Name patterns reserved by each standard header file
The C and POSIX standards define conventions for the names used by each header file. New user-namespace names can be added to each header file without breaking compliance if they conform to one of the conventional patterns for that header.
The list below was formerly the file NAMESPACE in the source tree. It has not been updated since 2000, and should be carefully checked before doing anything with the information. Ultimately, it would be good to have this in the manual.
Header Prefix Suffix aio.h aio_, lio_, AIO_, LIO_ complex.h cerf{,f,l}, cerfc{,f,l}, cexp2{,f,l}, cexpm1{,f,l}, clog10{,f,l}, clog1p{,f,l}, clog2{,f,l}, clgamma{,f,l}, ctgamma{,f,l} ctype.h is[a-z], to[a-z] dirent.h d_ dlfcn.h RTLD_ errno.h E fcntl.h l_, F_, O_, S_ fmtmsg.h MM_ fnmatch.h FNM_ ftw.h FTW glob.h gl_, GLOB_ grp.h gr_ inttypes.h PRI[a-zX], SCN[a-zX] limits.h _MAX locale.h LC_[A-Z] mqueue.h mq_, MQ_ ndbm.h dbm_, DBM_ nl_types.h NL_ poll.h pd_, ph_, ps_, POLL pthread.h pthread_, PTHREAD_ pwd.h pw_ regex.h re_, rm_, REG_ sched.h sched_, SCHED_ semaphore.h sem_, SEM_ signal.h sa_, uc_, SIG[A-Z], SIG_[A-Z], SIG_[0-9a-z_] ss_, sv_ si_, SI_, sigev_, SIGEV_, sival_, SA_, BUS_, CLD_, FPE_, ILL_, POLL_, SEGV_, SS_, SV_, TRAP_ stdint.h int*_t, uint*_t, INT*_MAX, INT*_MIN, INT*_C, UINT*_MAX, UINT*_MIN, UINT*_C stdlib.h str[a-z] string.h str[a-z], wcs[a-z] stropts.h bi_, ic_, l_, sl_, str_, FLUSH[A-Z], I_, M_, MUXID_R[A-Z], S_, SND[A-Z], STR syslog.h LOG_ sys/ipc.h ipc_, IPC_ sys/mman.h shm_, MAP_, MCL_, MS_, PROT_ sys/msg.h msg, MSG[A-Z], MSG_[A-Z] sys/resource.h rlim_, ru_, PRIO_, RLIM_, RLIMIT_, RUSAGE_ sys/sem.h sem, SEM_ sys/shm.h shm, SHM[A-Z], SHM_[A-Z] sys/socket.h AF_, MSG_, PF_, SO sys/stat.h st_, S_ sys/statvfs.h f_, ST_ sys/time.h fds_, it_, tv_, FD_, ITIMER_ sys/times.h tms_ sys/uio.h iov_, IOV_ sys/utsname.h uts_ sys/wait.h si_, W[A-Z], P_, BUS_, CLD_, FPE_, ILL_, POLL_, SEGV_, SI_, TRAP_ termios.h c_, V, I, O, TC, B[0-9] time.h tm_ clock_, timer_, it_, tv_, CLOCK_, TIMER_ ucontext.h uc_, SS_ ulimit.h UL_ utime.h utim_ utmpx.h ut_ _LVL, _TIME, _PROCESS wchar.h wcs[a-z] wctype.h is[a-z], to[a-z] wordexp.h we_, WRDE_ ANY header _t