libiberty/doc/supplemental-functions.rst

   1 ..
   2   Copyright 1988-2022 Free Software Foundation, Inc.
   3   This is part of the GCC manual.
   4   For copying conditions, see the copyright.rst file.
   5
   6 .. index:: supplemental functions, functions, supplemental, functions, missing
   7
   8 .. _supplemental-functions:
   9
  10 Supplemental Functions
  11 **********************
  12
  13 Certain operating systems do not provide functions which have since
  14 become standardized, or at least common.  For example, the Single
  15 Unix Specification Version 2 requires that the ``basename``
  16 function be provided, but an OS which predates that specification
  17 might not have this function.  This should not prevent well-written
  18 code from running on such a system.
  19
  20 Similarly, some functions exist only among a particular 'flavor'
  21 or 'family' of operating systems.  As an example, the ``bzero``
  22 function is often not present on systems outside the BSD-derived
  23 family of systems.
  24
  25 Many such functions are provided in ``libiberty``.  They are quickly
  26 listed here with little description, as systems which lack them
  27 become less and less common.  Each function :samp:`{foo}` is implemented
  28 in :samp:`{foo}.c` but not declared in any ``libiberty`` header file; more
  29 comments and caveats for each function's implementation are often
  30 available in the source file.  Generally, the function can simply
  31 be declared as ``extern``.