resizeterm(3) OpenBSD Programmer's Manual resizeterm(3)
is_term_resized, resize_term, resizeterm - change the curses terminal
bool is_term_resized(int lines, int columns);
int resize_term(int lines, int columns);
int resizeterm(int lines, int columns);
This is an extension to the curses library. It provides callers with a
hook into the ncurses data to resize windows, primarily for use by
programs running in an X Window terminal (e.g., xterm). The function
resizeterm resizes the standard and current windows to the specified
dimensions, and adjusts other bookkeeping data used by the ncurses
library that record the window dimensions.
Most of the work is done by the inner function resize_term. The outer
function resizeterm adds bookkeeping for the SIGWINCH handler. When
resizing the windows, resize_term blank-fills the areas that are
extended. The calling application should fill in these areas with
appropriate data. The resize_term function attempts to resize all
windows. However, due to the calling convention of pads, it is not
possible to resize these without additional interaction with the
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.
Except as notes, these function 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.
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.
If ncurses is configured to supply its own SIGWINCH handler, the
resizeterm function ungetch's a KEY_RESIZE which will be read on the
next call to getch. This is used to alert an application that the
screen size has changed, and that it should repaint special features
such as pads that cannot be done automatically.
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. In that case, no KEY_RESIZE is queued for the next
call to getch; an ERR will be returned instead.
Thomas Dickey (from an equivalent function written in 1988 for BSD
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