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Cx51 User's Guide

Cx51 Introduction Compiling Programs Language Extensions Preprocessor Advanced Programming 8051 Derivatives Error Messages Library Reference Library Files Source Code Standard Types jmp_buf size_t va_list wchar_t Macros CBYTE CWORD DBYTE DWORD FARRAY FCARRAY FCVAR FVAR PBYTE PWORD XBYTE XWORD 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 80c517.h absacc.h assert.h ctype.h float.h intrins.h limits.h math.h rtx51tny.h setjmp.h stdarg.h stddef.h stdio.h stdlib.h string.h Reference _chkfloat_ _crol_ _cror_ _getkey _irol_ _iror_ _lrol_ _lror_ _nop_ _pop_ _push_ _testbit_ _tolower _toupper abs acos acos517 asin asin517 assert atan atan2 atan517 atof atof517 atoi atol cabs calloc ceil cos cos517 cosh exp exp517 fabs floor fmod free getchar gets init_mempool isalnum isalpha iscntrl isdigit isgraph islower isprint ispunct isspace isupper isxdigit labs log log10 log10517 log517 longjmp malloc memccpy memchr memcmp memcpy memmove memset modf offsetof pow printf printf517 putchar puts rand realloc scanf scanf517 setjmp sin sin517 sinh sprintf sprintf517 sqrt sqrt517 srand sscanf sscanf517 strcat strchr strcmp strcpy strcspn strlen strncat strncmp strncpy strpbrk strpos strrchr strrpbrk strrpos strspn strstr strtod strtod517 strtok strtol strtoul switchbank tan tan517 tanh toascii toint tolower toupper ungetchar va_arg va_end va_start vprintf vsprintf Appendix

memcmp

Summary
#include <string.h>

char memcmp (
  void *buf1,   /* first buffer */
  void *buf2,   /* second buffer */
  int len);     /* bytes to compare */
Description

The memcmp function compares the first len bytes from buf1 and buf2 and returns a value indicating their relationship as follows:

Value Description
< 0 buf1 less than buf2
= 0 buf1 equal to buf2
> 0 buf1 greater than buf2
Return Value

The memcmp function returns a positive, negative, or zero value indicating the relationship of buf1 and buf2.

See Also

memccpy, memchr, memcpy, memmove, memset

Example
#include <string.h>
#include <stdio.h> /* for printf */

void tst_memcmp (void) {
  char hexchars [] = "0123456789ABCDEF";
  char hexchars2 [] = "0123456789abcdef";
  char i;

  i = memcmp (hexchars, hexchars2, 16);

  if (i < 0)
    printf ("hexchars < hexchars2\n");
  else if (i > 0)
    printf ("hexchars > hexchars2\n");
  else
    printf ("hexchars == hexchars2\n");
}
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