PTHREAD_KEY_CREATE (man3p)
pthread_key_create — thread-specific data key creation
pthread_key_create — thread-specific data key creation
atanh, atanhf, atanhl — inverse hyperbolic tangent functions
towlower, towlower_l — transliterate uppercase wide-character code to lowercase
wcwidth — number of column positions of a wide-character code
pthread_mutexattr_getprioceiling, pthread_mutexattr_setprioceiling — get and set the prioceiling attribute of the mutex attributes object (REALTIME THREADS)
acosh, acoshf, acoshl — inverse hyperbolic cosine functions
mbstowcs — convert a character string to a wide-character string
ptsname — get name of the slave pseudo-terminal device
wcsdup — duplicate a wide-character string
timezone — difference from UTC and local standard time