+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+
+</PRE><H3><a name="h3-filter">filter</a></H3><PRE>
+ The SVr4 documentation describes the action of <STRONG>filter</STRONG> only in the
+ vaguest terms. The description here is adapted from X/Open Curses
+ (which erroneously fails to describe the disabling of <STRONG>cuu</STRONG>).
+
+
+</PRE><H3><a name="h3-delay_output-padding">delay_output padding</a></H3><PRE>
+ The limitation to 30 seconds and the use of <STRONG>napms</STRONG> differ from other
+ implementations.
+
+ <STRONG>o</STRONG> SVr4 curses does not delay if no padding character is available.
+
+ <STRONG>o</STRONG> NetBSD curses uses <STRONG>napms</STRONG> when no padding character is available,
+ but does not take timing into account when using the padding
+ character.
+
+ Neither limits the delay.
+
+
+</PRE><H3><a name="h3-keyname">keyname</a></H3><PRE>
+ The <STRONG>keyname</STRONG> function may return the names of user-defined string
+ capabilities which are defined in the terminfo entry via the <STRONG>-x</STRONG> option
+ of <STRONG>tic</STRONG>. This implementation automatically assigns at run-time keycodes
+ to user-defined strings which begin with "k". The keycodes start at
+ KEY_MAX, but are not guaranteed to be the same value for different runs
+ because user-defined codes are merged from all terminal descriptions
+ which have been loaded. The <STRONG><A HREF="curs_extend.3x.html">use_extended_names(3x)</A></STRONG> function controls
+ whether this data is loaded when the terminal description is read by
+ the library.
+
+
+</PRE><H3><a name="h3-nofilter_use_tioctl">nofilter, use_tioctl</a></H3><PRE>
+ The <STRONG>nofilter</STRONG> and <STRONG>use_tioctl</STRONG> routines are specific to <EM>ncurses</EM>. They
+ were not supported on Version 7, BSD or System V implementations. It
+ is recommended that any code depending on <EM>ncurses</EM> extensions be
+ conditioned using <STRONG>NCURSES_VERSION</STRONG>.
+
+
+</PRE><H3><a name="h3-putwin_getwin-file-format">putwin/getwin file-format</a></H3><PRE>
+ The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions have several issues with portability:
+
+ <STRONG>o</STRONG> The files written and read by these functions use an
+ implementation-specific format. Although the format is an obvious
+ target for standardization, it has been overlooked.
+
+ Interestingly enough, according to the copyright dates in Solaris
+ source, the functions (along with <STRONG>scr_init</STRONG>, etc.) originated with
+ the University of California, Berkeley (in 1982) and were later (in
+ 1988) incorporated into SVr4. Oddly, there are no such functions
+ in the 4.3BSD curses sources.
+
+ <STRONG>o</STRONG> Most implementations simply dump the binary <EM>WINDOW</EM> structure to the
+ file. These include SVr4 curses, NetBSD and PDCurses, as well as
+ older <EM>ncurses</EM> versions. This implementation (as well as the X/Open
+ variant of Solaris curses, dated 1995) uses textual dumps.
+
+ The implementations which use binary dumps use block-I/O (the
+ <STRONG>fwrite</STRONG> and <STRONG>fread</STRONG> functions). Those that use textual dumps use
+ buffered-I/O. A few applications may happen to write extra data in
+ the file using these functions. Doing that can run into problems
+ mixing block- and buffered-I/O. This implementation reduces the
+ problem on writes by flushing the output. However, reading from a
+ file written using mixed schemes may not be successful.
+
+
+</PRE><H3><a name="h3-unctrl_wunctrl">unctrl, wunctrl</a></H3><PRE>
+ X/Open Curses, Issue 4 describes these functions. It states that
+ <STRONG>unctrl</STRONG> and <STRONG>wunctrl</STRONG> will return a null pointer if unsuccessful, but does
+ not define any error conditions. This implementation checks for three
+ cases:
+
+ <STRONG>o</STRONG> the parameter is a 7-bit US-ASCII code. This is the case that
+ X/Open Curses documented.
+
+ <STRONG>o</STRONG> the parameter is in the range 128-159, i.e., a C1 control code. If
+ <STRONG><A HREF="legacy_coding.3x.html">use_legacy_coding(3x)</A></STRONG> has been called with a <STRONG>2</STRONG> parameter, <STRONG>unctrl</STRONG>
+ returns the parameter, i.e., a one-character string with the
+ parameter as the first character. Otherwise, it returns "~@",
+ "~A", etc., analogous to "^@", "^A", C0 controls.
+
+ X/Open Curses does not document whether <STRONG>unctrl</STRONG> can be called before
+ initializing curses. This implementation permits that, and returns
+ the "~@", etc., values in that case.
+
+ <STRONG>o</STRONG> parameter values outside the 0 to 255 range. <STRONG>unctrl</STRONG> returns a null
+ pointer.
+
+ The strings returned by <STRONG>unctrl</STRONG> in this implementation are determined at
+ compile time, showing C1 controls from the upper-128 codes with a "~"
+ prefix rather than "^". Other implementations have different
+ conventions. For example, they may show both sets of control
+ characters with "^", and strip the parameter to 7 bits. Or they may
+ ignore C1 controls and treat all of the upper-128 codes as printable.
+ This implementation uses 8 bits but does not modify the string to
+ reflect locale. The <STRONG><A HREF="legacy_coding.3x.html">use_legacy_coding(3x)</A></STRONG> function allows the caller
+ to change the output of <STRONG>unctrl</STRONG>.
+
+ Likewise, the <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> function allows the caller to change the output
+ of <STRONG>keyname</STRONG>, i.e., it determines whether to use the "M-" prefix for
+ "meta" keys (codes in the range 128 to 255). Both
+ <STRONG><A HREF="legacy_coding.3x.html">use_legacy_coding(3x)</A></STRONG> and <STRONG><A HREF="curs_inopts.3x.html">meta(3x)</A></STRONG> succeed only after curses is
+ initialized. X/Open Curses does not document the treatment of codes
+ 128 to 159. When treating them as "meta" keys (or if <STRONG>keyname</STRONG> is called
+ before initializing curses), this implementation returns strings
+ "M-^@", "M-^A", etc.
+
+ X/Open Curses documents <STRONG>unctrl</STRONG> as declared in <STRONG><unctrl.h></STRONG>, which <EM>ncurses</EM>
+ does. However, <EM>ncurses</EM>' <STRONG><curses.h></STRONG> includes <STRONG><unctrl.h></STRONG>, matching the
+ behavior of SVr4 curses. Other implementations may not do that.
+
+
+</PRE><H3><a name="h3-use_env_use_tioctl">use_env, use_tioctl</a></H3><PRE>
+ If <EM>ncurses</EM> is configured to provide the sp-functions extension, the
+ state of <STRONG>use_env</STRONG> and <STRONG>use_tioctl</STRONG> may be updated before creating each
+ <EM>screen</EM> rather than once only (<STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>). This feature of
+ <STRONG>use_env</STRONG> is not provided by other implementations of curses.
+
+
+</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
+ <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_inopts.3x.html">curs_inopts(3x)</A></STRONG>, <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>,
+ <STRONG><A HREF="curs_scr_dump.3x.html">curs_scr_dump(3x)</A></STRONG>, <STRONG><A HREF="curs_sp_funcs.3x.html">curs_sp_funcs(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>,
+ <STRONG><A HREF="legacy_coding.3x.html">legacy_coding(3x)</A></STRONG>