/* * TraceOut(fmt, ...) * * outputs a formatted string a a trace file for debugging. * The file 'trace.txt' is opened on the first call and re-used when called again. * output is: "YYYY-MM-DD HH.MM.SS (format)\n". */void trace_out(const char *fmt, ... ) {// our static file handler static FILE *trace_file = 0L;// create a data/time stamp "YYYY-MM-DD HH.MM.SS" into date_string time_t now = time(0L); char date_string[23]; strftime(date_string, 256, "%Y-%m-%d %H.%M.%S", localtime(&now));// check the file has been opened if (!trace_file) { // attempt to open the trace file trace_file = fopen("trace.txt", "a+"); if (!trace_file) return; // hmmm, cant open the file, guess we can trace out }// create a variable list for the unknown passed parameters va_list v; va_start(v, fmt);// write out a line to the trace file {date/time} |{format_line}\n fprintf(trace_file, "%s |", date_string); vfprintf(trace_file, fmt, v); fputc('\n', trace_file); fflush(trace_file);}