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@(#)open.2 4.1 (Berkeley) 05/09/85

C 4 open - open for reading or writing

 open(name, mode)  char *name; 

Open opens the file name for reading (if mode is 0), writing (if mode is 1) or for both reading and writing (if mode is 2). Name is the address of a string of ASCII characters representing a path name, terminated by a null character.

The file is positioned at the beginning (byte 0). The returned file descriptor must be used for subsequent calls for other input-output functions on the file.

creat(2), read(2), write(2), dup(2), close(2) The value -1 is returned if the file does not exist, if one of the necessary directories does not exist or is unreadable, if the file is not readable (resp. writable), or if too many files are open. (open = 5.)

sys open; name; mode

(file descriptor in r0)

It should be possible to optionally open files for writing with exclusive use, and to optionally call open without the possibility of hanging waiting for carrier on communication lines.