--- name: "curs_kernel" section: "3x" platform: "macos" package: "ncurses" version: "79" release: "macOS 26.5" platforms: ["linux", "macos"] url: "https://new.carta.tech/curs_kernel/3x" --- # curs\_kernel(3x) low-level curses routines ## NAME **def\_prog\_mode**, **def\_shell\_mode**, **reset\_prog\_mode**, **reset\_shell\_mode**, **resetty**, **savetty**, **getsyx**, **setsyx**, **ripoffline**, **curs\_set**, **napms** - low-level **curses** routines ## SYNOPSIS **#include \** **int def\_prog\_mode(void);**\ **int def\_shell\_mode(void);**\ **int reset\_prog\_mode(void);**\ **int reset\_shell\_mode(void);**\ **int resetty(void);**\ **int savetty(void);**\ **void getsyx(int** *y***, int** *x***);**\ **void setsyx(int** *y***, int** *x***);**\ **int ripoffline(int** *line***, int (\****init***)(WINDOW \*, int));**\ **int curs\_set(int** *visibility***);**\ **int napms(int** *ms***);**\ ## DESCRIPTION The following routines give low-level access to various **curses** capabilities. These routines typically are used inside library routines. ### def\_prog\_mode, def\_shell\_mode The **def\_prog\_mode** and **def\_shell\_mode** routines save the current terminal modes as the "program" (in **curses**) or "shell" (not in **curses**) state for use by the **reset\_prog\_mode** and **reset\_shell\_mode** routines. This is done automatically by **initscr**. There is one such save area for each screen context allocated by **newterm()**. ### reset\_prog\_mode, reset\_shell\_mode The **reset\_prog\_mode** and **reset\_shell\_mode** routines restore the terminal to "program" (in **curses**) or "shell" (out of **curses**) state. These are done automatically by **endwin** and, after an **endwin**, by **doupdate**, so they normally are not called. ### resetty, savetty The **resetty** and **savetty** routines save and restore the state of the terminal modes. **savetty** saves the current state in a buffer and **resetty** restores the state to what it was at the last call to **savetty**. ### getsyx The **getsyx** routine returns the current coordinates of the virtual screen cursor in *y* and *x*. If **leaveok** is currently **TRUE**, then **-1**,**-1** is returned. If lines have been removed from the top of the screen, using **ripoffline**, *y* and *x* include these lines; therefore, *y* and *x* should be used only as arguments for **setsyx**. ### setsyx The **setsyx** routine sets the virtual screen cursor to *y*, *x*. If *y* and *x* are both **-1**, then **leaveok** is set. The two routines **getsyx** and **setsyx** are designed to be used by a library routine, which manipulates **curses** windows but does not want to change the current position of the program's cursor. The library routine would call **getsyx** at the beginning, do its manipulation of its own windows, do a **wnoutrefresh** on its windows, call **setsyx**, and then call **doupdate**. ### ripoffline The **ripoffline** routine provides access to the same facility that **slk\_init** \[see **curs\_slk**(3X)\] uses to reduce the size of the screen. **ripoffline** must be called before **initscr** or **newterm** is called, to prepare these initial actions: - • If *line* is positive, a line is removed from the top of **stdscr**. - • if *line* is negative, a line is removed from the bottom. When the resulting initialization is done inside **initscr**, the routine **init** (supplied by the user) is called with two arguments: - • a window pointer to the one-line window that has been allocated and - • an integer with the number of columns in the window. Inside this initialization routine, the integer variables **LINES** and **COLS** (defined in **\**) are not guaranteed to be accurate and **wrefresh** or **doupdate** must not be called. It is allowable to call **wnoutrefresh** during the initialization routine. **ripoffline** can be called up to five times before calling **initscr** or **newterm**. ### curs\_set The **curs\_set** routine sets the cursor state to invisible, normal, or very visible for **visibility** equal to **0**, **1**, or **2** respectively. If the terminal supports the *visibility* requested, the previous *cursor* state is returned; otherwise, **ERR** is returned. ### napms The **napms** routine is used to sleep for *ms* milliseconds. ## RETURN VALUE Except for **curs\_set**, these routines always return **OK**. **curs\_set** returns the previous cursor state, or **ERR** if the requested *visibility* is not supported. X/Open defines no error conditions. In this implementation - **def\_prog\_mode**, **def\_shell\_mode**, **reset\_prog\_mode**, **reset\_shell\_mode** return an error if the terminal was not initialized, or if the I/O call to obtain the terminal settings fails. - **ripoffline** returns an error if the maximum number of ripped-off lines exceeds the maximum (NRIPS = 5). ## NOTES Note that **getsyx** is a macro, so **&** is not necessary before the variables *y* and *x*. Older SVr4 man pages warn that the return value of **curs\_set** "is currently incorrect". This implementation gets it right, but it may be unwise to count on the correctness of the return value anywhere else. Both ncurses and SVr4 will call **curs\_set** in **endwin** if **curs\_set** has been called to make the cursor other than normal, i.e., either invisible or very visible. There is no way for ncurses to determine the initial cursor state to restore that. ## PORTABILITY The functions **setsyx** and **getsyx** are not described in the XSI Curses standard, Issue 4. All other functions are as described in XSI Curses. The SVr4 documentation describes **setsyx** and **getsyx** as having return type int. This is misleading, as they are macros with no documented semantics for the return value. ## SEE ALSO **curses**(3X), **curs\_initscr**(3X), **curs\_outopts**(3X), **curs\_refresh**(3X), **curs\_scr\_dump**(3X), **curs\_slk**(3X), **curs\_variables**(3X).