LOG2 (man3p)
log2, log2f, log2l — compute base 2 logarithm functions
log2, log2f, log2l — compute base 2 logarithm functions
cproj, cprojf, cprojl — complex projection functions
log10, log10f, log10l — base 10 logarithm function
ctime, ctime_r — convert a time value to a date and time string
vwscanf — wide-character formatted input of a stdarg argument list
pthread_rwlock_timedwrlock — lock a read-write lock for writing
acosl — arc cosine functions
chown, fchownat — change owner and group of a file
towupper, towupper_l — transliterate lowercase wide-character code to uppercase
pthread_cleanup_pop, pthread_cleanup_push — establish cancellation handlers