mysql的last_insert_id()是不是可靠的？

my_ulonglong STDCALL mysql_insert_id(MYSQL *mysql)

{

return mysql->;last_used_con->;insert_id;

}

typedef struct st_mysql

{

NET net; /* Communication parameters */

gptr connector_fd; /* ConnectorFd for SSL */

char *host,*user,*passwd,*unix_socket,*server_version,*host_info,*info;

char *db;

struct charset_info_st *charset;

MYSQL_FIELD *fields;

MEM_ROOT field_alloc;

my_ulonglong affected_rows;

my_ulonglong insert_id; /* id if insert on table with NEXTNR */

my_ulonglong extra_info; /* Used by mysqlshow */

unsigned long thread_id; /* Id for connection in server */

unsigned long packet_length;

unsigned int port;

unsigned long client_flag,server_capabilities;

unsigned int protocol_version;

unsigned int field_count;

unsigned int server_status;

unsigned int server_language;

unsigned int warning_count;

struct st_mysql_options options;

enum mysql_status status;

my_bool free_me; /* If free in mysql_close */

my_bool reconnect; /* set to 1 if automatic reconnect */

/* session-wide random string */

char scramble[SCRAMBLE_LENGTH+1];

/*

Set if this is the original connection, not a master or a slave we have

added though mysql_rpl_probe() or mysql_set_master()/ mysql_add_slave()

*/

my_bool rpl_pivot;

/*

Pointers to the master, and the next slave connections, points to

itself if lone connection.

*/

struct st_mysql* master, *next_slave;

struct st_mysql* last_used_slave; /* needed for round-robin slave pick */

/* needed for send/read/store/use result to work correctly with replication */

struct st_mysql* last_used_con;

LIST *stmts; /* list of all statements */

const struct st_mysql_methods *methods;

void *thd;

/*

Points to boolean flag in MYSQL_RES or MYSQL_STMT. We set this flag

from mysql_stmt_close if close had to cancel result set of this object.

*/

my_bool *unbuffered_fetch_owner;

} MYSQL;