Click this button to go to the index for this section.

intro(3)
NAME
  intro - Introduction to library functions

DESCRIPTION
  Section 3 reference pages describe functions that may be found in various
  libraries.  The library functions are those other than the functions that
  directly invoke DIGITAL UNIX system primitives, described in Section 2
  reference pages.

  Some reference pages in Section 3 may contain suffixes to allow their files
  to exist with those of other reference pages having the same base name and
  section number. When used, suffixes are made up of one to four letters. See
  the man(1) reference page for more information on suffixes.

  To use the reentrant functions and data structures identified as "obsolete"
  in Section 3 reference pages, it is necessary to define the preprocessor
  symbol _REENTRANT prior to including the associated include file.  If this
  is not done, prototypes and supplementary data structures for these
  functions may not be defined.	 This symbol is defined for you if you use
  the -threads or -pthread switches to the cc or c89 command.

  All libc functions are threadsafe unless otherwise indicated on their
  respective reference pages.  The following table lists non-threadsafe libc
  functions and their threadsafe equivalents (which are provided in libc.so
  for use in multithreaded applications):
  _________________________________________
  Not Threadsafe   Threadsafe Equivalent
  _________________________________________
  asctime	   asctime_r
  ctime		   ctime_r
  endpwent	   endpwent_r
  fgetgrent	   fgetgrent_r
  fgetpwent	   fgetpwent_r
  getgrent	   getgrent_r
  getgrgid	   getgrgid_r
  getgrname	   getgrname_r
  getpwent	   getpwent_r
  getpwnam	   getpwnam_r
  getpwuid	   getpwuid_r
  gmtime	   gmtime_r
  localtime	   localtime_r
  rand		   rand_r
  readdir	   readdir_r
  setpwent	   setpwent_r
  strtok	   strtok_r

  The following functions are not threadsafe and do not have threadsafe
  equivalents:

    registerrpc, svc_destroy, svc_freeargs, svc_getargs, svc_getcaller,
    svc_getreq, svc_getreqset, svc_register, svc_run, svc_sendreply,
    svc_unregister, svcerr_auth, svcerr_decode, svcerr_noproc, svcerr_noprog,
    svcerr_progvers, svcerr_systemerr, svcerr_weakauth, svcfd_create,
    svcraw_create, svctcp_create, svcudp_create, xprt_register,
    xprt_unregister



ERRORS
  Functions in the math library may return conventional values when the
  function is undefined for the given arguments or when the value is not
  representable.  In these cases, the external variable errno is set to the
  value of EDOM (domain error) or ERANGE (range error).	 For further
  information, see intro(2).  The values of EDOM and ERANGE are defined in
  the include file <math.h>.

FILES
  /usr/lib/libc.a

  /usr/lib/libcP.a

  /usr/lib/libm.a

  /usr/lib/libcV.a

RELATED INFORMATION
  cc(1), ld(1), nm(1), intro(2)