problem about ipc

hi! 1.i find there is l4_ipc_error( ) ops like that in .h files,but where can i find the implementation of that func? 2.l4_ipc_error( ),return 4,i look up in l4re document it means L4_ENOT_EXISTENT.but how can i solve that? thanks! 发自 Android 版 Yahoo! 邮箱