X-Git-Url: https://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=man%2Fresizeterm.3x;h=9ab3b011a1058d27e8f9ade583bc2a20f4c3a57d;hp=ba5ac9836e098b865013bd3fca33602f37bcd127;hb=d62b54c082a8564aa0c715cddadb1160498b057f;hpb=661078ddbde3ce0f3b06e95642fbb9b5fef7dca1;ds=sidebyside diff --git a/man/resizeterm.3x b/man/resizeterm.3x index ba5ac983..9ab3b011 100644 --- a/man/resizeterm.3x +++ b/man/resizeterm.3x @@ -1,5 +1,5 @@ .\"*************************************************************************** -.\" Copyright (c) 1998 Free Software Foundation, Inc. * +.\" Copyright (c) 1998-2015,2017 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 * @@ -26,63 +26,104 @@ .\" authorization. * .\"*************************************************************************** .\" -.\" Author: Thomas E. Dickey 1996,1997 +.\" Author: Thomas E. Dickey 1996-on .\" -.\" $Id: resizeterm.3x,v 1.6 1998/02/11 12:13:48 tom Exp $ +.\" $Id: resizeterm.3x,v 1.22 2017/01/07 19:25:15 tom Exp $ .TH resizeterm 3X "" -. +.de bP +.IP \(bu 4 +.. .SH NAME -\fBresizeterm\fR - change the curses terminal size -. +\fBis_term_resized\fR, +\fBresize_term\fR, +\fBresizeterm\fR \- change the curses terminal size .SH SYNOPSIS \fB#include \fR - +.sp +\fBbool is_term_resized(int lines, int columns);\fR +.br +\fBint resize_term(int lines, int columns);\fR +.br \fBint resizeterm(int lines, int columns);\fR -. .SH DESCRIPTION +.PP This is an extension to the curses library. It provides callers with a hook into the \fBncurses\fR data to resize windows, primarily for use by programs running in an X Window terminal (e.g., xterm). +.SS resizeterm +.PP The function \fBresizeterm\fR resizes the standard and current windows to the specified dimensions, and adjusts other bookkeeping data used by -the \fBncurses\fR library that record the window dimensions. - -When resizing the windows, the function blank-fills the areas that are -extended. The calling application should fill in these areas with -appropriate data. - -The function attempts to resize all windows. +the \fBncurses\fR library that record the window dimensions +such as the \fBLINES\fP and \fBCOLS\fP variables. +.SS resize_term +.PP +Most of the work is done by the inner function \fBresize_term\fR. +The outer function \fBresizeterm\fR adds bookkeeping for the SIGWINCH handler. +When resizing the windows, +\fBresize_term\fR blank-fills the areas that are extended. +The calling application should fill in these areas with appropriate data. +The \fBresize_term\fR function attempts to resize all windows. However, due to the calling convention of pads, it is not possible to resize these without additional interaction with the application. -. +.SS is_term_resized +.PP +A support function \fBis_term_resized\fR is provided so that applications +can check if the \fBresize_term\fR function would modify the window structures. +It returns \fBTRUE\fP if the windows would be modified, and \fBFALSE\fP otherwise. .SH RETURN VALUE -The function returns the integer \fBERR\fR upon failure and \fBOK\fR on success. -It will fail if either of the dimensions less than or equal to zero, -or if an error occurs while (re)allocating memory for the windows. -. +Except as noted, these functions return +the integer \fBERR\fR upon failure and \fBOK\fR on success. +They will fail if either of the dimensions are less than or equal to zero, +or if an error occurs while (re)allocating memory for the windows. .SH NOTES -While this function is intended to be used to support a signal handler -(i.e., for SIGWINCH), care should be taken to avoid invoking it in a +While these functions are intended to be used to support a signal handler +(i.e., for SIGWINCH), care should be taken to avoid invoking them in a context where \fBmalloc\fR or \fBrealloc\fR may have been interrupted, since it uses those functions. -. .PP If ncurses is configured to supply its own SIGWINCH handler, -the \fBresizeterm\fR function ungetch's a \fBKEY_RESIZE\fR which -will be read on the next call to \fBgetch\fR. -This is used to alert an application that the screen size has changed, +.bP +on receipt of a SIGWINCH, the handler sets a flag +.bP +which is tested in \fBwgetch\fP(3X) and \fBdoupdate\fP, +.bP +in turn, calling the \fBresizeterm\fR function, +.bP +which \fBungetch\fP's a \fBKEY_RESIZE\fR which +will be read on the next call to \fBwgetch\fR. +.IP +The \fBKEY_RESIZE\fP alerts an application that the screen size has changed, and that it should repaint special features such as pads that cannot be done automatically. -. +.IP +Calling \fBresizeterm\fP or \fBresize_term\fP +directly from a signal handler is unsafe. +This indirect method is used to provide a safe way to resize the ncurses +data structures. +.PP +If the environment variables \fBLINES\fP or \fBCOLUMNS\fP are set, +this overrides the library's use of the window size obtained from +the operating system. +Thus, even if a SIGWINCH is received, +no screen size change may be recorded. +.SH PORTABILITY +.PP +It is possible to resize the screen with SVr4 curses, +by +.bP +exiting curses with \fBendwin\fP(3X) and +.bP +resuming using \fBrefresh\fP(3X). +.PP +Doing that clears the screen and is visually distracting. +.PP +This extension of ncurses was introduced in mid-1995. +It was adopted in NetBSD curses (2001) and PDCurses (2003). .SH SEE ALSO +\fBcurs_getch\fR(3X), +\fBcurs_variables\fR(3X), \fBwresize\fR(3X). -. .SH AUTHOR Thomas Dickey (from an equivalent function written in 1988 for BSD curses). -.\"# -.\"# The following sets edit modes for GNU EMACS -.\"# Local Variables: -.\"# mode:nroff -.\"# fill-column:79 -.\"# End: