1ISATTY(3)                  Linux Programmer's Manual                 ISATTY(3)
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NAME

6       isatty - test whether a file descriptor refers to a terminal
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SYNOPSIS

9       #include <unistd.h>
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11       int isatty(int fd);
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DESCRIPTION

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

18       isatty() returns 1 if fd is an open file descriptor referring to a ter‐
19       minal; otherwise 0 is returned, and errno is set to indicate the error.
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ERRORS

22       EBADF  fd is not a valid file descriptor.
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24       EINVAL fd  refers to a file other than a terminal.  POSIX.1-2001 speci‐
25              fies the error ENOTTY for this case.
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CONFORMING TO

28       SVr4, 4.3BSD, POSIX.1-2001.
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SEE ALSO

31       fstat(2), ttyname(3)
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COLOPHON

34       This page is part of release 3.25 of the Linux  man-pages  project.   A
35       description  of  the project, and information about reporting bugs, can
36       be found at http://www.kernel.org/doc/man-pages/.
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40Linux                             2008-12-03                         ISATTY(3)
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