ncurses 6.4 - patch 20240224

[ncurses.git] / man / curs_terminfo.3x

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.\" $Id: curs_terminfo.3x,v 1.130 2024/02/24 20:04:09 tom Exp $
.TH curs_terminfo 3X 2024-02-24 "ncurses 6.4" "Library calls"
.ie \n(.g \{\
.ds `` \(lq
.ds '' \(rq
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.el \{\
.ie t .ds `` ``
.el   .ds `` ""
.ie t .ds '' ''
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.de bP
.ie n  .IP \(bu 4
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.
.SH NAME
\fB\%del_curterm\fP,
\fB\%mvcur\fP,
\fB\%putp\fP,
\fB\%restartterm\fP,
\fB\%set_curterm\fP,
\fB\%setupterm\fP,
\fB\%tigetflag\fP,
\fB\%tigetnum\fP,
\fB\%tigetstr\fP,
\fB\%tiparm\fP,
\fB\%tiparm_s\fP,
\fB\%tiscan_s\fP,
\fB\%tparm\fP,
\fB\%tputs\fP,
\fB\%vid_attr\fP,
\fB\%vid_puts\fP,
\fB\%vidattr\fP,
\fB\%vidputs\fP \-
\fIcurses\fR interfaces to \fI\%term\%info\fR database
.SH SYNOPSIS
.nf
\fB#include <curses.h>
\fB#include <term.h>
.PP
\fBTERMINAL *cur_term;
.PP
\fBconst char * const boolnames[];
\fBconst char * const boolcodes[];
\fBconst char * const boolfnames[];
\fBconst char * const numnames[];
\fBconst char * const numcodes[];
\fBconst char * const numfnames[];
\fBconst char * const strnames[];
\fBconst char * const strcodes[];
\fBconst char * const strfnames[];
.PP
\fBint setupterm(const char *\fIterm\fP, int \fIfiledes\fP, int *\fIerrret\fP);
\fBTERMINAL *set_curterm(TERMINAL *\fInterm\fP);
\fBint del_curterm(TERMINAL *\fIoterm\fP);
\fBint restartterm(const char *\fIterm\fP, int \fIfiledes\fP, int *\fIerrret\fP);
.PP
\fBchar *tparm(const char *\fIstr\fP, \fR.\|.\|.\fP);
        \fI/* or */
\fBchar *tparm(const char *\fIstr\fP, long \fIp1\fP \fR.\|.\|.\fP \fBlong\fP \fIp9\fP);
.PP
\fBint tputs(const char *\fIstr\fP, int \fIaffcnt\fP, int (*\fIputc\fP)(int));
\fBint putp(const char *\fIstr\fP);
.PP
\fBint vidputs(chtype \fIattrs\fP, int (*\fIputc\fP)(int));
\fBint vidattr(chtype \fIattrs\fP);
\fBint vid_puts(attr_t \fIattrs\fP, short \fIpair\fP, void *\fIopts\fP, int (*\fIputc\fP)(int));
\fBint vid_attr(attr_t \fIattrs\fP, short \fIpair\fP, void *\fIopts\fP);
.PP
\fBint mvcur(int \fIoldrow\fP, int \fIoldcol\fP, int \fInewrow\fP, int \fInewcol\fP);
.PP
\fBint tigetflag(const char *\fIcap-code\fP);
\fBint tigetnum(const char *\fIcap-code\fP);
\fBchar *tigetstr(const char *\fIcap-code\fP);
.PP
\fBchar *tiparm(const char *\fIstr\fP, \fR.\|.\|.\fP);
.PP
\fI/* extensions */
\fBchar *tiparm_s(int \fIexpected\fP, int \fImask\fP, const char *\fIstr\fP, ...);
\fBint tiscan_s(int *\fIexpected\fP, int *\fImask\fP, const char *\fIstr\fP);
.PP
\fI/* deprecated */
\fBint setterm(const char *\fIterm\fP);
.fi
.SH DESCRIPTION
These low-level functions must be called by programs that deal directly
with the
.I \%term\%info
database to handle certain terminal capabilities,
such as programming function keys.
For all other functionality,
.I curses
functions are more suitable and their use is recommended.
.PP
None of these functions use
(or are aware of)
multibyte character strings such as UTF-8.
.bP
Capability names and codes use the POSIX portable character set.
.bP
Capability string values have no associated encoding;
they are strings of 8-bit characters.
.SS Initialization
Initially,
\fB\%setupterm\fP should be called.
The high-level
.I curses
functions \fB\%initscr\fP and \fB\%newterm\fP call \fB\%setupterm\fP to
initialize the low-level set of terminal-dependent variables listed in
\fB\%term_variables\fP(3X).
.PP
Applications can use the terminal capabilities either directly
(via header definitions),
or by special functions.
The header files
.I \%curses.h
and
.I \%term.h
should be included
(in that order)
to get the definitions for these strings,
numbers,
and flags.
.PP
The
.I \%term\%info
variables
.B \%lines
and
.B \%columns
are initialized by \fB\%setupterm\fP as follows.
.bP
If \fB\%use_env(FALSE)\fP has been called,
values for
.B \%lines
and
.B \%columns
specified in
.I \%term\%info
are used.
.bP
Otherwise,
if the environment variables
.I LINES
and
.I \%COLUMNS
exist,
their values are used.
If these environment variables do not exist and the program is running
in a window,
the current window size
is used.
Otherwise,
if the environment variables do not exist,
the values for
.B \%lines
and
.B \%columns
specified in the
.I \%term\%info
database are used.
.PP
Parameterized strings should be passed through \fB\%tparm\fP to
instantiate them.
All
.I \%term\%info
strings
(including the output of \fB\%tparm\fP)
should be sent to the terminal device with \fB\%tputs\fP or
\fB\%putp\fP.
Call \fB\%reset_shell_mode\fP to restore the terminal modes before
exiting;
see \fB\%curs_kernel\fP(3X).
.PP
Programs that use
cursor addressing should
.bP
output \fB\%enter_ca_mode\fP upon startup and
.bP
output \fB\%exit_ca_mode\fP before exiting.
.PP
Programs that execute shell subprocesses should
.bP
call \fB\%reset_shell_mode\fP and
output \fB\%exit_ca_mode\fP before the shell
is called and
.bP
output \fB\%enter_ca_mode\fP and
call \fB\%reset_prog_mode\fP after returning from the shell.
.PP
\fB\%setupterm\fP reads in the
.I \%term\%info
database,
initializing the
.I \%term\%info
structures,
but does not set up the output virtualization structures used by
.I curses.
Its parameters follow.
.RS 3
.TP 5
.I term
is the terminal type,
a character string.
If
.I term
is null,
the environment variable
.I TERM
is read.
.TP 5
.I filedes
is the file descriptor used for getting and setting terminal I/O modes.
.IP
Higher-level applications use \fB\%newterm\fP(3X) to initialize the
terminal,
passing an output
.I stream
rather than a
.I descriptor.
In
.I curses,
the two are the same because \fB\%newterm\fP calls \fB\%setupterm\fP,
passing the file descriptor derived from its output stream parameter.
.TP 5
.I errret
points to an optional location where an error status can be returned to
the caller.
If
.I errret
is not null,
then \fB\%setupterm\fP returns
.B OK
or
.B ERR
and stores a status value in the integer pointed to by
.I errret.
A return value of
.B OK
combined with status of
.B 1
in
.I errret
is normal.
.IP
If
.B ERR
is returned,
examine
.I errret:
.RS
.TP 5
.B 1
means that the terminal is hardcopy,
and cannot be used for
.I curses
applications.
.IP
\fB\%setupterm\fP determines if the entry is a hardcopy type by
checking the
.B \%hardcopy
.RB ( hc )
capability.
.TP 5
.B 0
means that the terminal could not be found,
or that it is a generic type,
having too little information for
.I curses
applications to run.
.IP
\fB\%setupterm\fP determines if the entry is a generic type by
checking the
.B \%generic_type
.RB ( gn )
capability.
.TP 5
.B \-1
means that the
.I \%term\%info
database could not be found.
.RE
.IP
If
.I errret
is null,
\fB\%setupterm\fP reports an error message upon finding an error and
exits.
Thus,
the simplest call is:
.RS
.IP
.EX
setupterm((char *)0, 1, (int *)0);
.EE
.RE
.IP
which uses all the defaults and sends the output to
.BR stdout .
.RE
.\" ********************************************************************
.SS "The Terminal State"
\fB\%setupterm\fP stores its information about the terminal in a
.I \%TERMINAL
structure pointed to by the global variable \fB\%cur_term\fP.
If it detects an error,
or decides that the terminal is unsuitable
(hardcopy or generic),
it discards this information,
making it not available to applications.
.PP
If \fB\%setupterm\fP is called repeatedly for the same terminal type,
it will reuse the information.
It maintains only one copy of a given terminal's capabilities in memory.
If it is called for different terminal types,
\fB\%setupterm\fP allocates new storage for each set of terminal
capabilities.
.PP
\fB\%set_curterm\fP sets \fB\%cur_term\fP to
.I \%nterm,
and makes all of the
.I \%term\%info
Boolean,
numeric,
and string variables use the values from
.I \%nterm.
It returns the old value of \fB\%cur_term\fP.
.PP
\fB\%del_curterm\fP frees the space pointed to by
.I \%oterm
and makes it available for further use.
If
.I \%oterm
is
the same as \fB\%cur_term\fP,
references to any of the
.I \%term\%info
Boolean,
numeric,
and string variables thereafter may refer to invalid memory locations
until another \fB\%setupterm\fP has been called.
.PP
\fB\%restartterm\fP is similar to \fB\%setupterm\fP and \fB\%initscr\fP,
except that it is called after restoring memory to a previous state
(for example,
when reloading a game saved as a core image dump).
\fB\%restartterm\fP assumes that the windows and the input and output
options are the same as when memory was saved,
but the terminal type and baud rate may be different.
Accordingly,
\fB\%restartterm\fP saves various terminal state bits,
calls \fB\%setupterm\fP,
and then restores the bits.
.\" ********************************************************************
.SS "Formatting Output"
\fB\%tparm\fP instantiates the string
.I str
with parameters
.I pi.
A pointer is returned to the result of
.I str
with the parameters applied.
Application developers should keep in mind these quirks of the
interface:
.bP
Although \fB\%tparm\fP's actual parameters may be integers or strings,
the prototype expects
.I long
(integer) values.
.bP
Aside from the
.B \%set_attributes\fP
.RB ( sgr )
capability,
most terminal capabilities require no more than one or two parameters.
.bP
Padding information is ignored by \fB\%tparm\fP;
it is interpreted by \fB\%tputs\fP.
.bP
The capability string is null-terminated.
Use \*(``\e200\*('' where an ASCII NUL is needed in the output.
.PP
\fB\%tiparm\fP is a newer form of \fB\%tparm\fP which uses
.I \%stdarg.h
rather than a fixed-parameter list.
Its numeric parameters are
.IR int s
rather than
.IR long s.
.PP
Both \fB\%tparm\fP and \fB\%tiparm\fP assume that the application passes
parameters consistent with the terminal description.
Two extensions are provided as alternatives to deal with untrusted data.
.bP
\fB\%tiparm_s\fP is an extension which is a safer formatting function
than \fB\%tparm\fR or \fB\%tiparm\fR,
because it allows the developer to tell the
.I curses
library how many parameters to expect in the parameter list,
and which may be string parameters.
.IP
The \fImask\fP parameter has one bit set for each of the parameters
(up to 9)
passed as
.I char
pointers rather than numbers.
.bP
The extension \fB\%tiscan_s\fP allows the application to inspect a
formatting capability to see what the
.I curses
library would assume.
.\" ********************************************************************
.SS "Output Functions"
String capabilities can contain padding information,
a time delay
(accommodating performance limitations of hardware terminals)
expressed as \fB$<\fIn\fB>\fR,
where \fIn\fP is a nonnegative integral count of milliseconds.
If \fIn\fP exceeds 30,000
(thirty seconds),
it is capped at that value.
.PP
\fB\%tputs\fP interprets time-delay information in the string
.I str
and outputs it,
executing the delays:
.bP
The
.I str
parameter must be a
.I \%term\%info
string variable or the return value of
\fB\%tparm\fP,
\fB\%tiparm\fP,
\fB\%tgetstr\fP,
or \fB\%tgoto\fP.
.IP
The \fB\%tgetstr\fP and \fB\%tgoto\fP functions are part of the
.I termcap
interface,
which happens to share these function names with the
.I \%term\%info
API.
.bP
.I affcnt
is the number of lines affected,
or
.B 1
if not applicable.
.bP
.I putc
is a
.IR \%putchar -like
function to which the characters are passed,
one at a time.
.IP
If \fB\%tputs\fP processes a time-delay,
it uses the \fB\%delay_output\fP(3X) function,
routing any resulting padding characters through this function.
.PP
\fB\%putp\fR calls
.RB \%\*(`` tputs(\c
.IB str ", 1, putchar)\c"
\*(''.
The output of \fB\%putp\fP always goes to
.BR stdout ,
rather than the
.I \%file\%des
specified in \fB\%setupterm\fP.
.PP
\fB\%vidputs\fP displays the string on the terminal in the video
attribute mode
.I attrs,
which is any combination of the attributes listed in \fB\%curses\fP(3X).
The characters are passed to the
.IR \%putchar -like
function
.I putc.
.PP
\fB\%vidattr\fP is like \fB\%vidputs\fP,
except that it outputs through \fI\%putchar\fP(3).
.PP
.B \%vid_attr
and
.B \%vid_puts
correspond to
.B \%vidattr
and
.BR \%vidputs ,
respectively.
They use multiple parameters to represent the character attributes and
color;
namely,
.bP
.I \%attrs,
of type
.I \%attr_t,
for the attributes and
.bP
.I pair,
of type
.I short,
for the color pair number.
.PP
Use the attribute constants prefixed with
.RB \*(`` WA_ \*(''
with
.B \%vid_attr
and
.BR \%vid_puts .
.PP
X/Open Curses reserves the
.I opts
argument for future use,
saying that applications must provide a null pointer for that argument;
but see section \*(``EXTENSIONS\*('' below.
.PP
\fB\%mvcur\fP provides low-level cursor motion.
It takes effect immediately
(rather than at the next refresh).
Unlike the other low-level output functions,
which either write to the standard output or pass an output function
parameter,
\fB\%mvcur\fP uses an output file descriptor derived from
the output stream parameter of \fB\%newterm\fP(3X).
.PP
While \fB\%putp\fP and \fB\%mvcur\fP are low-level functions that do not
use high-level
.I curses
state,
.I \%ncurses
declares them in
.I \%curses.h
because System\ V did this
(see section \*(``HISTORY\*('' below).
.\" ********************************************************************
.SS "Terminal Capability Functions"
\fB\%tigetflag\fP,
\fB\%tigetnum\fP,
and \fB\%tigetstr\fP return the value of the capability corresponding to
the
.I \%term\%info
.I cap-code,
such as
.BR xenl ,
passed to them.
The
.I cap-code
for each capability is given in the table column entitled
.I cap-code
code in the capabilities section of \fB\%terminfo\fP(5).
.PP
These functions return special values to denote errors.
.PP
\fB\%tigetflag\fP returns
.TP
.B \-1
if
.I cap-code
is not a Boolean capability,
or
.TP
.B 0
if it is canceled or absent from the terminal description.
.PP
\fB\%tigetnum\fP returns
.TP
.B \-2
if
.I cap-code
is not a numeric capability,
or
.TP
.B \-1
if it is canceled or absent from the terminal description.
.PP
\fB\%tigetstr\fP returns
.TP
.B "(char *)\-1"
if
.I cap-code
is not a string capability,
or
.TP
.B 0
if it is canceled or absent from the terminal description.
.\" ********************************************************************
.SS "Terminal Capability Names"
These null-terminated arrays contain
.bP
the short \fI\%term\%info\fP names (\*(``codes\*(''),
.bP
the \fItermcap\fP names (\*(``names\*(''),
and
.bP
the long \fI\%term\%info\fP names (\*(``fnames\*('')
.PP
for each of the predefined
.I \%term\%info
variables:
.PP
.RS
.nf
\fBconst char *boolnames[]\fP, \fB*boolcodes[]\fP, \fB*boolfnames[]\fP
\fBconst char *numnames[]\fP, \fB*numcodes[]\fP, \fB*numfnames[]\fP
\fBconst char *strnames[]\fP, \fB*strcodes[]\fP, \fB*strfnames[]\fP
.fi
.RE
.\" ********************************************************************
.SS "Releasing Memory"
Each successful call to \fB\%setupterm\fP allocates memory to hold the
terminal description.
As a side effect,
it sets \fB\%cur_term\fP to point to this memory.
If an application calls
.IP
.EX
del_curterm(cur_term);
.EE
.PP
the memory will be freed.
.PP
The formatting functions \fB\%tparm\fP and \fB\%tiparm\fP extend the
storage allocated by \fB\%setupterm\fP as follows.
.bP
They add the \*(``static\*(''
.I \%term\%info
variables [a-z].
Before
.I \%ncurses
6.3,
those were shared by all screens.
With
.I \%ncurses
6.3,
those are allocated per screen.
See \fB\%terminfo\fP(5).
.bP
To improve performance,
.I \%ncurses
6.3 caches the result of analyzing
.I \%term\%info
strings for their parameter types.
That is stored as a binary tree referenced from the
.I \%TERMINAL
structure.
.PP
The higher-level \fB\%initscr\fP and \fB\%newterm\fP functions use
\fB\%setupterm\fP.
Normally they do not free this memory,
but it is possible to do that using the \fB\%delscreen\fP(3X) function.
.\" ********************************************************************
.SH RETURN VALUE
X/Open Curses defines no failure conditions.
In
.I \%ncurses,
.TP 5
.B del_curtem
fails if its terminal parameter is null.
.TP 5
.B putp
calls \fB\%tputs\fP,
returning the same error codes.
.TP 5
.B restartterm
fails if the associated call to \fB\%setupterm\fP returns an error.
.TP 5
.B setupterm
fails if it cannot allocate enough memory,
or create the initial windows
.RB ( \%stdscr ,
.BR \%curscr ,
and
.BR \%newscr )
Other error conditions are documented above.
.TP 5
.B tparm
returns a null pointer if the capability would require unexpected
parameters;
that is,
too many,
too few,
or incorrect types
(strings where integers are expected,
or vice versa).
.TP 5
.B tputs
fails if the string parameter is null.
It does not detect I/O errors:
X/Open Curses states that \fB\%tputs\fP ignores the return value
of the output function \fI\%putc\fP.
.\" ********************************************************************
.SH NOTES
The
.B \%vid_attr
function in
.I \%ncurses
is a special case.
It was originally implemented based on a draft of X/Open Curses,
as a macro,
before other parts of the
.I \%ncurses
wide-character API were developed,
and unlike the other wide-character functions,
is also provided in the non-wide-character configuration.
.\" ********************************************************************
.SH EXTENSIONS
The functions marked as extensions were designed for
.I \%ncurses,
and are not found in SVr4
.IR curses ,
4.4BSD
.IR curses ,
or any other previous
.I curses
implementation.
.PP
.I \%ncurses
allows
.I opts
to be a pointer to
.I int,
which overrides the
.I pair
.RI ( short )
argument.
.\" ********************************************************************
.SH PORTABILITY
\fB\%setterm\fP is not described by X/Open and must be considered
non-portable.
All other functions are as described by X/Open.
.SS "Compatibility Macros"
This implementation provides a few macros for compatibility with systems
before SVr4
(see section \*(``HISTORY\*('' below).
They include
\fB\%Bcrmode\fP,
\fB\%Bfixterm\fP,
\fB\%Bgettmode\fP,
\fB\%Bnocrmode\fP,
\fB\%Bresetterm\fP,
\fB\%Bsaveterm\fP,
and
\fB\%Bsetterm\fP.
.PP
In SVr4,
these are found in
.IR \%curses.h ,
but except for \fB\%setterm\fP,
are likewise macros.
The one function,
\fB\%setterm\fP,
is mentioned in the manual page.
It further notes that \fB\%setterm\fP was replaced by \fB\%setupterm\fP,
stating that the call
.RS
.EX
setupterm(\fIterm\fP, 1, (int *)0)
.EE
.RE
provides the same functionality as \fB\%setterm(\fIterm\fB)\fR,
discouraging the latter for new programs.
.I \%ncurses
implements each of these symbols as macros for BSD
.I curses
compatibility.
.SS "Legacy Data"
\fB\%setupterm\fP copies the terminal name to the array \fB\%ttytype\fP.
This is not part of X/Open Curses,
but is assumed by some applications.
.PP
Other implementions may not declare the capability name arrays.
Some provide them without declaring them.
X/Open does not specify them.
.PP
Extended terminal capability names,
as defined by
.RB \%\*(`` "@TIC@ \-x" \*('',
are not stored in the arrays described here.
.SS "Output Buffering"
Older versions of \fI\%ncurses\fP assumed that the file descriptor
passed to \fB\%setupterm\fP from \fB\%initscr\fP or \fB\%newterm\fP uses
buffered I/O,
and would write to the corresponding stream.
In addition to the limitation that the terminal was left in
block-buffered mode on exit
(like System\ V
.IR curses ),
it was problematic because
.I \%ncurses
did not allow a reliable way to clean up on receiving
.BR SIGTSTP .
.PP
The current version (ncurses6)
uses output buffers managed directly by
.I \%ncurses.
Some of the low-level functions described in this manual page write
to the standard output.
They are not signal-safe.
The high-level functions in
.I \%ncurses
employ alternate versions of these functions using the more reliable
buffering scheme.
.SS "Function Prototypes"
The X/Open Curses prototypes are based on the SVr4
.I curses
header declarations,
which were defined at the same time the C language was first
standardized in the late 1980s.
.bP
X/Open Curses uses
.I \%const
less effectively than a later design might,
in some cases applying it needlessly to values are already constant,
and in most cases overlooking parameters which normally would use
.I \%const.
Using constant parameters for functions which do not use
.I \%const
may prevent the program from compiling.
On the other hand,
\*(``writable strings\*('' are an obsolescent feature.
.IP
As an extension,
this implementation can be configured to change the function prototypes
to use the
.I \%const
keyword.
The
.I \%ncurses
ABI 6 enables this feature by default.
.bP
X/Open Curses prototypes \fB\%tparm\fP with a fixed number of
parameters,
rather than a variable argument list.
.IP
This implementation uses a variable argument list,
but can be configured to use the fixed-parameter list.
Portable applications should provide nine parameters after the format;
zeroes are fine for this purpose.
.IP
In response to review comments by Thomas E. Dickey,
X/Open Curses Issue 7 proposed the \fB\%tiparm\fP function in mid-2009.
.IP
While \fB\%tiparm\fP is always provided in \fI\%ncurses\fP,
the older form is only available as a build-time configuration option.
If not specially configured,
\fB\%tparm\fP is the same as \fB\%tiparm\fP.
.PP
Both forms of \fB\%tparm\fP have drawbacks:
.bP
Most of the calls to \fB\%tparm\fP use only one or two parameters.
Passing nine on each call is awkward.
.IP
Using
.I long
for the numeric parameter type is a workaround to make the parameter use
the same amount of stack as a pointer.
That approach dates back to the mid-1980s,
before C was standardized.
Since then,
there is a standard
(and pointers are not required to fit in a
.IR long ).
.bP
Providing the right number of parameters for a variadic function
such as \fB\%tiparm\fP can be a problem,
in particular for string parameters.
However,
only a few
.I \%term\%info
capabilities use string parameters
(for instance,
the ones used for programmable function keys).
.IP
The \fI\%ncurses\fP library checks usage of these capabilities,
and returns an error if the capability mishandles string parameters.
But it cannot check if a calling program provides strings in the right
places for the \fB\%tparm\fP calls.
.IP
The \fB\%@TPUT@\fR(1) program checks its use of these capabilities with
a table,
so that it calls \fB\%tparm\fP correctly.
.SS "Special \fITERM\fP treatment"
If configured to use the terminal driver,
.\" XXX: as opposed to the Unix terminal driver, termio(s)?
as with the MinGW port,
.bP
\fB\%setupterm\fP interprets a missing/empty \fITERM\fP variable as the
special value \*(``unknown\*(''.
.IP
SVr4
.I curses
uses the special value \*(``dumb\*(''.
.IP
The difference between the two is that the former uses the
.B \%generic_type
.RB ( gn )
.I \%term\%info
capability,
while the latter does not.
A generic terminal is unsuitable for full-screen applications.
.bP
\fB\%setupterm\fP allows explicit use of the
the windows console driver by checking if \fB$TERM\fP is set to
\*(``#win32con\*('' or an abbreviation of that string.
.SS "Other Portability Issues"
In SVr4,
\fB\%set_curterm\fP returns an
.I int,
.B OK
or
.BR ERR .
We have chosen to implement the X/Open Curses semantics.
.PP
In SVr4,
the third argument of \fB\%tputs\fP has the type
.RB \*(`` "int (*putc)(char)" \*(''.
.PP
At least one implementation of X/Open Curses (Solaris) returns a value
other than
.B OK
or
.B ERR
from \fB\%tputs\fP.
It instead returns the length of the string,
and does no error checking.
.PP
X/Open Curses notes that after calling \fB\%mvcur\fP,
the
.I curses
state may not match the actual terminal state,
and that an application should touch and refresh the window before
resuming normal
.I curses
calls.
Both
.I \%ncurses
and SVr4
.I curses
implement \fB\%mvcur\fP using the
.I SCREEN
data allocated in either \fB\%initscr\fP or \fB\%newterm\fP.
So though it is documented as a
.I \%term\%info
function,
\fB\%mvcur\fP is really a
.I curses
function that is not well specified.
.PP
X/Open notes that after calling \fB\%mvcur\fP,
the
.I curses
state may not match the actual terminal state,
and that an application should touch and refresh the window before
resuming normal
.I curses
calls.
Both
.I \%ncurses
and SVr4
.I curses
implement \fB\%mvcur\fP using the
.I SCREEN
data allocated in either \fB\%initscr\fP or \fB\%newterm\fP.
So though it is documented as a
.I \%term\%info
function,
\fB\%mvcur\fP is really a
.I curses
function that is not well specified.
.PP
X/Open Curses states that the old location must be given for
\fB\%mvcur\fP to accommodate terminals that lack absolute cursor
positioning.
.\" X/Open Curses Issue 7, p. 161
.I \%ncurses
allows the caller to use \-1 for either or both old coordinates.
The \-1 tells
.I \%ncurses
that the old location is unknown,
and that it must use only absolute motion,
as with the
.B \%cursor_address
.RB ( cup )
capability,
rather than the least costly combination of absolute and relative
motion.
.\" ********************************************************************
.SH HISTORY
SVr2 (1984) introduced the
.I \%term\%info
feature.
Its programming manual mentioned the following low-level functions.
.PP
.TS
lB lB
lB lx.
Function        Description
_
fixterm restore terminal to \*(``in \fIcurses\fP\*('' state
gettmode        establish current terminal modes
mvcur   low level cursor motion
putp    use \fBtputs\fP to send characters via \fIputchar\fP
resetterm       set terminal modes to \*(``out of \fIcurses\fP\*(''\
 state
resetty reset terminal flags to stored value
saveterm        save current modes as \*(``in \fIcurses\fP\*('' state
savetty store current terminal flags
setterm establish terminal with given type
setupterm       establish terminal with given type
tparm   interpolate parameters into string capability
tputs   apply padding information to a string
vidattr like \fBvidputs\fP, but output through \fIputchar\fP
vidputs T{
write string to terminal, applying specified attributes
T}
.TE
.PP
The programming manual also mentioned
functions provided for
.I termcap
compatibility
(commenting that they \*(``may go away at a later date\*('').
.PP
.TS
lB lB
lB lx.
Function        Description
_
tgetent look up \fItermcap\fP entry for given \fIname\fP
tgetflag        get Boolean entry for given \fIid\fP
tgetnum get numeric entry for given \fIid\fP
tgetstr get string entry for given \fIid\fP
tgoto   apply parameters to given capability
tputs   T{
write characters via a function parameter, applying padding
T}
.TE
.PP
Early
.I \%term\%info
programs obtained capability values from the
.I \%TERMINAL
structure initialized by \fB\%setupterm\fP.
.PP
SVr3 (1987) extended
.I \%term\%info
by adding functions to retrieve capability values
(like the
.I termcap
interface),
and reusing \fB\%tgoto\fP and \fB\%tputs\fP.
.PP
.TS
lB lB
lB lx.
Function        Description
_
tigetflag       get Boolean entry for given \fIid\fP
tigetnum        get numeric entry for given \fIid\fP
tigetstr        get string entry for given \fIid\fP
.TE
.PP
SVr3 also replaced several of the SVr2
.I \%term\%info
functions that had no counterpart in the
.I termcap
interface,
documenting them as obsolete.
.PP
.TS
lB lB
l  lx.
Function        Replaced by
_
crmode  cbreak
fixterm reset_prog_mode
gettmode        \fIn/a\fP
nocrmode        nocbreak
resetterm       reset_shell_mode
saveterm        def_prog_mode
setterm setupterm
.TE
.PP
SVr3 kept the \fB\%mvcur\fP,
\fB\%vidattr\fP,
and \fB\%vidputs\fP functions,
along with \fB\%putp\fP,
\fB\%tparm\fP,
and \fB\%tputs\fP.
The latter were needed to support padding,
and to handle capabilities accessed by functions such as \fB\%vidattr\fP
(which used more than the two parameters supported by \fB\%tgoto\fP).
.PP
SVr3 introduced the functions for switching between terminal
descriptions;
for example,
\fB\%set_curterm\fP.
Some changes reflected incremental improvements to the SVr2 library.
.bP
The
.I \%TERMINAL
type definition was introduced in SVr3.01,
for the
.I term
structure provided in SVr2.
.bP
Various global variables such as \fB\%boolnames\fP were mentioned
in the programming manual at this point,
though the variables had been provided in SVr2.
.PP
SVr4 (1989) added the \fB\%vid_attr\fP and \fB\%vid_puts\fP functions.
.PP
Other low-level functions are declared in the
.I curses
header files of Unix systems,
but none are documented.
Those noted as \*(``obsolete\*('' by SVr3 remained in use by System\ V's
\fIvi\fP(1) editor.
.SH SEE ALSO
\fB\%curses\fP(3X),
\fB\%curs_initscr\fP(3X),
\fB\%curs_kernel\fP(3X),
\fB\%curs_memleaks\fP(3X),
\fB\%curs_termcap\fP(3X),
\fB\%curs_variables\fP(3X),
\fB\%putc\fP(3),
\fB\%term_variables\fP(3X),
\fB\%terminfo\fP(5)