SETENV (man3p)
setenv — add or change environment variable
setenv — add or change environment variable
alphasort, scandir — scan a directory
mkstemp — create a unique file
putc — put a byte on a stream
uselocale — use locale in current thread
qsort — sort a table of data
longjmp — non-local goto
wcsnrtombs — convert wide-character string to multi-byte string
wmemchr — find a wide character in memory
getppid — get the parent process ID