How do I get the standard output of the program being tested?

[NikParam42]

Hi! Tell me please
How do I access stderr stdout of the program we are testing?

I compiled my program this way (using memory sanitizer):

afl-gcc -fsaninite=address -g main.c -o myprog

Next, I run the fuzzer, but how do I get stderr myprog ??

[jonathanmetzman]

You need to modify the program to output stdout and stderr to a location you desire.
afl_driver.cpp does this.