HelenOS sources

root/uspace/lib/c/generic/

[..]
adt/ arg_parse.c as.c assert.c async/
capa.c config.c context.c crt/ dbgcon.c
ddi.c device/ dirent.c dlfcn.c double_to_str.c
elf/ errno.c event.c getopt.c ieee_double.c
imath.c inttypes.c io/ ipc.c irq.c
l18n/ libc.c loader.c loc.c malloc.c
ns.c pcb.c perm.c pio_trace.c power_of_ten.c
private/ rndgen.c rtld/ setjmp.c shutdown.c
smc.c stack.c stacktrace.c stats.c stdio.c
stdio/ stdlib.c string.c sysinfo.c task.c
thread/ time.c tmpfile.c ubsan.c udebug.c
uuid.c vfs/
[..]
HelenOS homepage, sources at GitHub