resizeterm(3X)

✨ resizeterm(3X) ✨

okay so bestie, welcome to resizeterm(3X) — a Library calls girlie, and she is literally the reason your terminal doesn't fall apart when you drag the window corner. 💅

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🌸 NAME 🌸

is_term_resized, resize_term, resizeterm — the trio that manages the terminal dimensions understood by curses 🦋

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✨ SYNOPSIS ✨

#include <curses.h>

bool is_term_resized(int lines, int columns);
int resize_term(int lines, int columns);
int resizeterm(int lines, int columns);

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💖 DESCRIPTION 💖

So this whole thing is an extension to the curses library, okay? It hands callers a little hook straight into the ncurses data so they can resize windows — and it's primarily for programs running in an X Window terminal (e.g., xterm) when the user goes and changes the terminal's screen size. main character energy fr. 👑

Here's the vibe:

• curses windows cannot extend outside the screen. If the terminal gets shrunk, those curses windows must be shrunk to fit. no cap.
• If the terminal is stretched, rows and/or columns can be added to existing windows. The added cells should match the current attributes of the windows. ✨

Now, if the application has not set up a handler for SIGWINCH when it initializes ncurses (by calling initscr(3X) or newterm(3X)), then ncurses establishes a SIGWINCH handler that notifies the library when a window-resizing event has occurred. 📣 And the library checks for this notification:

• when reading input data,
• when implicitly resuming program mode (e.g., between endwin(3X) and wrefresh(3X)), and
• when explicitly resuming program mode in restartterm(3X).

Once the library has found that the terminal's window-size has changed, it calls resizeterm to update its data structures. slay. 🎀

An application which establishes its own SIGWINCH handler can call resizeterm, but in that case, the library will not see SIGWINCH, and proper layout will rely upon the application. iykyk — you're on your own babe. 🫶

💜 resizeterm

The function resizeterm resizes the standard and current windows (i.e., stdscr and curscr) to the specified dimensions, and adjusts other bookkeeping data used by the ncurses library that record the window dimensions such as the LINES and COLS variables. she's the one keeping receipts. 🧾✨

🌈 resize_term

Most of the work for resizeterm is done by the inner function resize_term. The outer function resizeterm adds bookkeeping for the SIGWINCH handler, as well as repainting the soft-key area (see slk_touch(3X)).

The resize_term function attempts to resize all windows. This helps with simple applications. However:

• It is not possible to automatically resize pads. 💀
• Applications which have complicated layouts should check for KEY_RESIZE returned from wgetch, and adjust their layout, e.g., using wresize and mvwin, or by recreating the windows.

When resizing windows, resize_term recursively adjusts subwindows, keeping them within the updated parent window's limits. And if a top-level window happens to extend to the screen's limits, then on resizing the window, resize_term will keep the window extending to the corresponding limit, regardless of whether the screen has shrunk or grown. she's loyal like that. 🥹💖

🦋 is_term_resized

A support function is_term_resized is provided so that applications can check if the resize_term function would modify the window structures. It returns TRUE if the windows would be modified, and FALSE otherwise. a little vibe check, if you will. ✅❌

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⭐ RETURN VALUE ⭐

Except as noted, these functions return the integer ERR upon failure and OK on success. They will fail if either of the dimensions are less than or equal to zero, or if an error occurs while (re)allocating memory for the windows. 😭

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🎀 NOTES 🎀

While these functions are intended to be used to support a signal handler (i.e., for SIGWINCH), care should be taken to avoid invoking them in a context where malloc or realloc may have been interrupted, since it uses those functions. like pls be careful, bestie. 🙈

If ncurses is configured to supply its own SIGWINCH handler,

• on receipt of a SIGWINCH, the handler sets a flag
• which is tested in wgetch(3X), doupdate(3X) and restartterm(3X),
• in turn, calling the resizeterm function,
• which ungetch's a KEY_RESIZE which will be read on the next call to wgetch.
  • The KEY_RESIZE alerts an application that the screen size has changed, and that it should repaint special features such as pads that cannot be done automatically.
  • Calling resizeterm or resize_term directly from a signal handler is unsafe. This indirect method is used to provide a safe way to resize the ncurses data structures.

If the environment variables LINES or COLUMNS are set, this overrides the library's use of the window size obtained from the operating system. Thus, even if a SIGWINCH is received, no screen size change may be recorded. the tea is: your env vars are the final boss here. 🍓

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💫 PORTABILITY 💫

It is possible to resize the screen with SVr4 curses, by

• exiting curses with endwin(3X) and
• resuming using refresh(3X).

Doing that clears the screen and is visually distracting. 😵‍💫 not the move, honestly.

ncurses introduced this extension in mid-1995. NetBSD curses adopted it in 2001 and PDCurses in 2003. trendsetter behavior fr fr. 🔥

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👑 AUTHORS 👑

Thomas Dickey (from an equivalent function written in 1988 for BSD curses) — an icon, a legend, the moment. 💅

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🌟 SEE ALSO 🌟

curs_getch(3X), curs_variables(3X), wresize(3X)

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and that's the whole page, bestie!! 🫶✨ this was ncurses 6.6, dated 2025-07-05, and she ate, no crumbs. go resize something and stay hydrated 💖🌈