How does php call stored procedures with returned results?

This is a problem that has not been solved by the returnee who used the CI framework to call the stored procedure. after reading the technical documentation, I can extract it because the project has been in use for a long time.

This is a problem that has not been solved when a returnee has an error in calling the stored procedure using the CI framework. after reading the technical documentation, I can extract it because the project has been in use for a long time, now there is no time for testing. for example, you can leave a message when you encounter problems...

MySQL extension also supports stored procedures, but only supports stored procedures with no returned results. if the stored procedure has an output, this call will throw an error. the specific error is missing. The call method is simple:
$ Rs = mysql_query ("call func ('str')", $ conn );
If a returned result is returned, for example, a string, an error is returned. the solution I have found is to use the MySQLi extension:
$ Rs = mysqli_query ("call func ('str')", $ conn );
In this way, $ rs is used as a normal MySQL Result, which is very convenient.