1.
#include <stdio.h>
FILE *logfile = fopen("log.txt", "w");
#define _LogPrint(fmt, ...) if(logfile){fprintf(logfile, fmt, ##__VA_ARGS__); fflush(logfile); }
2.
#include <stdio.h>
FILE *logfile = fopen("log.txt", "w");
CHAR buf[256];
#define _LogPrint(fmt, ...) /
sprintf(buf, fmt, ##__VA_ARGS__); /
fwrite(buf, 1, strlen(buf), logfile); /
fflush(logfile);