MySQL 5.7 C API Developer Guide
int
mysql_kill(MYSQL *mysql,
unsigned long pid)
mysql_kill() is deprecated and is subject
to removal in a future version of MySQL. Instead, use
mysql_real_query() or
mysql_query() to execute a
KILL statement.
Asks the server to kill the thread specified by
pid.
mysql_kill() cannot handle
values larger than 32 bits, but to guard against killing the
wrong thread returns an error in these cases:
If given an ID larger than 32 bits,
mysql_kill() returns a
CR_INVALID_CONN_HANDLE
error.
After the server's internal thread ID counter reaches a
value larger than 32 bits, it returns an
ER_DATA_OUT_OF_RANGE error
for any mysql_kill()
invocation and
mysql_kill() fails.
Commands were executed in an improper order.
The pid was larger than 32 bits.
The MySQL server has gone away.
The connection to the server was lost during the query.
An unknown error occurred.
The server's internal thread ID counter has reached a
value larger than 32 bits, at which point it rejects all
mysql_kill() invocations.