPT and UIT_VERIFY type strings, lowkey. For every other UI_STRING type, UI_get0_result_string() returns NULL and UI_get_result_string_length() returns -1. 💀

UI_get0_test_string() — grabs the string you compare the prompt result against. Only useful for UIT_VERIFY type strings. Every other UI_STRING type gets NULL back. Periodt.

UI_get_result_minsize() and UI_get_result_maxsize() — grab the minimum and maximum required size of the result. Only useful for UIT_PROMPT and UIT_VERIFY type strings. For all other UI_STRING types you're getting -1, no notes.

UI_set_result_ex() — sets the result value of a prompt and its length. Here's the tea:

For UIT_PROMPT and UIT_VERIFY type UI strings, this sets the result retrievable with UI_get0_result_string() by copying the contents of result — but only if its length fits the minimum and maximum size requirements.
For UIT_BOOLEAN type UI strings, this sets the first character of the result retrievable with UI_get0_result_string() to the first ok_char given with UI_add_input_boolean() or UI_dup_input_boolean() if the result matched any of them, or to the first of the cancel_chars if the result matched any of them. Otherwise? It's set to the NUL char "\0" and we move on 💅
Wanna know more about ok_chars and cancel_chars? Go read UI_add_input_boolean(3), fr fr.

UI_set_result() does the exact same thing as UI_set_result_ex(), except it calculates the length internally. It expects the string to be terminated with a NUL byte, which is why it's only useful with normal C strings. C strings stay winning ✨

👑 RETURN VALUES 👑

UI_get_string_type() — returns the UI string type.
UI_get_input_flags() — returns the UI string flags.
UI_get0_output_string() — returns the UI string output string.
UI_get0_action_string() — returns the UI string action description string for UIT_BOOLEAN type UI strings, and NULL for any other type.
UI_get0_result_string() — returns the UI string result buffer for UIT_PROMPT and UIT_VERIFY type UI strings, and NULL for any other type.
UI_get_result_string_length() — returns the UI string result buffer's content length for UIT_PROMPT and UIT_VERIFY type UI strings, and -1 for any other type.
UI_get0_test_string() — returns the UI string action description string for UIT_VERIFY type UI strings, and NULL for any other type.
UI_get_result_minsize() — returns the minimum allowed result size for the UI string for UIT_PROMPT and UIT_VERIFY type strings, and -1 for any other type.
UI_get_result_maxsize() — returns the minimum allowed result size for the UI string for UIT_PROMPT and UIT_VERIFY type strings, and -1 for any other type. (yes, it says minimum, that's literally what the page says, no cap 🙈)
UI_set_result() — returns 0 on success, or also 0 when the UI string is of any type other than UIT_PROMPT, UIT_VERIFY or UIT_BOOLEAN. Returns -1 on error.

🌈 SEE ALSO 🌈

UI(3) — go read it, bestie, it's the main character 🫶

🍓 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 a wrap on this page, OpenSSL 4.0.3, dated 2026-09-29 💖 thanks for coming to my ted talk, go write a UI_METHOD and slay 🧚✨

📦 where this page comes from

ubuntu stonking: libssl-doc 4.0.3-1ubuntu1 · Apache-2.0
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-11-03: a language model's rewrite of the original, under its terms