More likely still, some part of the C library is doing a terminal-related ioctl() system call on one of the standard filehandles like STDIN, finding that its not in fact a terminal (e.g. because STDIN hs been redirected) and safely ignoring the harmless error. I.e. the C library logic is along the lines of "if this file handle is a terminal do some extra initialisation, otherwise don't worry about it".

I used to see this on Solaris all the time when doing a truss(1); I don't see it on linux though.

Dave.