如何在C语言中生成基于熵的UUID并将其存储为字符串(字符指针)?
我希望有一个简单的内部方法,但是system("uuidgen -r")
可以解决这个问题。
答案 0 :(得分:4)
libuuid
提供了此功能。 (在Debian上打包libuuid1
和uuid-dev
。)
这是一个简单的程序,它生成基于熵的(随机)UUID,并将其写入stdout
,然后以状态0
退出。
/* For malloc() */
#include <stdlib.h>
/* For puts()/printf() */
#include <stdio.h>
/* For uuid_generate() and uuid_unparse() */
#include <uuid/uuid.h>
/* Uncomment to always generate capital UUIDs. */
//#define capitaluuid true
/* Uncomment to always generate lower-case UUIDs. */
//#define lowercaseuuid true
/*
* Don't uncomment either if you don't care (the case of the letters
* in the 'unparsed' UUID will depend on your system's locale).
*/
int main(void) {
uuid_t binuuid;
/*
* Generate a UUID. We're not done yet, though,
* for the UUID generated is in binary format
* (hence the variable name). We must 'unparse'
* binuuid to get a usable 36-character string.
*/
uuid_generate_random(binuuid);
/*
* uuid_unparse() doesn't allocate memory for itself, so do that with
* malloc(). 37 is the length of a UUID (36 characters), plus '\0'.
*/
char *uuid = malloc(37);
#ifdef capitaluuid
/* Produces a UUID string at uuid consisting of capital letters. */
uuid_unparse_upper(binuuid, uuid);
#elif lowercaseuuid
/* Produces a UUID string at uuid consisting of lower-case letters. */
uuid_unparse_lower(binuuid, uuid);
#else
/*
* Produces a UUID string at uuid consisting of letters
* whose case depends on the system's locale.
*/
uuid_unparse(binuuid, uuid);
#endif
// Equivalent of printf("%s\n", uuid); - just my personal preference
puts(uuid);
return 0;
}
uuid_unparse()
不会分配自己的内存;为了避免执行时出现分段错误,您必须使用uuid = malloc(37);
手动进行操作(您也可以将UUID存储在长度为char uuid[37];
的char数组中)。确保使用-luuid
进行编译,以使链接器知道uuid_generate_random()
中定义了uuid_unparse()
和libuuid
。
答案 1 :(得分:0)
在 Linux 上,您可以使用
/* uuid.c
*
* Defines function uuid
*
* Print a universally unique identifer, created using Linux uuid_generate.
*
*
* Compile
*
* gcc uuid.c -o uuid -luuid -Wall -g
*
*
* Run
*
* ./uuid
*
*
* Debug
*
* gdb uuid
* b main
* r
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <uuid/uuid.h>
char* uuid(char out[UUID_STR_LEN]){
uuid_t b;
uuid_generate(b);
uuid_unparse_lower(b, out);
return out;
}
int main(){
char out[UUID_STR_LEN]={0};
puts(uuid(out));
return EXIT_SUCCESS;
}