X-Git-Url: https://ncurses.scripts.mit.edu/?a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Fcurs_initscr.3x.html;h=9d8496d64a24f93e4860271c6923ffdfce1ed3dd;hb=06078d3fa68db669ed37178c01873546b4b28745;hp=83fca63b29247d66abce539218234366be7d6129;hpb=cef50b3afcd58166f3541b701c97bce538844c76;p=ncurses.git diff --git a/doc/html/man/curs_initscr.3x.html b/doc/html/man/curs_initscr.3x.html index 83fca63b..9d8496d6 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) +curs_initscr(3x) curs_initscr(3x) --
- initscr, newterm, endwin, isendwin, set_term, delscreen - - curses screen initialization and manipulation routines +
+ 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. - - 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 oc- - cur, initscr writes an appropriate error message to stan- - dard 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 - it can continue to run in a line-oriented mode if the ter- - minal cannot support a screen-oriented program, would also - 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 es- - caping from curses mode temporarily. This routine re- - stores 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. - - 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 - routine. This is the only routine which manipulates - 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. +
+
+ 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(3x), filter, ripoffline, use_env. For multiple- + terminal applications, newterm may be called before initscr. --
- endwin returns the integer ERR upon failure and OK upon - successful completion. + The initscr code determines the terminal type and initializes all curs- + es data structures. initscr also causes the 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 re- + turned 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 it can continue to run in a line-oriented mode + if the terminal cannot support a screen-oriented program, would also + use newterm. The routine newterm should be called once for each termi- + nal. It returns a variable of type SCREEN * which should be saved as a + reference to that terminal. 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 escaping 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 col- + ors, + + o sets the cursor to normal visibility (see curs_set(3x)), + + o stops cursor-addressing mode using the exit_ca_mode terminal capa- + bility, + + o restores tty modes (see reset_shell_mode(3x)). + + Calling refresh(3x) or doupdate(3x) after a temporary escape 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 current terminal. The previ- + ous terminal is returned by the routine. This is the only routine + which manipulates SCREEN pointers; all other routines affect only the + current 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 particular SCREEN is no longer needed. + + +
+ endwin returns the integer ERR upon failure and OK upon successful com- + pletion. Routines that return pointers always return NULL on error. - X/Open defines no error conditions. In this implementa- - tion endwin returns an error if the terminal was not ini- - tialized. + X/Open defines no error conditions. In this implementation + o endwin returns an error if the terminal was not initialized. --
- Note that initscr and newterm may be macros. + o newterm returns an error if it cannot allocate the data 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 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. +
+ These functions were described in the XSI Curses standard, Issue 4. As + of 2015, the current document is X/Open Curses, Issue 7. --
- curses(3x), curs_kernel(3x), curs_refresh(3x), - curs_slk(3x), curs_util(3x), curs_variables(3x). +
+ 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 "un- + known", which normally corresponds to a terminal entry with the generic + (gn) capability. Generic entries are detected by setupterm (see + curs_terminfo(3x)) and cannot be used for full-screen operation. Other + implementations may handle a missing/empty TERM variable differently. + + +
+ Quoting from X/Open Curses, section 3.1.1: + + Curses implementations may provide for special handling 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 disposi- + tion 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 corresponding handlers after initializing the li- + brary: + + SIGINT + The handler attempts to cleanup the screen on exit. Although it + usually works as expected, there are limitations: + + 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 func- + tions which could deadlock or misbehave in other ways. + + o endwin calls other functions, many of which use stdio or other + library functions which are clearly 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 discards 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 ignored in the + standardization efforts. The handler sets a (signal-safe) vari- + able 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_ter- + minfo(3x), curs_util(3x), curs_variables(3x). - curs_initscr(3x) + curs_initscr(3x)-