The functions described in this chapter only work on files that
correspond to terminal devices. You can find out whether a file
descriptor is associated with a terminal by using the isatty
function.
Prototypes for the functions in this section are declared in the header file `unistd.h'.
1
if filedes is a file descriptor
associated with an open terminal device, and @math{0} otherwise.
If a file descriptor is associated with a terminal, you can get its
associated file name using the ttyname
function. See also the
ctermid
function, described in section Identifying the Controlling Terminal.
ttyname
function returns a pointer to a
statically-allocated, null-terminated string containing the file name of
the terminal file. The value is a null pointer if the file descriptor
isn't associated with a terminal, or the file name cannot be determined.
ttyname_r
function is similar to the ttyname
function
except that it places its result into the user-specified buffer starting
at buf with length len.
The normal return value from ttyname_r
is @math{0}. Otherwise an
error number is returned to indicate the error. The following
errno
error conditions are defined for this function:
EBADF
ENOTTY
ERANGE
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