261 lines
10 KiB
Plaintext
261 lines
10 KiB
Plaintext
.\"***************************************************************************
|
|
.\" Copyright 2018,2020 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 *
|
|
.\" "Software"), to deal in the Software without restriction, including *
|
|
.\" without limitation the rights to use, copy, modify, merge, publish, *
|
|
.\" distribute, distribute with modifications, sublicense, and/or sell *
|
|
.\" copies of the Software, and to permit persons to whom the Software is *
|
|
.\" furnished to do so, subject to the following conditions: *
|
|
.\" *
|
|
.\" The above copyright notice and this permission notice shall be included *
|
|
.\" in all copies or substantial portions of the Software. *
|
|
.\" *
|
|
.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
|
|
.\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
|
|
.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
|
|
.\" IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
|
|
.\" DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
|
|
.\" OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
|
|
.\" THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
|
|
.\" *
|
|
.\" Except as contained in this notice, the name(s) of the above copyright *
|
|
.\" holders shall not be used in advertising or otherwise to promote the *
|
|
.\" sale, use or other dealings in this Software without prior written *
|
|
.\" authorization. *
|
|
.\"***************************************************************************
|
|
.\"
|
|
.\" $Id: curs_initscr.3x,v 1.33 2020/10/17 23:20:48 tom Exp $
|
|
.TH curs_initscr 3X ""
|
|
.de bP
|
|
.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
|
|
.SH SYNOPSIS
|
|
\fB#include <curses.h>\fR
|
|
.sp
|
|
\fBWINDOW *initscr(void);\fR
|
|
.br
|
|
\fBint endwin(void);\fR
|
|
.sp
|
|
\fBbool isendwin(void);\fR
|
|
.sp
|
|
\fBSCREEN *newterm(const char *\fP\fItype\fP\fB, FILE *\fP\fIoutfd\fP\fB, FILE *\fP\fIinfd\fP\fB);\fR
|
|
.br
|
|
\fBSCREEN *set_term(SCREEN *\fP\fInew\fP\fB);\fR
|
|
.br
|
|
\fBvoid delscreen(SCREEN* \fP\fIsp\fP\fB);\fR
|
|
.br
|
|
.SH DESCRIPTION
|
|
.SS initscr
|
|
\fBinitscr\fR is normally the first \fBcurses\fR routine to call when
|
|
initializing a program.
|
|
A few special routines sometimes need to be called before it;
|
|
these are \fBslk_init\fR(3X), \fBfilter\fR, \fBripoffline\fR,
|
|
\fBuse_env\fR.
|
|
For multiple-terminal applications,
|
|
\fBnewterm\fR may be called before \fBinitscr\fR.
|
|
.PP
|
|
The initscr code determines the terminal type and initializes all \fBcurses\fR
|
|
data structures.
|
|
\fBinitscr\fR also causes the first call to \fBrefresh\fR(3X)
|
|
to clear the screen.
|
|
If errors occur, \fBinitscr\fR writes an appropriate error
|
|
message to standard error and exits;
|
|
otherwise, a pointer is returned to \fBstdscr\fR.
|
|
.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 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
|
|
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$TERM\fR,
|
|
.bP
|
|
a file pointer for output to the terminal, and
|
|
.bP
|
|
another file pointer for input from the terminal
|
|
.PP
|
|
If the \fItype\fR parameter is \fBNULL\fR, \fB$TERM\fR will be used.
|
|
.SS endwin
|
|
.PP
|
|
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.
|
|
.PP
|
|
A program should always call \fBendwin\fR before exiting or escaping from
|
|
\fBcurses\fR mode temporarily.
|
|
This routine
|
|
.bP
|
|
resets colors to correspond with the default color pair 0,
|
|
.bP
|
|
moves the cursor to the lower left-hand corner of the screen,
|
|
.bP
|
|
clears the remainder of the line so that it uses the default colors,
|
|
.bP
|
|
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(3X) or \fBdoupdate\fR(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.
|
|
.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 previous terminal is returned by the routine.
|
|
This is the only routine which manipulates \fBSCREEN\fR 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.
|
|
.SH RETURN VALUE
|
|
\fBendwin\fR returns the integer \fBERR\fR upon failure and \fBOK\fR
|
|
upon successful completion.
|
|
.PP
|
|
Routines that return pointers always return \fBNULL\fR on error.
|
|
.PP
|
|
X/Open defines no error conditions.
|
|
In this implementation
|
|
.bP
|
|
\fBendwin\fP returns an error if the terminal was not initialized.
|
|
.bP
|
|
\fBnewterm\fP
|
|
returns an error 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 PORTABILITY
|
|
These functions were described in the XSI Curses standard, 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:
|
|
.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.
|
|
.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
|
|
.PP
|
|
If the TERM 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:
|
|
.RS 5
|
|
.PP
|
|
\fICurses implementations may provide for special handling of the \fBSIGINT\fP,
|
|
\fBSIGQUIT\fP and \fBSIGTSTP\fP signals
|
|
if their disposition is \fBSIG_DFL\fP at the time
|
|
\fBinitscr\fP is called \fP...
|
|
.PP
|
|
\fIAny 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
|
|
.PP
|
|
\fINone of the Curses functions are required to be safe
|
|
with respect to signals \fP...
|
|
.RE
|
|
.PP
|
|
This implementation establishes signal handlers during initialization,
|
|
e.g., \fBinitscr\fP or \fBnewterm\fP.
|
|
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.
|
|
Although it \fIusually\fP works as expected, there are limitations:
|
|
.RS 5
|
|
.bP
|
|
Walking the \fBSCREEN\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.
|
|
.RE
|
|
.TP 5
|
|
.B SIGTERM
|
|
This uses the same handler as \fBSIGINT\fP, with the same limitations.
|
|
It is not mentioned in X/Open Curses, but is more suitable for this
|
|
purpose than \fBSIGQUIT\fP (which is used in debugging).
|
|
.TP 5
|
|
.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
|
|
assuming that it has been completely altered.
|
|
It also updates the saved terminal modes with \fBdef_shell_mode\fP
|
|
(see \fBcurs_kernel\fR(3X)).
|
|
.TP 5
|
|
.B SIGWINCH
|
|
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
|
|
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).
|