FD(4)		    UNIX Programmer's Manual		    FD(4)



NAME
     fd, stdin, stdout, stderr file descriptor files

DESCRIPTION
     The files /_d_e_v/_f_d/_0 through /_d_e_v/_f_d/# refer to file descrip-
     tors which can be accessed through the file system.  If the
     file descriptor is open and the mode the file is being
     opened with is a subset of the mode of the existing descrip-
     tor, the call:

	  fd = open("/dev/fd/0", mode);

     and the call:

	  fd = fcntl(0, F_DUPFD, 0);

     are equivalent.

     Opening the files /_d_e_v/_s_t_d_i_n, /_d_e_v/_s_t_d_o_u_t and /_d_e_v/_s_t_d_e_r_r is
     equivalent to the following calls:

	  fd = fcntl(STDIN_FILENO,  F_DUPFD, 0);
	  fd = fcntl(STDOUT_FILENO, F_DUPFD, 0);
	  fd = fcntl(STDERR_FILENO, F_DUPFD, 0);

     Flags to the open(2) call other than O_RDONLY, O_WRONLY and
     O_RDWR are ignored.

FILES
     /dev/fd/#
     /dev/stdin
     /dev/stdout
     /dev/stderr

SEE ALSO
     tty(4)



















Printed 11/26/99	February 4, 1997			1