diff -r 5314ebdcb38d -r 2d43f05b284c pdcurses/debug.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pdcurses/debug.c	Thu Jul 23 18:07:39 2015 +0300
@@ -0,0 +1,81 @@
+/* Public Domain Curses */
+
+#include <curspriv.h>
+
+RCSID("$Id: debug.c,v 1.7 2008/07/13 16:08:18 wmcbrine Exp $")
+
+/*man-start**************************************************************
+
+  Name:                                                         debug
+
+  Synopsis:
+        void traceon(void);
+        void traceoff(void);
+        void PDC_debug(const char *, ...);
+
+  Description:
+        traceon() and traceoff() toggle the recording of debugging 
+        information to the file "trace". Although not standard, similar 
+        functions are in some other curses implementations.
+
+        PDC_debug() is the function that writes to the file, based on 
+        whether traceon() has been called. It's used from the PDC_LOG() 
+        macro.
+
+  Portability                                X/Open    BSD    SYS V
+        traceon                                 -       -       -
+        traceoff                                -       -       -
+        PDC_debug                               -       -       -
+
+**man-end****************************************************************/
+
+#include <string.h>
+#include <sys/types.h>
+#include <time.h>
+
+bool pdc_trace_on = FALSE;
+
+void PDC_debug(const char *fmt, ...)
+{
+    va_list args;
+    FILE *dbfp;
+    char hms[9];
+    time_t now;
+
+    if (!pdc_trace_on)
+        return; 
+
+    /* open debug log file append */
+
+    dbfp = fopen("trace", "a");
+    if (!dbfp)
+    {
+        fprintf(stderr,
+            "PDC_debug(): Unable to open debug log file\n");
+        return;
+    }
+
+    time(&now);
+    strftime(hms, 9, "%H:%M:%S", localtime(&now));
+    fprintf(dbfp, "At: %8.8ld - %s ", (long) clock(), hms);
+
+    va_start(args, fmt);
+    vfprintf(dbfp, fmt, args);
+    va_end(args);
+
+    fclose(dbfp);
+}
+
+void traceon(void)
+{
+    PDC_LOG(("traceon() - called\n"));
+
+    pdc_trace_on = TRUE;
+}
+
+void traceoff(void)
+{
+    PDC_LOG(("traceoff() - called\n"));
+
+    pdc_trace_on = FALSE;
+}