Windows下称为guid，Linux下作为uuid，生成唯一值，可将这种方法用作数据库，作为数据库主键的值。
方法一：利用随机数 #include <stdio.h>
#include <stdlib.h>
#include <string.h> /**
* Create random UUID
*
* @param buf - buffer to be filled with the uuid string
*/
char *random_uuid( char buf[37] )
{
const char *c = "89ab";
char *p = buf;
int n;
for( n = 0; n < 16; ++n )
{
int b = rand()%255;
switch( n )
{
case 6:
sprintf(p, "4%x", b%15 );
break;
case 8:
sprintf(p, "%c%x", c[rand()%strlen(c)], b%15 );
break;
default:
sprintf(p, "%02x", b);
break;
}
p += 2;
switch( n )
{
case 3:
case 5:
case 7:
case 9:
*p++ = '-';
break;
}
}
*p = 0;
return buf;
}
void main()
{
char guid[37];
random_uuid(guid);
printf("guid = %s\n", guid);
random_uuid(guid);
printf("guid = %s\n", guid);
random_uuid(guid);
printf("guid = %s\n", guid);
random_uuid(guid);
printf("guid = %s\n", guid);
}
运行如下：
daniel@debian:~/src$ gcc getuuid.c
daniel@debian:~/src$ ./a.out
guid = a397a255-53be-41fc-996b-521413e9e22d
guid = 518e1f56-0857-49a7-a5d0-528277751b99
guid = 4aed583d-6a52-49d5-b668-8ead955f3c35
guid = b5c48cdd-6c11-453d-91b4-59cfce233d27
方法二：/*libuuid是一个用于生成UUID的C库，具体用法参考http://linux.die.net/man/3/libuuid，在Ubuntu中，可以用下面的命令安装libuuid：
sudo apt-get install uuid-dev 示例如下：*/
#include <stdio.h>
#include <uuid/uuid.h>
int main(int argc, char **argv)
{
uuid_t uuid;
char str[36];
uuid_generate(uuid);
uuid_unparse(uuid, str);
printf("%s\n", str);
return 0;
}
在Linux下编译时需要链接uuid库
gcc -o uuid uuid.c -luuid
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