NAME

       trace, _tracef, _traceattr, _traceattr2, _tracecchar_t, _tracecchar_t2, _tracechar,
       _tracechtype, _tracechtype2, _nc_tracebits, _tracedump, _tracemouse - curses debugging
       routines

SYNOPSIS

       #include <curses.h>

       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 *string);
       char *_tracechar(int ch);
       char *_tracechtype(chtype ch);
       char *_tracechtype2(int buffer, chtype ch);

       void _tracedump(const char *label, WINDOW *win);
       char *_nc_tracebits(void);
       char *_tracemouse(const MEVENT *event);

DESCRIPTION

       The  trace  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 TRACE.   Additionally,  some  functions  are  only
       available with the wide-character configuration of the libraries.

   Functions
       The principal parts of this interface are

       •   trace, which selectively enables different tracing features, and

       •   _tracef, which writes formatted data to the trace file.

       Calling trace with a nonzero parameter creates the file trace in the current directory for
       output.  If the file already exists, no tracing is done.

       The  other  functions  either  return  a  pointer  to  a  string-area  (allocated  by  the
       corresponding  function),  or  return  no  value (such as _tracedump, which 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 string-areas.

   Trace Parameter
       The  trace  parameter is formed by OR'ing values from the list of TRACE_xxx definitions in
       <curses.h>.  These include:

       TRACE_DISABLE
            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_TIMES
            trace user and system times of updates.

       TRACE_TPUTS
            trace tputs(3X) calls.

       TRACE_UPDATE
            trace update actions, old & new screens.

       TRACE_MOVE
            trace cursor movement and scrolling.

       TRACE_CHARPUT
            trace all character outputs.

       TRACE_ORDINARY
            trace all update actions.  The old and new screen contents are written to  the  trace
            file for each refresh.

       TRACE_CALLS
            trace  all  curses calls.  The parameters for each call are traced, as well as return
            values.

       TRACE_VIRTPUT
            trace virtual character puts, i.e., calls to addch.

       TRACE_IEVENT
            trace low-level input processing, including timeouts.

       TRACE_BITS
            trace state of TTY control bits.

       TRACE_ICALLS
            trace internal/nested calls.

       TRACE_CCALLS
            trace per-character calls.

       TRACE_DATABASE
            trace read/write of terminfo/termcap data.

       TRACE_ATTRS
            trace changes to video attributes and colors.

       TRACE_MAXIMUM
            maximum trace level, enables all of the separate trace features.

       Some tracing features are enabled whenever the trace parameter is nonzero.  Some  features
       overlap.  The specific names are used as a guideline.

   Initialization
       These  functions  check the NCURSES_TRACE environment variable, to set the tracing feature
       as if trace was called:

           filter, initscr, new_prescr, newterm, nofilter, restartterm, ripoffline, setupterm,
           slk_init, tgetent, use_env, use_extended_names, use_tioctl

   Command-line Utilities
       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 and trace) use  the  same
       variable (_nc_tracing), which determines the messages which are written.

       Because  the  command-line  utilities may call initialization functions such as setupterm,
       tgetent or use_extended_names, some of their debugging output may be directed to the trace
       file if the NCURSES_TRACE environment variable is set:

       •   messages produced in the utility are written to the standard error.

       •   messages produced by the underlying library are written to trace.

       If  ncurses  is  built  without  tracing,  none  of  the  latter  are  produced, and fewer
       diagnostics are provided by the command-line utilities.

RETURN VALUE

       Routines which return a value are designed  to  be  used  as  parameters  to  the  _tracef
       routine.

PORTABILITY

       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

SEE ALSO

       ncurses(3NCURSES).

                                                                                  trace(3NCURSES)