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      1 /* Memory allocation on the stack.
      2    Copyright (C) 1995, 1999, 2001-2005 Free Software Foundation, Inc.
      3 
      4    This program is free software; you can redistribute it and/or modify it
      5    under the terms of the GNU General Public License as published
      6    by the Free Software Foundation; either version 2, or (at your option)
      7    any later version.
      8 
      9    This program is distributed in the hope that it will be useful,
     10    but WITHOUT ANY WARRANTY; without even the implied warranty of
     11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     12    General Public License for more details.
     13 
     14    You should have received a copy of the GNU General Public
     15    License along with this program; if not, write to the Free Software
     16    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
     17    USA.  */
     18 
     19 /* When this file is included, it may be preceded only by preprocessor
     20    declarations.  Thanks to AIX.  Therefore we include it right after
     21    "config.h", not later.  */
     22 
     23 /* Avoid using the symbol _ALLOCA_H here, as Bison assumes _ALLOCA_H
     24    means there is a real alloca function.  */
     25 #ifndef _GNULIB_ALLOCA_H
     26 #define _GNULIB_ALLOCA_H
     27 
     28 /* alloca(N) returns a pointer (void* or char*) to N bytes of memory
     29    allocated on the stack, and which will last until the function returns.
     30    Use of alloca should be avoided:
     31      - inside arguments of function calls - undefined behaviour,
     32      - in inline functions - the allocation may actually last until the
     33        calling function returns,
     34      - for huge N (say, N >= 65536) - you never know how large (or small)
     35        the stack is, and when the stack cannot fulfill the memory allocation
     36        request, the program just crashes.
     37  */
     38 
     39 #if defined(__GNUC__) || defined(__lint__)
     40 # ifndef alloca
     41 #  define alloca __builtin_alloca
     42 # endif
     43 #else
     44 # ifdef _MSC_VER
     45 #  include <malloc.h>
     46 #  define alloca _alloca
     47 # else
     48 #  if HAVE_ALLOCA_H
     49 #   include <alloca.h>
     50 #  else
     51 #   ifdef _AIX
     52  #pragma alloca
     53 #   else
     54 #    ifdef __hpux /* This section must match that of bison generated files. */
     55 #     ifdef __cplusplus
     56 extern "C" void *alloca (unsigned int);
     57 #     else /* not __cplusplus */
     58 extern void *alloca ();
     59 #     endif /* not __cplusplus */
     60 #    else /* not __hpux */
     61 #     ifndef alloca
     62 extern char *alloca ();
     63 #     endif
     64 #    endif /* __hpux */
     65 #   endif
     66 #  endif
     67 # endif
     68 #endif
     69 
     70 #endif /* _GNULIB_ALLOCA_H */
     71