Hi: I write a simple service for L4/Fiasco which encapsulate two methods. clock_gettime() and clock_nanosleep(). Of course now it doesn't not have full functions of these two methods. But when I compile the client application for this server. It has some errors like this: PWD=/home/fiasco/L4.17/build/pkg/clock/examples/client/OBJ-x86_586-l4v2 make -C /home/fiasco/L4.17/build/pkg/clock/examples/client/OBJ-x86_586-l4v2 -f Makefile make[1]: Entering directory `/home/fiasco/L4.17/build/pkg/clock/examples/client/OBJ-x86_586-l4v2' ==> Linking clk LD_PRELOAD=/home/fiasco/L4.17/l4/tool/gendep/libgendep.so GENDEP_TARGET=clk GENDEP_BINARY=ld gcc -o clk /home/fiasco/L4.17/build/lib/x86_586/crt0.o main.o -Ttext=0x01100000 -L/home/fiasco/L4.17/build/lib/x86_586/l4v2 -L/home/fiasco/L4.17//lib/x86_586/l4v2 -L/home/fiasco/L4.17/build/lib/x86_586 -L/home/fiasco/L4.17//lib/x86_586 -L/home/fiasco/L4.17/build/lib -L/home/fiasco/L4.17//lib -T/home/fiasco/L4.17/build/lib/x86_586/main_stat.ld -lclock -static -lgeneric_ts -ll4env -ll4rm -ldm_generic -ldm_mem -lthread -lsemaphore -llogserver_capsule -lnames -ll4util_root -ll4util -lsigma0 -lroot -ll4env -ll4env_err -ll4rm -ldm_generic -ldm_mem -lthread -lslab -ll4sys -nostdlib -Wl,--nostdlib -luc_c -luclibc_support -u mmap_anon -lc_be_simple_mem -lc_be_mmap -lc_be_mmap_util -lc_be_l4env_start_stop -lc_be_minimal_log_io -luc_be_simple_sleep -ll4env -llogserver_capsule -ll4rm -ldm_generic -ldm_mem -lthread -lgeneric_ts -luc_c /usr/lib/gcc/i486-linux-gnu/3.4.6/libgcc.a -luc_c -ll4sys -Ttext=0x01100000 -Wl,--warn-common -Wl,-gc-sections main.o: In function `main':/home/fiasco/L4.17/l4/pkg/clock/examples/client/main.c:11: undefined reference to `clock_gettime' collect2: ld returned 1 exit status make[1]: *** [clk] Error 1 make[1]: Leaving directory `/home/fiasco/L4.17/build/pkg/clock/examples/client/OBJ-x86_586-l4v2' make: *** [/home/fiasco/L4.17/build/pkg/clock/examples/client/OBJ-x86_586-l4v2] Error 2 it says there is no declaration of clock_gettime(). But according to the same method as showing in BID tutorial my hello example runs well. There is attachment of all my source code file. Please help me and I have this problem for many days. Thank you. Cheng