SQLSetEnvAttr
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Azure Synapse Analytics
Analytics Platform System (PDW)
The ODBC Programmer's Reference defines how ODBC drivers should interpret the SQLSetEnvAttr attribute specifications from applications written to either the ODBC 2.x or ODBC 3.x API. The SQL Server Native Client ODBC driver complies with those rules.
One of the attributes controlled by SQLSetEnvAttr is whether connection pooling is to be used. If connection pooling is used with the SQL Server Native Client ODBC driver, the DriverCompletion parameter must be set to SQL_DRIVER_NOPROMPT when connecting with either SQLDriverConnect or SQLConnect.