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isatty(3)


NAME

   isatty - test whether a file descriptor refers to a terminal

SYNOPSIS

   #include <unistd.h>

   int isatty(int fd);

DESCRIPTION

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

RETURN VALUE

   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.

ERRORS

   EBADF  fd is not a valid file descriptor.

   EINVAL fd refers to a file other than a  terminal.   POSIX.1  specifies
          the error ENOTTY for this case.

ATTRIBUTES

   For   an   explanation   of   the  terms  used  in  this  section,  see
   attributes(7).

   
   Interface  Attribute      Value   
   
   isatty()   Thread safety  MT-Safe

CONFORMING TO

   POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.

SEE ALSO

   fstat(2), ttyname(3)

COLOPHON

   This page is part of release 4.09 of the Linux  man-pages  project.   A
   description  of  the project, information about reporting bugs, and the
   latest    version    of    this    page,    can     be     found     at
   https://www.kernel.org/doc/man-pages/.



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