#include <stdarg.h> FILE* pLogFile = NULL; #define LOG_FILE "log.txt" void log(char *fmt, ...) { if(!pLogFile) pLogFile = fopen(LOG_FILE, "w"); va_list ap ; va_start(ap, fmt) ; vfprintf(pLogFile, fmt, ap) ; fprintf(pLogFile, "\n"); fflush(pLogFile); va_end(ap); }