The filter routine, if used, must be called before initscr or newterm
- are called. The effect is that, during those calls, LINES is set to 1;
- the capabilities clear, cup, cud, cud1, cuu1, cuu, vpa are disabled;
- and the home string is set to the value of cr.
+ are called. Calling filter causes these changes in initialization:
- The nofilter routine cancels the effect of a preceding filter call.
- That allows the caller to initialize a screen on a different device,
- using a different value of $TERM. The limitation arises because the
+ oLINES is set to 1;
+
+ o the capabilities clear, cud1, cud, cup, cuu1, cuu, vpa are dis-
+ abled;
+
+ o the capability ed is disabled if bce is set;
+
+ o and the home string is set to the value of cr.
+
+ The nofilter routine cancels the effect of a preceding filter call.
+ That allows the caller to initialize a screen on a different device,
+ using a different value of $TERM. The limitation arises because the
filter routine modifies the in-memory copy of the terminal information.
- The use_env routine, if used, should be called before initscr or
- newterm are called (because those compute the screen size). It modi-
- fies the way ncurses treats environment variables when determining the
+ The use_env routine, if used, should be called before initscr or
+ newterm are called (because those compute the screen size). It modi-
+ fies the way ncurses treats environment variables when determining the
screen size.
- o Normally ncurses looks first at the terminal database for the
+ o Normally ncurses looks first at the terminal database for the
screen size.
- If use_env was called with FALSE for parameter, it stops here un-
- less If use_tioctl was also called with TRUE for parameter.
+ If use_env was called with FALSE for parameter, it stops here un-
+ less use_tioctl was also called with TRUE for parameter.
- o Then it asks for the screen size via operating system calls. If
+ o Then it asks for the screen size via operating system calls. If
successful, it overrides the values from the terminal database.
- o Finally (unless use_env was called with FALSE parameter), ncurses
- examines the LINES or COLUMNS environment variables, using a value
- in those to override the results from the operating system or ter-
+ o Finally (unless use_env was called with FALSE parameter), ncurses
+ examines the LINES or COLUMNS environment variables, using a value
+ in those to override the results from the operating system or ter-
minal database.
- Ncurses also updates the screen size in response to SIGWINCH, un-
+ Ncurses also updates the screen size in response to SIGWINCH, un-
less overridden by the LINES or COLUMNS environment variables,
- The use_tioctl routine, if used, should be called before initscr or
- newterm are called (because those compute the screen size). After
- use_tioctl is called with TRUE as an argument, ncurses modifies the
+ The use_tioctl routine, if used, should be called before initscr or
+ newterm are called (because those compute the screen size). After
+ use_tioctl is called with TRUE as an argument, ncurses modifies the
last step in its computation of screen size as follows:
- o checks if the LINES and COLUMNS environment variables are set to a
+ o checks if the LINES and COLUMNS environment variables are set to a
number greater than zero.
- o for each, ncurses updates the corresponding environment variable
- with the value that it has obtained via operating system call or
+ o for each, ncurses updates the corresponding environment variable
+ with the value that it has obtained via operating system call or
from the terminal database.
- oncurses re-fetches the value of the environment variables so that
+ oncurses re-fetches the value of the environment variables so that
it is still the environment variables which set the screen size.
The use_env and use_tioctl routines combine as summarized here:
use_envuse_tioctlSummary
----------------------------------------------------------------
- TRUE FALSE This is the default behavior. ncurses
+ TRUE FALSE This is the default behavior. ncurses
uses operating system calls unless over-
ridden by $LINES or $COLUMNS environment
variables.
- TRUE TRUE ncurses updates $LINES and $COLUMNS
+ TRUE TRUE ncurses updates $LINES and $COLUMNS
based on operating system calls.
FALSE TRUE ncurses ignores $LINES and $COLUMNS, us-
es operating system calls to obtain
size.
- FALSE FALSE ncurses relies on the terminal database
+ FALSE FALSE ncurses relies on the terminal database
to determine size.
- The putwin routine writes all data associated with window (or pad) win
+ The putwin routine writes all data associated with window (or pad) win
into the file to which filep points. This information can be later re-
trieved using the getwin function.
- The getwin routine reads window related data stored in the file by
- putwin. The routine then creates and initializes a new window using
- that data. It returns a pointer to the new window. There are a few
+ The getwin routine reads window related data stored in the file by
+ putwin. The routine then creates and initializes a new window using
+ that data. It returns a pointer to the new window. There are a few
caveats:
o the data written is a copy of the WINDOW structure, and its associ-
- ated character cells. The format differs between the wide-charac-
- ter (ncursesw) and non-wide (ncurses) libraries. You can transfer
+ ated character cells. The format differs between the wide-charac-
+ ter (ncursesw) and non-wide (ncurses) libraries. You can transfer
data between the two, however.
- o the retrieved window is always created as a top-level window (or
+ o the retrieved window is always created as a top-level window (or
pad), rather than a subwindow.
- o the window's character cells contain the color pair value, but not
- the actual color numbers. If cells in the retrieved window use
- color pairs which have not been created in the application using
+ o the window's character cells contain the color pair value, but not
+ the actual color numbers. If cells in the retrieved window use
+ color pairs which have not been created in the application using
init_pair, they will not be colored when the window is refreshed.
- The delay_output routine inserts an ms millisecond pause in output.
- This routine should not be used extensively because padding characters
- are used rather than a CPU pause. If no padding character is speci-
+ The delay_output routine inserts an ms millisecond pause in output.
+ This routine should not be used extensively because padding characters
+ are used rather than a CPU pause. If no padding character is speci-
fied, this uses napms to perform the delay.
- The flushinp routine throws away any typeahead that has been typed by
+ The flushinp routine throws away any typeahead that has been typed by
the user and has not yet been read by the program.
- Except for flushinp, routines that return an integer return ERR upon
- failure and OK (SVr4 specifies only "an integer value other than ERR")
+ Except for flushinp, routines that return an integer return ERR upon
+ failure and OK (SVr4 specifies only "an integer value other than ERR")
upon successful completion.
Routines that return pointers return NULL on error.
@@ -226,77 +234,77 @@
returns an error if the terminal was not initialized.
putwin
- returns an error if the associated fwrite calls return an er-
+ returns an error if the associated fwrite calls return an er-
ror.
- The SVr4 documentation describes the action of filter only in the
- vaguest terms. The description here is adapted from the XSI Curses
+ The SVr4 documentation describes the action of filter only in the
+ vaguest terms. The description here is adapted from the XSI Curses
standard (which erroneously fails to describe the disabling of cuu).
- The keyname function may return the names of user-defined string capa-
- bilities which are defined in the terminfo entry via the -x option of
+ The keyname function may return the names of user-defined string capa-
+ bilities which are defined in the terminfo entry via the -x option of
tic. This implementation automatically assigns at run-time keycodes to
- user-defined strings which begin with "k". The keycodes start at
+ 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 use_extended_names(3x) function controls
- whether this data is loaded when the terminal description is read by
+ because user-defined codes are merged from all terminal descriptions
+ which have been loaded. The use_extended_names(3x) function controls
+ whether this data is loaded when the terminal description is read by
the library.
- The nofilter and use_tioctl routines are specific to ncurses. They
- were not supported on Version 7, BSD or System V implementations. It
- is recommended that any code depending on ncurses extensions be condi-
+ The nofilter and use_tioctl routines are specific to ncurses. They
+ were not supported on Version 7, BSD or System V implementations. It
+ is recommended that any code depending on ncurses extensions be condi-
tioned using NCURSES_VERSION.
The putwin and getwin functions have several issues with portability:
- o The files written and read by these functions use an implementa-
+ o The files written and read by these functions use an implementa-
tion-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 scr_init, etc.) originated with
+ Interestingly enough, according to the copyright dates in Solaris
+ source, the functions (along with scr_init, etc.) originated with
the University of California, Berkeley (in 1982) and were later (in
- 1988) incorporated into SVr4. Oddly, there are no such functions
+ 1988) incorporated into SVr4. Oddly, there are no such functions
in the 4.3BSD curses sources.
o Most implementations simply dump the binary WINDOW structure to the
- file. These include SVr4 curses, NetBSD and PDCurses, as well as
+ file. These include SVr4 curses, NetBSD and PDCurses, as well as
older ncurses 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
- fwrite and fread functions). Those that use textual dumps use
+ The implementations which use binary dumps use block-I/O (the
+ fwrite and fread 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
+ 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.
- The XSI Curses standard, Issue 4 describes these functions. It states
+ The XSI Curses standard, Issue 4 describes these functions. It states
that unctrl and wunctrl will return a null pointer if unsuccessful, but
- does not define any error conditions. This implementation checks for
+ does not define any error conditions. This implementation checks for
three cases:
- o the parameter is a 7-bit US-ASCII code. This is the case that
+ o the parameter is a 7-bit US-ASCII code. This is the case that
X/Open Curses documented.
o the parameter is in the range 128-159, i.e., a C1 control code. If
- use_legacy_coding has been called with a 2 parameter, unctrl re-
- turns the parameter, i.e., a one-character string with the parame-
- ter as the first character. Otherwise, it returns "~@", "~A",
+ use_legacy_coding has been called with a 2 parameter, unctrl re-
+ turns the parameter, i.e., a one-character string with the parame-
+ ter as the first character. Otherwise, it returns "~@", "~A",
etc., analogous to "^@", "^A", C0 controls.
X/Open Curses does not document whether unctrl can be called before
@@ -307,28 +315,32 @@
pointer.
The strings returned by unctrl 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 conven-
+ compile time, showing C1 controls from the upper-128 codes with a "~"
+ prefix rather than "^". Other implementations have different conven-
tions. 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
- use_legacy_coding function allows the caller to change the output of
+ uses 8 bits but does not modify the string to reflect locale. The
+ use_legacy_coding function allows the caller to change the output of
unctrl.
- Likewise, the meta(3x) function allows the caller to change the output
- of keyname, i.e., it determines whether to use the "M-" prefix for
- "meta" keys (codes in the range 128 to 255). Both use_legacy_coding
- and meta 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 keyname is called before initializing curses), this
+ Likewise, the meta(3x) function allows the caller to change the output
+ of keyname, i.e., it determines whether to use the "M-" prefix for
+ "meta" keys (codes in the range 128 to 255). Both use_legacy_coding
+ and meta 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 keyname is called before initializing curses), this
implementation returns strings "M-^@", "M-^A", etc.
+ X/Open Curses documents unctrl as declared in <unctrl.h>, which ncurses
+ does. However, ncurses' <curses.h> includes <unctrl.h>, matching the
+ behavior of SVr4 curses. Other implementations may not do that.
+
- If ncurses is configured to provide the sp-functions extension, the
- state of use_env and use_tioctl may be updated before creating each
- screen rather than once only (curs_sp_funcs(3x)). This feature of
+ If ncurses is configured to provide the sp-functions extension, the
+ state of use_env and use_tioctl may be updated before creating each
+ screen rather than once only (curs_sp_funcs(3x)). This feature of
use_env is not provided by other implementation of curses.