isatty - test whether a file descriptor refers to a terminal

       For an explanation of the terms used in this section, see attributes(7).
       ┌─────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                                                                   │ Attribute     │ Value   │
       ├─────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │ isatty()                                                                    │ Thread safety │ MT-Safe │
       └─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

       The isatty() function tests whether fd is an open file descriptor referring to a terminal.

EBADFfd is not a valid file descriptor.

       ENOTTYfd refers to a file other than a terminal.  On some older kernels, some types of files resulted in
              the error EINVAL in this case (which is a violation of POSIX, which specifies the error ENOTTY).

       POSIX.1-2001, SVr4, 4.3BSD.

       Standard C library (libc, -lc)

       isatty - test whether a file descriptor refers to a terminal

isatty() returns 1 if fd is an open file descriptor referring to a terminal; otherwise 0 is returned, and
       errno is set to indicate the error.

fstat(2), ttyname(3)

Linux man-pages 6.9.1                              2024-05-02                                          isatty(3)

       POSIX.1-2008.

#include<unistd.h>intisatty(intfd);