fopen与open的不同

NAME
       open - open a file

SYNOPSIS
        #include <sys/stat.h>
        #include <fcntl.h>
        int open(const char *path, int oflag, ...  );
DESCRIPTION
       The  open() function shall establish the connection between a file and a file descriptor. It shall  create  an  open  file  description  that refers  to  a file and a file descriptor that refers to that open file description. The file descriptor is used by  other  I/O  functions  to refer  to that file. The path argument points to a pathname naming the file.

FILE *fopen(const char *filename, const char *mode)

fopen opens the named file, and returns a stream, or NULL if the attempt fails. Legal values for mode include:

    "r" open text file for reading 
    "w" create text file for writing; discard previous contents if any 
    "a" append; open or create text file for writing at end of file 
    "r+" open text file for update (i.e., reading and writing) 
    "w+" create text file for update, discard previous contents if any 
    "a+" append; open or create text file for update, writing at end  
    Update mode permits reading and writing the same file; fflush or a file-positioning function must be called between a read and a write or vice versa. If the mode includes b after the initial letter, as in "rb" or "w+b", that indicates a binary file. Filenames are limited to FILENAME_MAX characters. At most FOPEN_MAX files may be open at once.