🚀 go-pugleaf

jwbirdsa@amc.com (James Birdsall) writes:

>In article <1991Apr16.145847.20316@midway.uchicago.edu> valley@gsbsun.uchicago.edu (Doug Dougherty) writes:
>>collinsa@p4.cs.man.ac.uk (Adrian Collins) writes:
>>>Does anybody know how to sense whether output redirection has been used
>>>on the command line?
>>isatty(1)
>>(Works in Turbo C)

>   Well, almost. isatty() returns true if the supplied handle is the
>console *or* a printer or serial port. Determining whether the handle is
>actually the console or not requires an ioctl() and checking some bits.

Someone else pointed this out to me in email as well.  Yes, this is only
a 90% solution.  Actually, I think, in DOS, isatty() returns true iff
the handle refers to a *character device* (my emphasis).  Which includes
of course, not only CON, COMx, PRN, but also NUL as well as any installed
character devices.

Still, I think it handles most of the occurrences, since what most users
are concerned about is redirection to a file anyway.  And the original
poster did refer to TurboC specifically, and isatty() does have the
virtue of being a regular TC built-in function.

--

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