/*
alloc.h
memory management functions and variables.
Copyright (c) Borland International 1987,1988
All Rights Reserved.
*/
#if __STDC__
#define _Cdecl
#else
#define _Cdecl
cdecl
#endif
#ifndef _STDDEF
#define _STDDEF
#ifndef _PTRDIFF_T
#define _PTRDIFF_T
#if
defined(__LARGE__) || defined(__HUGE__) || defined(__COMPACT__)
typedef long
ptrdiff_t;
#else
typedef int
ptrdiff_t;
#endif
#endif
#ifndef _SIZE_T
#define _SIZE_T
typedef unsigned size_t;
#endif
#endif
#ifndef NULL
#if defined(__TINY__) || defined(__SMALL__) || defined(__MEDIUM__)
#define NULL
0
#else
#define NULL
0L
#endif
#endif
int
_Cdecl brk
(void *addr);
void
*_Cdecl calloc
(size_t nitems, size_t size);
#if defined(__COMPACT__) || defined(__LARGE__) || defined(__HUGE__)
unsigned long _Cdecl coreleft
(void);
#else
unsigned _Cdecl coreleft
(void);
#endif
void
_Cdecl free
(void *block);
void
*_Cdecl malloc
(size_t size);
void
*_Cdecl realloc
(void *block, size_t size);
void
*_Cdecl sbrk
(int incr);
#if !__STDC__
void far
* _Cdecl farcalloc
(unsigned long nunits, unsigned long unitsz);
unsigned long _Cdecl farcoreleft(void);
void _Cdecl
farfree
(void far *block);
void far
*_Cdecl farmalloc
(unsigned long nbytes);
void far
*_Cdecl farrealloc
(void far *oldblock, unsigned long nbytes);
#endif
解释这些是什么意思?Thanks.