%>

比较两个缓冲区中的字符。

语法

int memcmp(
   const void *buffer1,
   const void *buffer2,
   size_t count
);
int wmemcmp(
   const wchar_t * buffer1,
   const wchar_t * buffer2,
   size_t count
);

参数

buffer1
第一个缓冲区。

buffer2
第二个缓冲区。

count
要比较的字符数。 (比较 memcmp的字节,wmemcmp 的宽字符)。

返回值

返回值指示缓冲区之间的关系。

返回值 buf1buf2 的前 count 个字符之间的关系
< 0 buffer1 小于 buffer2
0 buffer1 等于 buffer2
> 0 buffer1 大于 buffer2

备注

比较 buffer1buffer2 的前 count 个字符,并返回指示其关系的值。 非零返回值的符号是缓冲区中的第一个不同值对之差的符号。 值针对 memcmp 解释为 unsigned char,针对 wmemcmp 解释为 wchar_t

要求

例程 必需的标头
memcmp <memory.h><string.h>
wmemcmp <wchar.h>

有关兼容性的详细信息,请参阅 兼容性

C 运行时库的所有版本。

示例

// crt_memcmp.c
/* This program uses memcmp to compare
* the strings named first and second. If the first
* 19 bytes of the strings are equal, the program
* considers the strings to be equal.
*/

#include <string.h>
#include <stdio.h>

int main( void )
{
   char first[]  = "12345678901234567890";
   char second[] = "12345678901234567891";
   int int_arr1[] = {1,2,3,4};
   int int_arr2[] = {1,2,3,4};
   int result;

   printf( "Compare '%.19s' to '%.19s':\n", first, second );
   result = memcmp( first, second, 19 );
   if( result < 0 )
      printf( "First is less than second.\n" );
   else if( result == 0 )
      printf( "First is equal to second.\n" );
   else
      printf( "First is greater than second.\n" );

   printf( "Compare '%d,%d' to '%d,%d':\n", int_arr1[0], int_arr1[1], int_arr2[0], int_arr2[1]);
   result = memcmp( int_arr1, int_arr2, sizeof(int) * 2 );
   if( result < 0 )
      printf( "int_arr1 is less than int_arr2.\n" );
   else if( result == 0 )
      printf( "int_arr1 is equal to int_arr2.\n" );
   else
      printf( "int_arr1 is greater than int_arr2.\n" );
}
Compare '1234567890123456789' to '1234567890123456789':
First is equal to second.
Compare '1,2' to '1,2':
int_arr1 is equal to int_arr2.

另请参阅

缓冲区操作
_memccpy
%>
%>
%>
.- .