시스템소프트웨어 질문입니다.

#include <fcntl.h>
...
int fd;
mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
char *filename = "/tmp/file";
...
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, mode);

              S_IRWXU  00700 user (file owner) has read, write, and execute
                       permission
 
              S_IRUSR  00400 user has read permission
 
              S_IWUSR  00200 user has write permission
 
              S_IXUSR  00100 user has execute permission
 
              S_IRWXG  00070 group has read, write, and execute permission
 
              S_IRGRP  00040 group has read permission
 
              S_IWGRP  00020 group has write permission
 
              S_IXGRP  00010 group has execute permission
 
              S_IRWXO  00007 others have read, write, and execute permission
 
              S_IROTH  00004 others have read permission
 
              S_IWOTH  00002 others have write permission
 
              S_IXOTH  00001 others have execute permission