Se cerchi informazioni su una specifica funzione e hai i pacchetti della documentazione installati puoi usare man; ad esempio
codice:
man pthread_create
PTHREAD_CREATE(P) POSIX Programmer's Manual PTHREAD_CREATE(P)
NAME
pthread_create - thread creation
SYNOPSIS
#include <pthread.h>
int pthread_create(pthread_t *restrict thread,
const pthread_attr_t *restrict attr,
void *(*start_routine)(void*), void *restrict arg);
DESCRIPTION
The pthread_create() function shall create a new thread, with
attributes specified by attr, within a process. If attr is NULL, the
default attributes shall be used. If the attributes specified by attr
are modified later, the thread's attributes shall not be affected. Upon
successful completion, pthread_create() shall store the ID of the cre‐
ated thread in the location referenced by thread.
The thread is created executing start_routine with arg as its sole
argument. If the start_routine returns, the effect shall be as if there
was an implicit call to pthread_exit() using the return value of
(eccetera)