How to buffer stdout in memory and write it from a dedicated thread

Question

I have a C application with many worker threads. It is essential that these do not block so where the worker threads need to write to a file on disk, I have them write to a

Answer 1

The method using the 4096 bigbuf will only sort of work. I've tried this code, and while it does successfully capture stdout into the buffer, it's unusable in a real world case. You have no way of knowing how long the captured output is, so no way of knowing when to terminate the string '\0'. If you try to use the buffer you get 4000 characters of garbage spit out if you had successfully captured 96 characters of stdout output.

In my application, I'm using a perl interpreter in the C program. I have no idea how much output is going to be spit out of what ever document is thrown at the C program, and hence the code above would never allow me to cleanly print that output out anywhere.