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42 <H1 class="no-header">curs_scr_dump 3x 2024-06-01 ncurses 6.5 Library calls</H1>
44 <STRONG><A HREF="curs_scr_dump.3x.html">curs_scr_dump(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_scr_dump.3x.html">curs_scr_dump(3x)</A></STRONG>
49 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
50 <STRONG>scr_dump</STRONG>, <STRONG>scr_restore</STRONG>, <STRONG>scr_init</STRONG>, <STRONG>scr_set</STRONG> - read/write a <EM>curses</EM> screen
54 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
55 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
57 <STRONG>int</STRONG> <STRONG>scr_dump(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG> <EM>filename</EM><STRONG>);</STRONG>
58 <STRONG>int</STRONG> <STRONG>scr_restore(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG> <EM>filename</EM><STRONG>);</STRONG>
59 <STRONG>int</STRONG> <STRONG>scr_init(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG> <EM>filename</EM><STRONG>);</STRONG>
60 <STRONG>int</STRONG> <STRONG>scr_set(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG> <EM>filename</EM><STRONG>);</STRONG>
63 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
64 <EM>curses</EM> provides applications the ability to write the contents of the
65 screen to a file and read them back. To read/write a window (rather
66 than the whole screen) from/to a file, use <STRONG><A HREF="curs_util.3x.html">getwin(3x)</A></STRONG> and <STRONG><A HREF="curs_util.3x.html">putwin(3x)</A></STRONG>,
70 </PRE><H3><a name="h3-scr_dump">scr_dump</a></H3><PRE>
71 <STRONG>scr_dump</STRONG> writes to <EM>filename</EM> the contents of the virtual screen; see
72 <STRONG><A HREF="curs_variables.3x.html">curscr(3x)</A></STRONG>.
75 </PRE><H3><a name="h3-scr_restore">scr_restore</a></H3><PRE>
76 <STRONG>scr_restore</STRONG> updates the virtual screen to match the contents of
77 <EM>filename</EM> (if validly written with <STRONG>scr_dump</STRONG>). <EM>curses</EM> does not perform a
78 refresh; after making any desired changes, call <STRONG><A HREF="curs_refresh.3x.html">doupdate(3x)</A></STRONG> or
82 </PRE><H3><a name="h3-scr_init">scr_init</a></H3><PRE>
83 <STRONG>scr_init</STRONG> reads <EM>filename</EM>, using it to initialize <EM>curses</EM> data structures
84 describing the state of the terminal screen. <EM>curses</EM> then, if it
85 decides the terminal state is valid, bases its next update of the
86 screen on this information rather than clearing it and starting from
89 <EM>curses</EM> regards the terminal being in an invalid state for computation
90 of updates based on the contents of <EM>filename</EM> if
92 <STRONG>o</STRONG> the terminal type supports the <EM>terminfo</EM> capabilities <STRONG>exit_ca_mode</STRONG>
93 (<STRONG>rmcup</STRONG>) or <STRONG>non_rev_rmcup</STRONG> (<STRONG>nrrmc</STRONG>), or
95 <STRONG>o</STRONG> <EM>curses</EM> knows that the terminal has been written to since the
96 preceding <STRONG>scr_dump</STRONG> call.
98 Either of the foregoing conditions means that <EM>curses</EM> cannot assume that
99 the terminal's contents match their representation in <EM>filename</EM>. The
100 former is due to terminal features (such as <STRONG>xterm(1)</STRONG>'s "alternate
101 screen") that couple cursor-positioning mode with a local cache of
102 screen contents. <EM>curses</EM> cannot know whether terminal is displaying
103 from that local cache at the time the application calls <STRONG>scr_init</STRONG>, so it
104 makes a pessimistic assumption that a full redraw is required; see
105 subsection "Cursor Motions" of <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>.
107 <STRONG>scr_init</STRONG> could be used after <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG> or <STRONG>system(3)</STRONG> to share the
108 screen with another process that has done a <STRONG>scr_dump</STRONG> after <STRONG><A HREF="curs_initscr.3x.html">endwin(3x)</A></STRONG>.
109 An application that supports suspending its state on exit and
110 subsequent resumption upon later execution might use <STRONG>scr_dump</STRONG> and
111 <STRONG>scr_init</STRONG> thus.
114 </PRE><H3><a name="h3-scr_set">scr_set</a></H3><PRE>
115 <STRONG>scr_set</STRONG> combines <STRONG>scr_restore</STRONG> and <STRONG>scr_init</STRONG>, synchronizing the contents
116 of <EM>filename</EM> with the virtual screen. It can be regarded as a screen
117 inheritance function; consider a real-time screen-sharing application.
120 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
121 These functions return <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on failure.
123 In <EM>ncurses</EM>, each function returns <STRONG>ERR</STRONG> if it cannot open <EM>filename</EM>.
124 <STRONG>scr_init</STRONG>, <STRONG>scr_restore</STRONG>, and <STRONG>scr_set</STRONG> return <STRONG>ERR</STRONG> if the contents of
125 <EM>filename</EM> are invalid.
128 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
129 <STRONG>scr_init</STRONG>, <STRONG>scr_restore</STRONG>, and <STRONG>scr_set</STRONG> may be implemented as macros.
132 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
133 X/Open Curses, Issue 4 describes these functions. It specifies no
134 error conditions for them.
136 SVr4 omitted the <EM>const</EM> qualifiers.
138 SVr4 documentation describes <STRONG>scr_init</STRONG> such that the dump data is also
139 considered invalid "if the time-stamp of the tty is old" but does not
143 </PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
144 SVr3 (1987) introduced <STRONG>scr_dump</STRONG>, <STRONG>scr_init</STRONG>, and <STRONG>scr_restore</STRONG>. SVr3.1
145 added <STRONG>scr_set</STRONG>.
148 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
149 <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>,
150 <STRONG>system(3)</STRONG>, <STRONG><A HREF="scr_dump.5.html">scr_dump(5)</A></STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>
154 ncurses 6.5 2024-06-01 <STRONG><A HREF="curs_scr_dump.3x.html">curs_scr_dump(3x)</A></STRONG>
158 <li><a href="#h2-NAME">NAME</a></li>
159 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
160 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
162 <li><a href="#h3-scr_dump">scr_dump</a></li>
163 <li><a href="#h3-scr_restore">scr_restore</a></li>
164 <li><a href="#h3-scr_init">scr_init</a></li>
165 <li><a href="#h3-scr_set">scr_set</a></li>
168 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
169 <li><a href="#h2-NOTES">NOTES</a></li>
170 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
171 <li><a href="#h2-HISTORY">HISTORY</a></li>
172 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>