Detect if stdout is redirected to a pipe (not to a file, character device, terminal, or socket)?

Question

Ideally, this would be scriptable in shell, but Perl or Python would be fine. C code could be helpful, but probably fails cost/benefit.

I recognize that redirection to a

Answer 1

In Python:

import sys
print sys.stdout.isatty()

Examples:

$ ./a
True
$ ./a | less
False