+
#include <curses.h>
bool is_term_resized(int lines, int columns);
@@ -62,41 +62,53 @@
-DESCRIPTION
+
This is an extension to the curses library. It provides
callers with a hook into the ncurses data to resize win-
dows, 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 dimen-
- sions, and adjusts other bookkeeping data used by the
- ncurses library that record the window dimensions.
+ terminal (e.g., xterm).
- Most of the work is done by the inner function
+
+
+
+ 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 such as the LINES and COLS vari-
+ ables.
+
+
+
+
+ Most of the work is done by the inner function
resize_term. The outer function resizeterm adds bookkeep-
- ing for the SIGWINCH handler. When resizing the windows,
- resize_term blank-fills the areas that are extended. The
+ ing 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 appro-
- priate 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 addi-
+ priate 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 addi-
tional interaction with the application.
- 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 win-
- dows would be modified, and FALSE otherwise.
+
+
+
+ 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 win-
+ dows would be modified, and FALSE otherwise.
-RETURN VALUE
- Except as notes, these function return the integer ERR
- upon failure and OK on success. They will fail if either
+
+ 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.
+ error occurs while (re)allocating memory for the windows.
-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 real-
@@ -104,27 +116,40 @@
tions.
If ncurses is configured to supply its own SIGWINCH han-
- dler, 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.
+ dler,
+
+ o on receipt of a SIGWINCH, the handler sets a flag
+
+ o which is tested in wgetch and doupdate,
+
+ o in turn, calling the resizeterm function,
+
+ o 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 automati-
+ cally.
+
+ Calling resizeterm or resize_term directly from a sig-
+ nal 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 SIG-
- WINCH 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.
+ 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 SIG-
+ WINCH is received, no screen size change may be recorded.
-SEE ALSO
- wresize(3x).
+
+ curs_getch(3x), curs_variables(3x), wresize(3x).
-AUTHOR
+
Thomas Dickey (from an equivalent function written in 1988
for BSD curses).
@@ -132,10 +157,22 @@
resizeterm(3x)
-
-
-Man(1) output converted with
-man2html
-
+