In the document, I found that fgets_unlocked() is not thread-safe. However, I am not sure that can I use fgets_unlocked() without using any lock in a multi-threaded code, but ensure that each thread will access a different file (no two threads will access the same file)?

CodePudding user response：

If each thread uses fgets of any kind to read from different files and write to different buffers, you're safe. There's nothing shared between threads in that case.