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C251 User's Guide

C251 Introduction Compiling Programs Language Extensions Preprocessor Advanced Programming Error Messages Library Reference Library Files Source Code Standard Types jmp_buf va_list Macros CBYTE CVAR CARRAY DARRAY DBYTE DVAR HARRAY HBYTE HVAR NARRAY NBYTE NVAR XARRAY XBYTE XVAR Routines by Category Buffer Manipulation Routines Character Routines Data Conversion Routines Intrinsic Routines Math Routines Memory Allocation Routines Stream I/O Routines String Routines Variable Length Argument Routines Miscellaneous Routines Include Files SFR Definitions absacc.h assert.h ctype.h float.h intrins.h limits.h math.h setjmp.h stdarg.h stddef.h stdio.h stdlib.h string.h Reference _chkdouble_ _chkfloat_ _crol_ _cror_ _getkey _irol_ _iror_ _lrol_ _lror_ _nop_ _testbit_ _tolower _toupper abs acos asin assert atan atan2 atof atoi atol cabs calloc ceil cos cosh exp fabs fcalloc ffree finit_mempool floor fmalloc fmemcpy fmemset frealloc free getchar gets hmemccpy hmemchr hmemcmp hmemcpy hmemmove hmemset hstrcmp hstrcpy hstrlen hstrncpy init_mempool isalnum isalpha iscntrl isdigit isgraph islower isprint ispunct isspace isupper isxdigit labs log log10 longjmp malloc memccpy memchr memcmp memcpy memmove memset modf offsetof pow printf putchar puts rand realloc scanf setjmp sin sinh sprintf sqrt srand sscanf strcat strchr strcmp strcpy strcspn strlen strncat strncmp strncpy strpbrk strpos strrchr strrpbrk strrpos strspn tan tanh toascii toint tolower toupper ungetchar va_arg va_end va_start vprintf vsprintf xcalloc xfree xinit_mempool xmalloc xmemcpy xmemset xrealloc Appendix

xinit_mempool

Summary
#include <stdlib.h>

void xinit_mempool (
  void xhuge *p,           /* start of memory pool */
  unsigned long size);     /* length of memory pool */
Description

The xinit_mempool function initializes the memory management routines and provides the starting address and size of the memory pool. The p argument points to a memory area in xdata which is managed using the xcalloc, xfree, xmalloc, and xrealloc library functions. The size argument specifies the number of bytes to use for the memory pool.

Note

  • This function must be used to setup the memory pool before any other memory management functions (xcalloc, xfree, xmalloc, xrealloc) can be called. Call the xinit_mempool function only once at the beginning of your program.
  • Source code for this routine is provide in the LIB folder. You may modify the source to customize this function for your particular hardware environment.
  • Each memory block needs 8 bytes overhead to handle the allocation information. In addition another 8 bytes are required for init_mempool itself. Therefore if you want to allocate 2 blocks with 100 bytes each, the memory pool size must be 224 bytes.
Return Value

None.

See Also

xcalloc, xfree, xmalloc, xrealloc

Example
#include <stdlib.h>

void tst_init_mempool (void) {
  xdata void *p;
  int i;

/* initialize memory pool at xdata 0x2000 for 4096 bytes */
  xinit_mempool (&XBYTE [0x2000], 0x1000);

  p = xmalloc (100);

  for (i = 0; i < 100; i++)
    ((char *) p)[i] = i;

  xfree (p);
}
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