Very simple pop-up using ncurses form and menu library (not CDK) in C

ncurses-simple-pop-up.c

/*
 * Very simple pop-up using ncurses form and menu library (not CDK).
 *
 * The buttons are made from items and the fields are made from... well fields.
 *
 * How to run:
 *	gcc -o test -lmenu -lform -lncurses ncurses-simple-pop-up.c -g && ./test
 */

// Depending on your OS you might need to remove 'ncurses/' from the include path.
#include <ncurses/form.h>
#include <ncurses/menu.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>

/*

 +-------------------------------+ <-- win_body
 |+-----------------------------+|
 ||                             ||
 ||                             ||
 ||          win_form           ||
 ||                             ||
 ||                             ||
 |+-----------------------------+|
 |+-----------------------------+|
 ||          win_menu           ||
 |+-----------------------------+|
 +-------------------------------+

 */

WINDOW *win_body, *win_form, *win_menu;
FORM *form;
FIELD **fields;
MENU *menu;
ITEM **items;
bool is_on_button; // Used to know the "case" we're in

void new_popup(int rows, int cols, int posy, int posx, char **buttons,
		int nb_buttons, char **requests, int nb_fields)
{
	int i, cury = 0, curx = 1, tmp;
	WINDOW *inner;

	win_body = newwin(rows, cols, posy, posx);
	assert(win_body != NULL);
	box(win_body, 0, 0);

	items = malloc(sizeof(ITEM *) * (nb_buttons+1));
	assert(items);

	for (i = 0; i < nb_buttons; i++) {
		items[i] = new_item(buttons[i], "");
		assert(items[i] != NULL);
	}

	items[i] = NULL;
	menu = new_menu(items);
	win_menu = derwin(win_body, 3, cols-2, rows-4, 1);
	assert(menu != NULL && win_menu != NULL);
	box(win_menu, 0, 0);
	set_menu_win(menu, win_menu);
	set_menu_format(menu, 1, nb_buttons);
	tmp = menu->fcols * (menu->namelen + menu->spc_rows);
	tmp--;
	inner = derwin(win_menu, 1, tmp, 1, (cols-3-tmp)/2);
	assert(inner != NULL);
	set_menu_sub(menu, inner);
	set_menu_mark(menu, "");

	fields = malloc(sizeof(FIELD *) * (nb_fields+1));
	assert(fields);

	for (i = 0; i < nb_fields; i++) {
		fields[i] = new_field(1, 10, cury, curx, 0, 0);
		assert(fields[i] != NULL);
		set_field_buffer(fields[i], 0, requests[i]);

		if (i % 2 == 1) {
			cury = cury+1;
			curx = 1;
			field_opts_on(fields[i], O_ACTIVE);
			field_opts_on(fields[i], O_EDIT);
			set_field_back(fields[i], A_UNDERLINE); 
		} else {
			curx = 20;
			field_opts_off(fields[i], O_ACTIVE);
			field_opts_off(fields[i], O_EDIT);
		}
	}

	fields[i] = NULL;
	form = new_form(fields);
	assert(form != NULL);
	win_form = derwin(win_body, rows-5, cols-2, 1, 1);
	box(win_form, 0, 0);
	assert(form != NULL && win_form != NULL);
	set_form_win(form, win_form);
	inner = derwin(win_form, form->rows+1, form->cols+1, 1, 1);
	assert(inner != NULL);
	set_form_sub(form, inner);

	assert(post_form(form) == E_OK);
	assert(post_menu(menu) == E_OK);
	is_on_button = true;
	pos_menu_cursor(menu);
}

void delete_popup(void)
{
	int i;

	unpost_form(form);
	unpost_menu(menu);

	for (i = 0; fields[i] != NULL; i++) {
		free_field(fields[i]);
	}

	for (i = 0; items[i] != NULL; i++) {
		free_item(items[i]);
	}

	free_menu(menu);
	free_form(form);
	delwin(win_form);
	delwin(win_menu);
	delwin(win_body);
}

/*
 * Actions for 'return' on a button
 */
void driver_buttons(ITEM *item)
{
	const char *name = item_name(item);
	int i;

	if (strcmp(name, "OK") == 0) {
		mvprintw(LINES-2, 1, "[*] OK clicked:\t");

		for (i = 0; i < form->maxfield; i++) {
			printw("%s", field_buffer(fields[i], 0));

			if (field_opts(fields[i]) & O_ACTIVE)
				printw("\t");
		}

	} else if (strcmp(name, "QUIT") == 0)
		mvprintw(LINES-2, 1, "[*] QUIT clicked, 'F1' to quit\n");
	
	refresh();
}

/*
 * When you want to change between the form and the buttons
 */
void switch_to_buttons(void)
{
	// Those 2 lines allow the field buffer to be set
	form_driver(form, REQ_PREV_FIELD);
	form_driver(form, REQ_NEXT_FIELD);

	menu_driver(menu, REQ_FIRST_ITEM);
	is_on_button = true;
	set_menu_fore(menu, A_REVERSE); // "show" the button
}

void driver(int ch)
{
	switch (ch) {
		case KEY_DOWN:
			if (is_on_button)
				break;

			if (form->current == fields[form->maxfield-1])
				switch_to_buttons();
			else
				form_driver(form, REQ_NEXT_FIELD);
			break;

		case KEY_UP:
			if (is_on_button) {
				is_on_button = false;
				set_menu_fore(menu, A_NORMAL); // "hide" the button
			} else
				form_driver(form, REQ_PREV_FIELD);
			break;

		case KEY_LEFT:
			if (is_on_button)
				menu_driver(menu, REQ_LEFT_ITEM);
			else
				form_driver(form, REQ_LEFT_FIELD);
			break;

		case KEY_RIGHT:
			if (is_on_button)
				menu_driver(menu, REQ_RIGHT_ITEM);
			else
				form_driver(form, REQ_RIGHT_FIELD);
			break;

		case 10:
			if (!is_on_button)
				switch_to_buttons();
			else
				driver_buttons(current_item(menu));

			break;

		default:
			if (!is_on_button)
				form_driver(form, ch);

			break;

	}

	if (is_on_button)
		pos_menu_cursor(menu);
	else
		pos_form_cursor(form);

	wrefresh(win_body);
}

int main()
{
	char *buttons[] = { "OK", "QUIT" };
	char *requests[] = { "Password:", "pass", "Id:", "id" };
	int ch;

	initscr();
	noecho();
	cbreak();
	keypad(stdscr, TRUE);

	new_popup(24, 80, (LINES-25)/2, (COLS-81)/2, buttons, 2, requests, 4);
	refresh();
	wrefresh(win_body);
	wrefresh(win_form);
	wrefresh(win_menu);

	while ((ch = getch()) != KEY_F(1))
		driver(ch);
	
	delete_popup();
	endwin();

	return 0;
}

Thanks.
Your one example is enough to start off with making forms.