void trace(const unsigned int param);
void _tracef(const char *format, ...);
char *_traceattr(attr_t attr);
char *_traceattr2(int buffer, chtype ch);
char *_tracecchar_t(const cchar_t *string);
char *_tracecchar_t2(int buffer, const cchar_t
char *_tracechar(int ch);
char *_tracechtype(chtype ch);
char *_tracechtype2(int buffer, chtype ch);
void _tracedump(const char *label, WINDOW
char *_tracemouse(const MEVENT *event);
routines are used for debugging the ncurses libraries, as well
as applications which use the ncurses libraries. These functions are normally
available only with the debugging library e.g., libncurses_g.a
, but may
be compiled into any model (shared, static, profile) by defining the symbol
. Additionally, some functions are only available with the
wide-character configuration of the libraries.
The principal parts of this interface are
- trace, which selectively enables different tracing
- _tracef, which writes formatted data to the
with a nonzero parameter creates the file trace
the current directory for output. If the file already exists, no tracing is
The other functions either return a pointer to a string-area (allocated by the
corresponding function), or return no value (such as _tracedump
implements the screen dump for TRACE_UPDATE
). The caller should not
free these strings, since the allocation is reused on successive calls. To
work around the problem of a single string-area per function, some use a
buffer-number parameter, telling the library to allocate additional
The trace parameter is formed by OR'ing values from the list of
definitions in <curses.h>
. These include:
- turn off tracing by passing a zero parameter.
- The library flushes the output file, but retains an open
file-descriptor to the trace file so that it can resume tracing later if a
nonzero parameter is passed to the trace function.
- trace user and system times of updates.
- trace tputs(3X) calls.
- trace update actions, old & new screens.
- trace cursor movement and scrolling.
- trace all character outputs.
- trace all update actions. The old and new screen contents
are written to the trace file for each refresh.
- trace all curses calls. The parameters for each call are
traced, as well as return values.
- trace virtual character puts, i.e., calls to
- trace low-level input processing, including timeouts.
- trace state of TTY control bits.
- trace internal/nested calls.
- trace per-character calls.
- trace read/write of terminfo/termcap data.
- trace changes to video attributes and colors.
- maximum trace level, enables all of the separate trace
Some tracing features are enabled whenever the trace
nonzero. Some features overlap. The specific names are used as a guideline.
These functions check the NCURSES_TRACE
environment variable, to set the
tracing feature as if trace
filter, initscr, new_prescr, newterm, nofilter, restartterm, ripoffline,
setupterm, slk_init, tgetent, use_env, use_extended_names, use_tioctl
The command-line utilities such as tic
(1) provide a verbose option which
extends the set of messages written using the trace
function. Both of
these ( -v
) use the same variable (
), which determines the messages which are written.
Because the command-line utilities may call initialization functions such as
, some of their
debugging output may be directed to the trace
file if the
environment variable is set:
- messages produced in the utility are written to the
- messages produced by the underlying library are written to
If ncurses is built without tracing, none of the latter are produced, and fewer
diagnostics are provided by the command-line utilities.
Routines which return a value are designed to be used as parameters to the
These functions are not part of the XSI interface. Some other curses
implementations are known to have similar, undocumented features, but they are
not compatible with ncurses.
A few functions are not provided when symbol versioning is used:
_nc_tracebits, _tracedump, _tracemouse