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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

Memory Allocation Routines

Use the memory allocation functions to specify, allocate, and free blocks of memory from a memory pool. All memory allocation functions are implemented as functions and are prototyped in the stdlib.h include file.

Routine Attributes Description
calloc, fcalloc, xcalloc   Allocates storage for an array from the memory pool.
free, ffree, xfree   Frees a memory block that was allocated using calloc, malloc, or realloc.
init_mempool   Initializes the memory location and size of the memory pool.
malloc, fmalloc, xmalloc   Allocates a block from the memory pool.
realloc, frealloc, xrealloc   Reallocates a block from the memory pool.

Before using any of these functions to allocate memory, you must first specify the size and location of the memory pool using the init_mempool routine. All memory requests are satisfied using this memory block.

The calloc and malloc routines allocate blocks of memory from the pool. The calloc routine allocates an array with a specified number of elements of a given size and initializes the array to 0. The malloc routine allocates a specified number of bytes.

The realloc routine changes the size of an allocated block while the free routine returns a previously allocated memory block to the memory pool.

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