1uClibc attempts to fully (and rigorously) support "The Open Group Base
2Specifications Issue 6 IEEE Std 1003.1, 2003 Edition" (aka SuSv3).  However, as
3with any standard, they sometimes require things that are either impossible or
4are Completely Stupid(tm).  Therefore, we cannot claim full compliance, and
5there may be some areas of uClibc that differ from the requirements of this
6specification.  This document attempts to list these differences and, when
7completed, will contain a full list of all relevant differences between uClibc
8and the requirements of the SuSv3.
9
10
11*) The uClibc setlocale() function is not threadsafe.
12
13    SuSv3 states that "The locale state is common to all threads
14    within a process.".  But it does not explicitly mention
15    setlocale() as a function that need not be thread-safe.
16    Making setlocale() threadsafe would require an absurd amount
17    of locking (i.e. inside each and every ctype call such as
18    isalpha()).  Furthermore, we consider calling setlocale()
19    from N threads concurrently while using string functions to
20    be a terribly dumb thing to do.  Therefore, we have decided
21    that setlocale() shall not be threadsafe.  If you are
22    multi-threaded, and you wish to change the global locale
23    state, please take care to prevent all other threads from
24    using any locale or ctype functions until the setlocale()
25    call has finished.
26
27
28
29
30----------------------------------------------------------------
31heukelum -- heukelum at freemail dot nl writes:
32
33Hi everyone,
34
35I think uClibc is a great project! And, since I found the file
36docs/uClibc_vs_SuSv3.txt in the source tarball which mentioned only
37fmtmsg as a missing function compared to the SUSv3, I got curious about
38the length of the list denoted by "<others?>". So I built the
3920040305-snapshot using allyesconfig, extracted the symbols from the
40(dynamic) libraries, and compared that list to the SUSv3 header files...
41
42The largest source of omissions was the mathematical interface
43(183/355), followed by optional interfaces (134/355). The result: only
4438 non-mathematical interfaces are missing compared to the minimal
45SUSv3! Naming only one function as missing was over-enthousiastic, but
46the result was better than I anticipated.
47
48A compact list of omissions is appended.
49I hope this was a helpful exercise ;)
50
51Greetings,
52         Alexander
53
54P.S. uClibc was compiled with thread support, but did not provide the
55interfaces pthread_cleanup_push and pthread_cleanup_pop.
56
57
58
59Omissions from obligatory interfaces:
60-------------------------------------
61stdlib.h: _Exit, lcong48, lldiv, posix_openpt;
62          ecvt, fcvt
63ndbm.h: [all=9] dbm_*
64utmpx.h: [all=6] *utx* (but functions without "x" do exist!)
65nl_types.h: [all] catclose, catgets, catopen
66unistd.h: getwd, ualarm
67inttypes.h: imaxdiv
68fmtmsg.h: fmtmsg
69string.h: strerror_r
70setjmp.h: setsigjmp
71monetary.h: strfmon
72sys/select.h: pselect
73sys/socket.h: sockatmark
74sys/wait.h: waitid
75
76
77Unimplemented optional interfaces:
78----------------------------------
79trace.h: (depends on TRC) [all=50] posix_trace_*
80pthread.h: (depends on THR) pthread_cleanup_{push,pop};
81         pthread_attr_{g,s}etstack (depend on TSA TSS);
82         [7] pthread_barrier* (depend on BAR);
83         pthread_condattr_{g,s}et_clock (depend on CS);
84         pthread_getcpuclockid (depends on TCT);
85         pthread_mutex{,attr}_{g,s}etprioceiling (depend on TPP);
86         pthread_mutexattr_{g,s}etprotocol (depend on TPP|TPI);
87         pthread_rwlock_timed{rd,rw}lock (depend on TMO);
88         pthread_setschedprio (depends on TPS);
89         [5] pthread_spin_* (depend on SPI)
90spawn.h: (depends on SPN) [all=21] posix_spawn*
91aio.h: (depends on AIO) [all=8] aio_*, lio_*
92stropts.h: (depends on XSR) isastream, {g,s}et{,p}msg, fattach, fdetach
93sys/mman.h: posix_madvice (depends on ADV); posix_mem_offset,
94         posix_typed_mem_getinfo, posix_typed_mem_open (depend on TYM);
95         shm_open, shm_unlink (depend on SHM)
96fcntl.h: posix_fallocate (depend on ADV)
97signal.h: sigqueue (depends on RTS)
98
99
100Unimplemented mathematical interfaces:
101--------------------------------------
102math.h: [126] many
103complex.h: [46] all, except cabs
104fenv.h: [11] all
105_______________________________________________
106