c - Writing to both stdout & a file

Question

I have a parent process which forks out a child to perform execv().

I need the output given by execv() to stdout to be displayed onscreen as also copied to a log file.

How do I write the same output to both stdout & a file, without using pipes or tees?

Answer 1

If you don't want to use a tee, before you write the data, write it to a file, then send it to stdout.

You should write a logging function that does this for you to make it cleaner.