File System Operations (cont)
int open(char * Path, int Flags)
int open(char * Path, int Flags, mode_t mode)
- attempt to open an object at Path, according to Flags
- flags (defined in
<fcntl.h> )
-
O_RDONLY ... open object for reading
-
O_WRONLY ... open object for writing
-
O_APPEND ... append on each write
-
O_RDWR ... open object for reading and writing
-
O_CREAT ... create object if doesn't exist
-
O_TRUNC ... truncate to size 0
- flags can be combined e.g.
(O_WRONLY|O_CREAT)
- if successful, return file descriptor (small +ve
int )
- if unsuccessful, return -1 and set
errno
You should always use the open command that allows you to specify the mode (file permissions) if you are creating a file. Otherwise you will get weird garbage permissions on your newly created files.
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