- 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., libncurs-
- es_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 cursestrace routines are used for debugging the ncurses libraries,
+ as well as applications which use the ncurses libraries. Some
+ limitations apply:
+
+ o Aside from curses_trace, the other functions are normally available
+ only with the debugging library e.g., libncurses_g.a.
+
+ All of the trace functions may be compiled into any model (shared,
+ static, profile) by defining the symbol TRACE.
+
+ o Additionally, the functions which use cchar_t are only available
+ with the wide-character configuration of the libraries.
The principal parts of this interface are
- otrace, which selectively enables different tracing features, and
+ ocurses_trace, which selectively enables different tracing features,
+ and
o_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.
+
+ The curses_trace function is always available, whether or not the other
+ trace functions are available:
+
+ o If tracing is available, calling curses_trace with a nonzero
+ parameter updates the trace mask, and returns the previous trace
+ mask.
- 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 func-
- tion, some use a buffer-number parameter, telling the library to allo-
- cate additional string-areas.
+ When the trace mask is nonzero, ncurses creates the file "trace" in
+ the current directory for output. If the file already exists, no
+ tracing is done.
+
+ o If tracing is not available, curses_trace returns zero (0).
@@ -107,9 +127,9 @@
TRACE_DISABLE
turn off tracing by passing a zero parameter.
- The library flushes the output file, but retains an open file-de-
- scriptor to the trace file so that it can resume tracing later if
- a nonzero parameter is passed to the trace function.
+ 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 curses_trace function.
TRACE_TIMES
trace user and system times of updates.
@@ -158,60 +178,90 @@
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
+ Some tracing features are enabled whenever the curses_trace parameter
+ is 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 was called:
-
- 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 and trace) use the same variable (_nc_tracing), which
- determines the messages which are written.
+ The command-line utilities such as tic(1) provide a verbose option
+ which extends the set of messages written using the curses_trace
+ function. Both of these (-v and curses_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 debug-
- ging output may be directed to the trace file if the NCURSES_TRACE en-
- vironment variable is set:
+ 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:
o messages produced in the utility are written to the standard error.
o messages produced by the underlying library are written to trace.
- If ncurses is built without tracing, none of the latter are produced,
+ 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
+ Routines which return a value are designed to be used as parameters to
the _tracef routine.
+
+ A positive integral value stored in this variable causes the following
+ functions to enable the tracing feature as if curses_trace were called.
+
+ filter, initscr, new_prescr, newterm, nofilter, restartterm,
+ ripoffline, setupterm, slk_init, tgetent, use_env,
+ use_extended_names, use_tioctl
+
+
- 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.
+ These functions are not part of the X/Open Curses interface. Some
+ other curses implementations are known to have similar features, but
+ they are not compatible with ncurses:
+
+ o SVr4 provided traceon and traceoff, to control whether debugging
+ information was written to the "trace" file. While the functions
+ were always available, this feature was only enabled if DEBUG was
+ defined when building the library.
+
+ The SVr4 tracing feature is undocumented.
+
+ o PDCurses provides traceon and traceoff, which (like SVr4) are
+ always available, and enable tracing to the "trace" file only when
+ a debug-library is built.
+
+ PDCurses has a short description of these functions, with a note
+ that they are not present in X/Open Curses, ncurses or NetBSD. It
+ does not mention SVr4, but the functions' inclusion in a header
+ file section labeled "Quasi-standard" hints at the origin.
- A few functions are not provided when symbol versioning is used:
+ o NetBSD does not provide functions for enabling/disabling traces.
+ It uses environment variables CURSES_TRACE_MASK and
+ CURSES_TRACE_FILE to determine what is traced, and where the
+ results are written. This is available only when a debug-library
+ is built.
+
+ The NetBSD tracing feature is undocumented.
+
+ A few ncurses functions are not provided when symbol versioning is
+ used:
_nc_tracebits, _tracedump, _tracemouse
+ The original trace routine was deprecated because it often conflicted
+ with application names.
+