Concat多个字符串？

Question

我有一个类似下面的一行,但我需要连接目录的斜杠,有没有办法安全地连接多个字符串？

// Need to include \\ after windowsDir
FILE *dest = fopen(strcat(windowsDir, filename),"wb");

Answer 1

char *buf = malloc(strlen(windowsDir) + 1 + strlen(filename) + 1); // len + \ + len + \0
sprintf(buf, "%s\\%s", windowsDir, filename);
FILE *dest = fopen(buf, "wb");
free(buf);