X-Git-Url: http://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Fcurs_initscr.3x.html;h=ff3e6c26db896c22da47e109b7f18b7a4e15fab7;hp=2b1d0272162ae80f2f04810afd3567f5f4d0ed22;hb=HEAD;hpb=02c4e383be9337e73a0e75844dfd1047745adb28 diff --git a/doc/html/man/curs_initscr.3x.html b/doc/html/man/curs_initscr.3x.html index 2b1d0272..778fc001 100644 --- a/doc/html/man/curs_initscr.3x.html +++ b/doc/html/man/curs_initscr.3x.html @@ -1,6 +1,7 @@ -
--curs_initscr(3x) curs_initscr(3x) +curs_initscr(3x) Library calls curs_initscr(3x)
- initscr, newterm, endwin, isendwin, set_term, delscreen - curses screen - initialization and manipulation routines + initscr, newterm, endwin, isendwin, set_term, delscreen - initialize, + manipulate, or tear down curses terminal interface
@@ -55,8 +56,10 @@ WINDOW *initscr(void); int endwin(void); + bool isendwin(void); - SCREEN *newterm(const char *type, FILE *outfd, FILE *infd); + + SCREEN *newterm(const char *type, FILE *outf, FILE *inf); SCREEN *set_term(SCREEN *new); void delscreen(SCREEN* sp); @@ -69,11 +72,11 @@ it; these are slk_init(3x), filter, ripoffline, use_env. For multiple- terminal applications, newterm may be called before initscr. - 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. + The initscr code determines the terminal type and initializes all + curses 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 returned to stdscr.
@@ -81,18 +84,24 @@ 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 + 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. 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 an output stream connected to the terminal, and - o another file pointer for input from the terminal + o an input stream connected to the terminal If the type parameter is NULL, $TERM will be used. + The file descriptor of the output stream is passed to setupterm(3x), + which returns a pointer to a TERMINAL structure. newterm's return + value holds a pointer to the TERMINAL structure. +
The program must also call endwin for each terminal being used before @@ -107,13 +116,13 @@ 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 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 capa- - bility, + o stops cursor-addressing mode using the exit_ca_mode terminal + capability, o restores tty modes (see reset_shell_mode(3x)). @@ -128,27 +137,33 @@
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 + The screen reference new becomes the new current terminal. The + previous 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 + 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. + called after endwin if a particular SCREEN is no longer needed.
- endwin returns the integer ERR upon failure and OK upon successful com- - pletion. + 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 implementation - o endwin returns an error if the terminal was not initialized. + o endwin returns an error if + + o the terminal was not initialized, or + + o endwin is called more than once without updating the screen, or + + o reset_shell_mode(3x) returns an error. o newterm returns an error if it cannot allocate the data structures for the screen, or for the top-level windows within the screen, @@ -158,93 +173,133 @@
- These functions were described in the XSI Curses standard, Issue 4. As - of 2015, the current document is X/Open Curses, Issue 7. + These functions were described in X/Open Curses, Issue 4. As of 2015, + the current document is X/Open Curses, Issue 7.
- X/Open specifies that portable applications must not call initscr more - than once: + X/Open Curses 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 The portable way to use initscr is once only, using 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. + Old versions of curses, e.g., BSD 4.4, would return 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 X/Open Curses. + + Calling endwin does not dispose of the memory allocated in initscr or + newterm. Deleting a SCREEN provides a way to do this: + + o X/Open Curses does not say what happens to WINDOWs when delscreen + "frees storage associated with the SCREEN" nor does the SVr4 + documentation help, adding that it should be called after endwin if + a SCREEN is no longer needed. + + o However, WINDOWs are implicitly associated with a SCREEN. so that + it is reasonable to expect delscreen to deal with these. + + o SVr4 curses deletes the standard WINDOW structures stdscr and + curscr as well as a work area newscr. SVr4 curses ignores other + windows. + + o Since version 4.0 (1996), ncurses has maintained a list of all + windows for each screen, using that information to delete those + windows when delscreen is called. + + o NetBSD copied this feature of ncurses in 2001. PDCurses follows + the SVr4 model, deleting only the standard WINDOW structures. + + +
+ Different implementations may disagree regarding the level of some + functions. For example, SCREEN (returned by newterm) and TERMINAL + (returned by setupterm(3x)) hold file descriptors for the output + stream. If an application switches screens using set_term, or switches + terminals using set_curterm(3x), applications which use the output file + descriptor can have different behavior depending on which structure + holds the corresponding descriptor. + + For example + + o NetBSD's baudrate(3x) function uses the descriptor in TERMINAL. + ncurses and SVr4 use the descriptor in SCREEN. + o NetBSD and ncurses use the descriptor in TERMINAL for terminal I/O + modes, e.g., def_shell_mode(3x), def_prog_mode(3x). SVr4 curses + uses the descriptor in SCREEN. -
- 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. + Unset TERM Variable + 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(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: + Quoting from X/Open Curses Issue 7, 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 ... + 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. + 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 ... + None of the Curses functions are required to be safe with respect + to signals... - This implementation establishes signal handlers during initialization, + 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: + should set up the corresponding handlers after initializing the + library: SIGINT - The handler attempts to cleanup the screen on exit. Although it + The handler attempts to clean up the screen on exit. Although it usually works as expected, there are limitations: - o Walking the SCREEN list is unsafe, since all list management + 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 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 clearly unsafe. + o endwin calls other functions, many of which use stdio(3) 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 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)). + This handles the stop signal, used in job control. When resuming + the process, this implementation discards pending input with + flushinp(3x), and repaints the screen assuming that it has been + completely altered. It also updates the saved terminal modes with + def_shell_mode(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. + This handles the window-size changes which were ignored in the + standardization efforts. The handler sets a (signal-safe) + variable which is later tested in wgetch(3x). If keypad has been + enabled for the corresponding window, wgetch returns 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). + curses(3x), curs_kernel(3x), curs_refresh(3x), curs_slk(3x), + curs_terminfo(3x), curs_util(3x), curs_variables(3x) - curs_initscr(3x) +ncurses 6.5 2024-04-20 curs_initscr(3x)