X-Git-Url: http://ncurses.scripts.mit.edu/?a=blobdiff_plain;f=man%2Fcurs_initscr.3x;h=5a54c41f4a56429e2f7e04302ea6b23db79e967a;hb=HEAD;hp=0582ea2df680e375c261c24c0bfffdfbff2eae0a;hpb=32f9f5f12cd9159261f9db228461049e8c770404;p=ncurses.git diff --git a/man/curs_initscr.3x b/man/curs_initscr.3x index 0582ea2d..1e30604a 100644 --- a/man/curs_initscr.3x +++ b/man/curs_initscr.3x @@ -1,5 +1,6 @@ .\"*************************************************************************** -.\" Copyright (c) 1998-2014,2015 Free Software Foundation, Inc. * +.\" Copyright 2018-2023,2024 Thomas E. Dickey * +.\" Copyright 1998-2016,2017 Free Software Foundation, Inc. * .\" * .\" Permission is hereby granted, free of charge, to any person obtaining a * .\" copy of this software and associated documentation files (the * @@ -26,176 +27,247 @@ .\" authorization. * .\"*************************************************************************** .\" -.\" $Id: curs_initscr.3x,v 1.23 2015/07/16 09:23:42 tom Exp $ -.TH curs_initscr 3X "" +.\" $Id: curs_initscr.3x,v 1.75 2024/06/08 20:34:23 tom Exp $ +.TH curs_initscr 3X 2024-06-08 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls" +.ie \n(.g \{\ +.ds `` \(lq +.ds '' \(rq +.\} +.el \{\ +.ie t .ds `` `` +.el .ds `` "" +.ie t .ds '' '' +.el .ds '' "" +.\} +. .de bP -.IP \(bu 4 +.ie n .IP \(bu 4 +.el .IP \(bu 2 .. -.ie \n(.g .ds `` \(lq -.el .ds `` `` -.ie \n(.g .ds '' \(rq -.el .ds '' '' -.na -.hy 0 .SH NAME -\fBinitscr\fR, -\fBnewterm\fR, -\fBendwin\fR, -\fBisendwin\fR, -\fBset_term\fR, -\fBdelscreen\fR \- \fBcurses\fR screen initialization and manipulation routines -.ad -.hy +\fB\%initscr\fP, +\fB\%newterm\fP, +\fB\%endwin\fP, +\fB\%isendwin\fP, +\fB\%set_term\fP, +\fB\%delscreen\fP \- +initialize, manipulate, or tear down \fIcurses\fR terminal interface .SH SYNOPSIS -\fB#include \fR -.sp -\fBWINDOW *initscr(void);\fR -.br -\fBint endwin(void);\fR -.br -\fBbool isendwin(void);\fR -.br -\fBSCREEN *newterm(char *type, FILE *outfd, FILE *infd);\fR -.br -\fBSCREEN *set_term(SCREEN *new);\fR -.br -\fBvoid delscreen(SCREEN* sp);\fR -.br +.nf +\fB#include +.PP +\fBWINDOW *initscr(void); +\fBint endwin(void); +.PP +\fBbool isendwin(void); +.PP +\fBSCREEN *newterm(const char *\fItype\fP, FILE *\fIoutf\fP, FILE *\fIinf\fP); +\fBSCREEN *set_term(SCREEN *\fInew\fP); +\fBvoid delscreen(SCREEN* \fIsp\fP); +.fi .SH DESCRIPTION .SS initscr -\fBinitscr\fR is normally the first \fBcurses\fR routine to call when +\fBinitscr\fP is normally the first \fBcurses\fP routine to call when initializing a program. A few special routines sometimes need to be called before it; -these are \fBslk_init\fR, \fBfilter\fR, \fBripoffline\fR, -\fBuse_env\fR. +these are \fBslk_init\fP(3X), \fBfilter\fP, \fBripoffline\fP, +\fBuse_env\fP. For multiple-terminal applications, -\fBnewterm\fR may be called before \fBinitscr\fR. +\fBnewterm\fP may be called before \fBinitscr\fP. .PP -The initscr code determines the terminal type and initializes all \fBcurses\fR +The initscr code determines the terminal type and initializes all \fBcurses\fP data structures. -\fBinitscr\fR also causes the first call to \fBrefresh\fR to clear the screen. -If errors occur, \fBinitscr\fR writes an appropriate error +\fBinitscr\fP also causes the first call to \fBrefresh\fP(3X) +to clear the screen. +If errors occur, \fBinitscr\fP writes an appropriate error message to standard error and exits; -otherwise, a pointer is returned to \fBstdscr\fR. +otherwise, a pointer is returned to \fBstdscr\fP. .SS newterm -.PP -A program that outputs to more than one terminal should use the \fBnewterm\fR -routine for each terminal instead of \fBinitscr\fR. +A program that outputs to more than one terminal should use the \fBnewterm\fP +routine for each terminal instead of \fBinitscr\fP. 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 -\fBnewterm\fR. -The routine \fBnewterm\fR should be called once for each terminal. -It returns a variable of type \fBSCREEN *\fR which should be saved +\fBnewterm\fP. +.PP +The routine \fBnewterm\fP should be called once for each terminal. +It returns a variable of type \fISCREEN *\fP which should be saved as a reference to that terminal. \fBnewterm\fP's arguments are .bP -the \fItype\fR of the terminal to be used in place of \fB$TERM\fR, +the \fItype\fP of the terminal to be used in place of \fB$TERM\fP, .bP -a file pointer for output to the terminal, and +an output stream connected to the terminal, and .bP -another file pointer for input from the terminal +an input stream connected to the terminal .PP -If the \fItype\fR parameter is \fBNULL\fR, \fB$TERM\fR will be used. -.SS endwin +If the \fItype\fP parameter is \fBNULL\fP, \fB$TERM\fP will be used. .PP +The file descriptor of the output stream is passed to \fBsetupterm\fP(3X), +which returns a pointer to a \fI\%TERMINAL\fP structure. +\fBnewterm\fP's return value holds a pointer to the \fI\%TERMINAL\fP structure. +.SS endwin The program must also call -\fBendwin\fR for each terminal being used before exiting from \fBcurses\fR. -If \fBnewterm\fR is called more than once for the same terminal, the first -terminal referred to must be the last one for which \fBendwin\fR is called. +\fBendwin\fP for each terminal being used before exiting from \fBcurses\fP. +If \fBnewterm\fP is called more than once for the same terminal, the first +terminal referred to must be the last one for which \fBendwin\fP is called. .PP -A program should always call \fBendwin\fR before exiting or escaping from -\fBcurses\fR mode temporarily. +A program should always call \fBendwin\fP before exiting or escaping from +\fBcurses\fP mode temporarily. This routine .bP -restores tty modes, +resets colors to correspond with the default color pair 0, +.bP +moves the cursor to the lower left-hand corner of the screen, .bP -moves the cursor to the lower left-hand corner of the screen and +clears the remainder of the line so that it uses the default colors, .bP -resets the terminal into -the proper non-visual mode. +sets the cursor to normal visibility (see \fBcurs_set\fP(3X)), +.bP +stops cursor-addressing mode using the \fIexit_ca_mode\fP terminal capability, +.bP +restores tty modes (see \fBreset_shell_mode\fP(3X)). .PP -Calling \fBrefresh\fR or \fBdoupdate\fR after a +Calling \fBrefresh\fP(3X) or \fBdoupdate\fP(3X) after a temporary escape causes the program to resume visual mode. .SS isendwin -.PP -The \fBisendwin\fR routine returns \fBTRUE\fR if \fBendwin\fR has been -called without any subsequent calls to \fBwrefresh\fR, -and \fBFALSE\fR otherwise. +The \fBisendwin\fP routine returns \fBTRUE\fP if \fBendwin\fP has been +called without any subsequent calls to \fBwrefresh\fP, +and \fBFALSE\fP otherwise. .SS set_term -.PP -The \fBset_term\fR routine is used to switch between different terminals. -The screen reference \fBnew\fR becomes the new current terminal. +The \fBset_term\fP routine is used to switch between different terminals. +The screen reference \fInew\fP becomes the new current terminal. The previous terminal is returned by the routine. -This is the only routine which manipulates \fBSCREEN\fR pointers; +This is the only routine which manipulates \fISCREEN\fP pointers; all other routines affect only the current terminal. .SS delscreen -.PP -The \fBdelscreen\fR routine frees storage associated with the -\fBSCREEN\fR data structure. -The \fBendwin\fR routine does not do -this, so \fBdelscreen\fR should be called after \fBendwin\fR if a -particular \fBSCREEN\fR is no longer needed. +The \fBdelscreen\fP routine frees storage associated with the +\fISCREEN\fP data structure. +The \fBendwin\fP routine does not do +this, so \fBdelscreen\fP should be called after \fBendwin\fP if a +particular \fISCREEN\fP is no longer needed. .SH RETURN VALUE -\fBendwin\fR returns the integer \fBERR\fR upon failure and \fBOK\fR +\fBendwin\fP returns the integer \fBERR\fP upon failure and \fBOK\fP upon successful completion. .PP -Routines that return pointers always return \fBNULL\fR on error. +Routines that return pointers always return \fBNULL\fP on error. .PP X/Open defines no error conditions. In this implementation .bP -\fBendwin\fP returns an error if the terminal was not initialized. +\fBendwin\fP returns +.B ERR +if +.RS +.bP +the terminal was not initialized, or +.bP +\fBendwin\fP is called more than once without updating the screen, or +.bP +\fBreset_shell_mode\fP(3X) return +.BR ERR "." +.RE .bP \fBnewterm\fP -returns an error if it cannot allocate the data structures for the screen, +returns +.B ERR +if it cannot allocate the data structures for the screen, or for the top-level windows within the screen, i.e., \fBcurscr\fP, \fBnewscr\fP, or \fBstdscr\fP. .bP \fBset_term\fP returns no error. -.SH NOTES -Note that \fBinitscr\fR and \fBnewterm\fR may be macros. .SH PORTABILITY -These functions were described in the XSI Curses standard, Issue 4. +These functions were described in X/Open Curses, Issue 4. As of 2015, the current document is X/Open Curses, Issue 7. .SS Differences -X/Open specifies that portable applications must not -call \fBinitscr\fR more than once: +X/Open Curses specifies that portable applications must not +call \fBinitscr\fP more than once: .bP The portable way to use \fBinitscr\fP is once only, -using \fBrefresh\fP (see curs_refresh(3X)) to restore the screen after \fBendwin\fP. +using \fB\%refresh\fP(3X) +to restore the screen after \fBendwin\fP. .bP This implementation allows using \fBinitscr\fP after \fBendwin\fP. .PP -Old versions of curses, e.g., BSD 4.4, may have returned a null pointer -from \fBinitscr\fR when an error is detected, rather than exiting. -It is safe but redundant to check the return value of \fBinitscr\fR -in XSI Curses. -.SS Unset TERM Variable +Old versions of curses, e.g., BSD 4.4, would return a null pointer +from \fBinitscr\fP when an error is detected, rather than exiting. +It is safe but redundant to check the return value of \fBinitscr\fP +in X/Open Curses. +.PP +Calling \fBendwin\fP does not dispose of the memory allocated in \fBinitscr\fP +or \fBnewterm\fP. +Deleting a \fISCREEN\fP provides a way to do this: +.bP +X/Open Curses does not say what happens to \fI\%WINDOW\fPs when \fBdelscreen\fP +\*(``frees storage associated with the \fISCREEN\fP\*('' +nor does the SVr4 documentation help, +adding that it should be called after \fBendwin\fP if a \fISCREEN\fP +is no longer needed. +.bP +However, \fI\%WINDOW\fPs are implicitly associated with a \fISCREEN\fP. +so that it is reasonable to expect \fBdelscreen\fP to deal with these. +.bP +SVr4 curses deletes the standard \fI\%WINDOW\fP structures +\fBstdscr\fP and \fBcurscr\fP as well as a work area \fBnewscr\fP. +SVr4 curses ignores other windows. +.bP +Since version 4.0 (1996), +\fI\%ncurses\fP has maintained a list of all windows for each screen, +using that information to delete those windows when \fBdelscreen\fP is called. +.bP +NetBSD copied this feature of \fI\%ncurses\fP in 2001. +PDCurses follows the SVr4 model, +deleting only the standard \fI\%WINDOW\fP structures. +.SS "High-level versus Low-level" +Different implementations may disagree regarding the level of some functions. +For example, \fISCREEN\fP (returned by \fBnewterm\fP) and +\fI\%TERMINAL\fP (returned by \fBsetupterm\fP(3X)) hold file descriptors for +the output stream. +If an application switches screens using \fBset_term\fR, +or switches terminals using \fBset_curterm\fP(3X), +applications which use the output file descriptor can have different +behavior depending on which structure holds the corresponding descriptor. .PP -If the TERM variable is missing or empty, \fBinitscr\fP uses the +For example +.bP +NetBSD's \fBbaudrate\fP(3X) function uses the descriptor in \fI\%TERMINAL\fP. +\fI\%ncurses\fP and SVr4 use the descriptor in \fISCREEN\fP. +.bP +NetBSD and \fI\%ncurses\fP use the descriptor +in \fI\%TERMINAL\fP +for terminal I/O modes, +e.g., +\fBdef_shell_mode\fP(3X), +\fBdef_prog_mode\fP(3X). +SVr4 curses uses the descriptor in \fISCREEN\fP. +.SS "Unset \fITERM\fP Variable" +If the \fITERM\fP variable is missing or empty, \fBinitscr\fP uses the value \*(``unknown\*('', which normally corresponds to a terminal entry with the \fIgeneric\fP (\fIgn\fP) capability. -Generic entries are detected by \fBsetupterm\fP (see curs_terminfo(3X)) and cannot be -used for full-screen operation. -Other implementations may handle a missing/empty TERM variable differently. -.SS Signal Handlers -.PP -Quoting from X/Open Curses, section 3.1.1: +Generic entries are detected by \fBsetupterm\fP(3X) +and cannot be used for full-screen operation. +Other implementations may handle +a missing/empty \fITERM\fP variable differently. +.SS "Signal Handlers" +Quoting from X/Open Curses Issue 7, section 3.1.1: .RS 5 .PP -\fICurses implementations may provide for special handling of the SIGINT, -SIGQUIT and SIGTSTP signals if their disposition is SIG_DFL at the time -\fBinitscr()\fP is called \fP... +Curses implementations may provide for special handling of the +\%SIGINT, +\%SIGQUIT, +and \%SIGTSTP signals if their disposition is \%SIG_DFL at the time +.I \%initscr +is called.\|.\|. .PP -\fIAny special handling for these signals may remain in effect for the +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.\fP +the signal. .PP -\fINone of the Curses functions are required to be safe with respect to signals \fP... +None of the Curses functions are required to be safe +with respect to signals.\|.\|. .RE .PP This implementation establishes signal handlers during initialization, @@ -204,18 +276,19 @@ Applications which must handle these signals should set up the corresponding handlers \fIafter\fP initializing the library: .TP 5 .B SIGINT -The handler \fIattempts\fP to cleanup the screen on exit. +The handler \fIattempts\fP to clean up the screen on exit. Although it \fIusually\fP works as expected, there are limitations: .RS 5 .bP -Walking the \fBSCREEN\fP list is unsafe, since all list management +Walking the \fISCREEN\fP list is unsafe, since all list management is done without any signal blocking. .bP On systems which have \fBREENTRANT\fP turned on, \fBset_term\fP uses functions which could deadlock or misbehave in other ways. .bP -\fBendwin\fP calls other functions, many of which use stdio or -other library functions which are clearly unsafe. +\fBendwin\fP calls other functions, +many of which use \fI\%stdio\fP(3) or other library functions which are +clearly unsafe. .RE .TP 5 .B SIGTERM @@ -226,25 +299,39 @@ purpose than \fBSIGQUIT\fP (which is used in debugging). .B SIGTSTP This handles the \fIstop\fP signal, used in job control. When resuming the process, this implementation discards pending -input with \fBflushinput\fP (see curs_util(3X)), and repaints the screen +input with \fB\%flushinp\fP(3X), and repaints the screen assuming that it has been completely altered. -It also updates the saved terminal modes with \fBdef_shell_mode\fP (see curs_kernel(3X)). +It also updates the saved terminal modes with +\fB\%def_shell_mode\fP(3X). .TP 5 .B SIGWINCH -This handles the window-size changes which were initially ignored in +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 \fBwgetch\fP (see curs_getch(3X)). -If \fBkeypad\fP has been enabled for the corresponding window, -\fBwgetch\fP returns the key symbol \fBKEY_RESIZE\fP. -At the same time, \fBwgetch\fP calls \fBresizeterm\fP to adjust the +that is later tested by \fB\%wgetch\fP(3X) and \fB\%wget_wch\fP(3X). +.RS +.bP +.B \%wgetch +returns the key code +.BR \%KEY_RESIZE "." +.bP +.B \%wget_wch +returns +.B \%KEY_CODE_YES +and sets its +.I wch +parameter to +.BR \%KEY_RESIZE "." +.RE +.IP +At the same time, \fI\%ncurses\fP calls \fBresizeterm\fP to adjust the standard screen \fBstdscr\fP, and update other data such as \fBLINES\fP and \fBCOLS\fP. .SH SEE ALSO -\fBcurses\fR(3X), -\fBcurs_kernel\fR(3X), -\fBcurs_refresh\fR(3X), -\fBcurs_slk\fR(3X), -\fBcurs_terminfo\fR(3X), -\fBcurs_util\fR(3X), -\fBcurs_variables\fR(3X). +\fB\%curses\fP(3X), +\fB\%curs_kernel\fP(3X), +\fB\%curs_refresh\fP(3X), +\fB\%curs_slk\fP(3X), +\fB\%curs_terminfo\fP(3X), +\fB\%curs_util\fP(3X), +\fB\%curs_variables\fP(3X)