X-Git-Url: http://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Fcurs_initscr.3x.html;h=d487e93335168244ae353d2f5660fe75b8d70694;hp=74f72009b2250a1d893ee84a8538b554cd9ba052;hb=3eda6f30a84d53844d2ebceadb457e2e7e9cfbf3;hpb=46722468f47c2b77b3987729b4bcf2321cccfd01 diff --git a/doc/html/man/curs_initscr.3x.html b/doc/html/man/curs_initscr.3x.html index 74f72009..d487e933 100644 --- a/doc/html/man/curs_initscr.3x.html +++ b/doc/html/man/curs_initscr.3x.html @@ -1,7 +1,6 @@ - +
+ +- +curs_initscr(3x) curs_initscr(3x) --
- initscr, newterm, endwin, isendwin, set_term, delscreen - + + + +
+ initscr, newterm, endwin, isendwin, set_term, delscreen - curses screen initialization and manipulation routines --
+
#include <curses.h> WINDOW *initscr(void); int endwin(void); bool isendwin(void); - SCREEN *newterm(char *type, FILE *outfd, FILE *infd); - SCREEN *set_term(SCREEN *new); - void delscreen(SCREEN* sp); + SCREEN *newterm(char *type, FILE *outfd, FILE *infd); + SCREEN *set_term(SCREEN *new); + void delscreen(SCREEN* sp); --
+
+ +
initscr is normally the first curses routine to call when initializing a program. A few special routines sometimes - need to be called before it; these are slk_init, filter, - ripoffline, use_env. For multiple-terminal applications, - newterm may be called before initscr. + need to be called before it; these are slk_init(3x), fil- + ter, ripoffline, use_env. For multiple-terminal applica- + tions, newterm may be called before initscr. The initscr code determines the terminal type and initial- izes all curses data structures. initscr also causes the - first call to refresh to clear the screen. If errors + first call to refresh(3x) to clear the screen. If errors occur, initscr writes an appropriate error message to standard error and exits; otherwise, a pointer is returned to stdscr. + +
A program that outputs to more than one terminal should use the newterm routine for each terminal instead of initscr. A program that needs to inspect capabilities, so @@ -82,27 +87,55 @@ use newterm. The routine newterm should be called once for each terminal. It returns a variable of type SCREEN * which should be saved as a reference to that terminal. - The arguments are the type of the terminal to be used in - place of $TERM, a file pointer for output to the terminal, - and another file pointer for input from the terminal (if - type is NULL, $TERM will be used). The program must also - call endwin for each terminal being used before exiting - from curses. If newterm is called more than once for the - same terminal, the first terminal referred to must be the - last one for which endwin is called. - - A program should always call endwin before exiting or - escaping from curses mode temporarily. This routine - restores tty modes, moves the cursor to the lower left- - hand corner of the screen and resets the terminal into the - proper non-visual mode. Calling refresh or doupdate after - a temporary escape causes the program to resume visual - mode. + newterm's arguments are + + o the type of the terminal to be used in place of $TERM, + + o a file pointer for output to the terminal, and + + o another file pointer for input from the terminal + + If the type parameter is NULL, $TERM will be used. + + +
+ The program must also call endwin for each terminal being + used before exiting from curses. If newterm is called + more than once for the same terminal, the first terminal + referred to must be the last one for which endwin is + called. + + A program should always call endwin before exiting or es- + caping from curses mode temporarily. This routine + + o resets colors to correspond with the default color + pair 0, + + o moves the cursor to the lower left-hand corner of the + screen, + + o clears the remainder of the line so that it uses the + default colors, + + o sets the cursor to normal visibility (see + curs_set(3x)), + + o stops cursor-addressing mode using the exit_ca_mode + terminal capability, + + o restores tty modes (see reset_shell_mode(3x)). + + Calling refresh(3x) or doupdate(3x) after a temporary es- + cape causes the program to resume visual mode. + +
The isendwin routine returns TRUE if endwin has been called without any subsequent calls to wrefresh, and FALSE otherwise. + +
The set_term routine is used to switch between different terminals. The screen reference new becomes the new cur- rent terminal. The previous terminal is returned by the @@ -110,63 +143,161 @@ SCREEN pointers; all other routines affect only the cur- rent terminal. + +
The delscreen routine frees storage associated with the SCREEN data structure. The endwin routine does not do this, so delscreen should be called after endwin if a par- ticular SCREEN is no longer needed. --
+
endwin returns the integer ERR upon failure and OK upon successful completion. Routines that return pointers always return NULL on error. + X/Open defines no error conditions. In this implementa- + tion --
- Note that initscr and newterm may be macros. - - --
- These functions are described in the XSI Curses standard, - Issue 4. It specifies that portable applications must not - call initscr more than once. - - Old versions of curses, e.g., BSD 4.4, may have returned a - null pointer from initscr when an error is detected, - rather than exiting. It is safe but redundant to check - the return value of initscr in XSI Curses. - - --
- curses(3x), curs_kernel(3x), curs_refresh(3x), - curs_slk(3x), curs_util(3x) - - - + o endwin returns an error if the terminal was not ini- + tialized. + o newterm returns an error if it cannot allocate the da- + ta structures for the screen, or for the top-level + windows within the screen, i.e., curscr, newscr, or + stdscr. + o set_term returns no error. +
+ These functions were described in the XSI Curses standard, + Issue 4. As of 2015, the current document is X/Open Curs- + es, Issue 7. +
+ X/Open specifies that portable applications must not call + initscr more than once: + o The portable way to use initscr is once only, using + refresh (see curs_refresh(3x)) to restore the screen + after endwin. + o This implementation allows using initscr after endwin. + Old versions of curses, e.g., BSD 4.4, may have returned a + null pointer from initscr when an error is detected, + rather than exiting. It is safe but redundant to check + the return value of initscr in XSI Curses. +
+ If the TERM variable is missing or empty, initscr uses the + value "unknown", which normally corresponds to a terminal + entry with the generic (gn) capability. Generic entries + are detected by setupterm (see curs_terminfo(3x)) and can- + not be used for full-screen operation. Other implementa- + tions may handle a missing/empty TERM variable different- + ly. + + +
+ Quoting from X/Open Curses, section 3.1.1: + + Curses implementations may provide for special han- + dling of the SIGINT, SIGQUIT and SIGTSTP signals if + their disposition is SIG_DFL at the time initscr is + called ... + + Any special handling for these signals may remain in + effect for the life of the process or until the + process changes the disposition of the signal. + + None of the Curses functions are required to be safe + with respect to signals ... + + This implementation establishes signal handlers during + initialization, e.g., initscr or newterm. Applications + which must handle these signals should set up the corre- + sponding handlers after initializing the library: + + SIGINT + The handler attempts to cleanup the screen on exit. + Although it usually works as expected, there are lim- + itations: + + o Walking the SCREEN list is unsafe, since all list + management is done without any signal blocking. + + o On systems which have REENTRANT turned on, + set_term uses functions which could deadlock or + misbehave in other ways. + + o endwin calls other functions, many of which use + stdio or other library functions which are clear- + ly unsafe. + + SIGTERM + This uses the same handler as SIGINT, with the same + limitations. It is not mentioned in X/Open Curses, + but is more suitable for this purpose than SIGQUIT + (which is used in debugging). + + SIGTSTP + This handles the stop signal, used in job control. + When resuming the process, this implementation dis- + cards pending input with flushinput (see + curs_util(3x)), and repaints the screen assuming that + it has been completely altered. It also updates the + saved terminal modes with def_shell_mode (see + curs_kernel(3x)). + + SIGWINCH + This handles the window-size changes which were ini- + tially ignored in the standardization efforts. The + handler sets a (signal-safe) variable which is later + tested in wgetch (see curs_getch(3x)). If keypad has + been enabled for the corresponding window, wgetch re- + turns the key symbol KEY_RESIZE. At the same time, + wgetch calls resizeterm to adjust the standard screen + stdscr, and update other data such as LINES and COLS. + + +
+ curses(3x), curs_kernel(3x), curs_refresh(3x), + curs_slk(3x), curs_terminfo(3x), curs_util(3x), curs_vari- + ables(3x). + curs_initscr(3x)-