Write simultaneousely to two streams

Question

Is there a way to to couple two streams (or file descriptors) together so that writing to one stream will also write to the second one? (C, Linux)

Thanks.

Answer 1

The first thing that came to mind to me was also "tee". So, let's combine C and the shell with popen:

FILE * multi_out;

multi_out = popen( "tee file1.out > file2.out", "w");
/* error checks, actual work here */
pclose( multi_out);
/* error checks here */

As a Unix bigot, I have assumed you are not trying this on Windows.