memcmp, wmemcmp

比较两种缓冲区的字符。

int memcmp(
   const void *buf1,
   const void *buf2,
   size_t count
);
int wmemcmp(
   const wchar_t * buf1,
   const wchar_t * buf2,
   size_t count
);

参数

  • buf1
    第一个缓冲区。

  • buf2
    第二个缓冲区。

  • count
    字符 ( memcmp的字节, wmemcmp的宽字符) 的数字。

返回值

返回值指示缓冲区之间的关系。

返回值

第一个绑定字节关系 buf1 和 buf2

< 0

buf1 小于 buf2

0

buf1 与 buf2

> 0

buf1 大于 buf2

备注

比较 buf1 和 buf2 第一 count 字符并返回指示它们之间的关系的值。

要求

实例

必需的头

memcmp

memory.h 或 string.h

wmemcmp

wchar.h

有关其他的兼容性信息,请参见中介绍的 兼容性

C 运行库的所有版本。

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" );
}

Output

Compare '1234567890123456789' to '1234567890123456789':
First is equal to second.
Compare '1,2' to '1,2':
int_arr1 is equal to int_arr2.

.NET Framework 等效项

不适用。若要调用标准 C 函数,请使用 PInvoke。有关更多信息,请参见 平台调用示例

请参见

参考

缓冲区处理

_memccpy

memchr, wmemchr

memcpy, wmemcpy

memset, wmemset

strcmp, wcscmp, _mbscmp

strncmp, wcsncmp, _mbsncmp, _mbsncmp_l