curs_trace(3X)

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

SYNOPSIS
#include <curses.h>

void _tracef(const char *format, ...);
void _tracedump(const char *label, WINDOW *win);
char *_traceattr(attr_t attr);
char *_traceattr2(int buffer, chtype ch);
char *_nc_tracebits(void);
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);
char *_tracemouse(const MEVENT *event);
void trace(const unsigned int param);

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.

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 opens the file trace in the current directory for output. The parameter is formed by OR'ing values from the list of TRACE_xxx definitions in <curses.h>. These include:

TRACE_DISABLE
    turn off tracing.

TRACE_TIMES
    trace user and system times of updates.

TRACE_TPUTS
    trace tputs 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.

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.

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

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.

SEE ALSO
curses(3X).