POSIX Thread (pthread)
pthread.h is a header file in C that provides access to the POSIX thread libraries.
POSIX (Portable Operating System Interface) is a family of standards specified by the IEEE for maintaining compatibility between operating systems. pthread.h is used extensively in UNIX and Linux-based systems.
C-based, low-level API. Offers detailed control over threads.
Pthread vs. thread (C++)?
Pthread is compatible with C, whereas thread was only introduced in C++11.
Which one is better? I don’t know enough to comment.