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 。
库
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。