microsoft odbc drivermanager SQLColAttribute SQL_INVALID_HANDLE - odbc

Question

I'm getting SQL_INVALID_HANDLE error when calling SQLColAttribute from an application (trying to communicate with self developed odbc driver) I don't know why the handle is stated an invalid handle, since its a simple struct, which is still valid at runtime, ive checked it. The driver is a non unicode driver and im using it from a non unicode test application.
The driver also manages to set (log from the driver)
SQLGetStmtAttr called:
Attribute to set is: SQL_ATTR_APP_ROW_DESC
SQLGetStmtAttr called:
Attribute to set is: SQL_ATTR_APP_PARAM_DESC
SQLGetStmtAttr called:
Attribute to set is: SQL_ATTR_IMP_ROW_DESC
SQLGetStmtAttr called:
Attribute to set is: SQL_ATTR_IMP_PARAM_DESC
properly before calling sqlprepare
the driver manager log:
ODBC_Test 2210-151c ENTER SQLAllocHandle
SQLSMALLINT 1 <SQL_HANDLE_ENV>
SQLHANDLE 0x00000000
SQLHANDLE * 0x002EFCC0
ODBC_Test 2210-151c EXIT SQLAllocHandle with return code 0 (SQL_SUCCESS)
SQLSMALLINT 1 <SQL_HANDLE_ENV>
SQLHANDLE 0x00000000
SQLHANDLE * 0x002EFCC0 ( 0x003541C8)
ODBC_Test 2210-151c ENTER SQLSetEnvAttr
SQLHENV 0x003541C8
SQLINTEGER 200 <SQL_ATTR_ODBC_VERSION>
SQLPOINTER 3 <SQL_OV_ODBC3>
SQLINTEGER 0
ODBC_Test 2210-151c EXIT SQLSetEnvAttr with return code 0 (SQL_SUCCESS)
SQLHENV 0x003541C8
SQLINTEGER 200 <SQL_ATTR_ODBC_VERSION>
SQLPOINTER 3 <SQL_OV_ODBC3>
SQLINTEGER 0
ODBC_Test 2210-151c ENTER SQLAllocHandle
SQLSMALLINT 2 <SQL_HANDLE_DBC>
SQLHANDLE 0x003541C8
SQLHANDLE * 0x002EFCA8
ODBC_Test 2210-151c EXIT SQLAllocHandle with return code 0 (SQL_SUCCESS)
SQLSMALLINT 2 <SQL_HANDLE_DBC>
SQLHANDLE 0x003541C8
SQLHANDLE * 0x002EFCA8 ( 0x00354250)
ODBC_Test 2210-151c ENTER SQLConnectW
HDBC 0x00354250
WCHAR * 0x00352EB8 [ 5] "dsn01"
SWORD 5
WCHAR * 0x55128B34 [ -3] "******\ 0"
SWORD -3
WCHAR * 0x55128B34 [ -3] "******\ 0"
SWORD -3
ODBC_Test 2210-151c EXIT SQLConnectW with return code 0 (SQL_SUCCESS)
HDBC 0x00354250
WCHAR * 0x00352EB8 [ 5] "dsn01"
SWORD 5
WCHAR * 0x55128B34 [ -3] "******\ 0"
SWORD -3
WCHAR * 0x55128B34 [ -3] "******\ 0"
SWORD -3
ODBC_Test 2210-151c ENTER SQLAllocHandle
SQLSMALLINT 3 <SQL_HANDLE_STMT>
SQLHANDLE 0x00354250
SQLHANDLE * 0x002EF6F8
ODBC_Test 2210-151c EXIT SQLAllocHandle with return code 0 (SQL_SUCCESS)
SQLSMALLINT 3 <SQL_HANDLE_STMT>
SQLHANDLE 0x00354250
SQLHANDLE * 0x002EF6F8 ( 0x00355790)
ODBC_Test 2210-151c ENTER SQLPrepare
HSTMT 0x00355790
UCHAR * 0x00DB89C8 [ 72] "select COUNTRYFR,CITYFROM,CITYTO from SPFLI where CITYFROM EQ 'NEW YORK'"
SDWORD 72
ODBC_Test 2210-151c EXIT SQLPrepare with return code 0 (SQL_SUCCESS)
HSTMT 0x00355790
UCHAR * 0x00DB89C8 [ 72] "select COUNTRYFR,CITYFROM,CITYTO from SPFLI where CITYFROM EQ 'NEW YORK'"
SDWORD 72
ODBC_Test 2210-151c ENTER SQLColAttribute
SQLHSTMT 0x00355790
SQLSMALLINT 1
SQLSMALLINT 14 <SQL_DESC_TYPE_NAME>
SQLPOINTER 0x002EF6B0
SQLSMALLINT 50
SQLSMALLINT * 0x002EF6A4
SQLPOINTER 0x00000000 (NYI)
ODBC_Test 2210-151c ENTER SQLColAttribute
SQLHSTMT 0x00C05200
SQLSMALLINT 1
SQLSMALLINT 14 <SQL_DESC_TYPE_NAME>
SQLPOINTER 0x002EF6B0
SQLSMALLINT 50
SQLSMALLINT * 0x002EF6A4
SQLPOINTER 0x00000000 (NYI)
ODBC_Test 2210-151c EXIT SQLColAttribute with return code -2 (SQL_INVALID_HANDLE)
SQLHSTMT 0x00C05200
SQLSMALLINT 1
SQLSMALLINT 14 <SQL_DESC_TYPE_NAME>
SQLPOINTER 0x002EF6B0
SQLSMALLINT 50
SQLSMALLINT * 0x002EF6A4
SQLPOINTER 0x00000000 (NYI)
ODBC_Test 2210-151c EXIT SQLColAttribute with return code -2 (SQL_INVALID_HANDLE)
SQLHSTMT 0x00355790
SQLSMALLINT 1
SQLSMALLINT 14 <SQL_DESC_TYPE_NAME>
SQLPOINTER 0x002EF6B0
SQLSMALLINT 50
SQLSMALLINT * 0x002EF6A4
SQLPOINTER 0x00000000 (NYI)
The test program is pretty simple:
SQLHANDLE hEnv ;
SQLAllocHandle( SQL_HANDLE_ENV, SQL_NULL_HANDLE, &hEnv ) ;
SQLSetEnvAttr( hEnv, SQL_ATTR_ODBC_VERSION, (void*)SQL_OV_ODBC3, 0 ) ;
SQLHANDLE hConn ;
SQLAllocHandle( SQL_HANDLE_DBC, hEnv, &hConn );
SQLCHAR* dsnName = (SQLCHAR*)"dsn01" ; // MUST BE THE SAME
SQLCHAR* userid = (SQLCHAR*)"nodata\0";
SQLCHAR* password = (SQLCHAR*)"nodata\0";
SQLConnect(
hConn,
dsnName,
5,
userid,
SQL_NTS,
password,
SQL_NTS);
HSTMT hStmt ;
SQLAllocHandle( SQL_HANDLE_STMT, hConn, &hStmt ) ;
SQLCHAR* query = (SQLCHAR*)"select COUNTRYFR,CITYFROM,CITYTO from SPFLI where CITYFROM EQ 'NEW YORK'";
SQLPrepare(hStmt,query,strlen((const char*)query));
SQLCHAR TypeName[50];
SQLSMALLINT TypeNameLen;
SQLColAttribute((SQLHSTMT)hStmt,1,SQL_DESC_TYPE_NAME,TypeName, sizeof(TypeName),&TypeNameLen,NULL);
Anyone knows what can cause SQLColAttribute to give back SQL_INVALID_HANDLE ? I've read msdn but nothing useful was there.

Answer 1

You allocated a statement handle which is 0x00355790. You prepared it. It all goes wrong as you say when you call SQLColAttribute. The log suggests that SQLColAttribute was called correctly with the statement handle but then (your driver?) called SQLColAttribute again with a different handle. My guess is you've got a function name clash in your driver.

Answer 2

See this declaration in sqlucode.h :
// UNICODE versions
#ifdef _WIN64
SQLRETURN SQL_API SQLColAttributeW
(
SQLHSTMT hstmt,
SQLUSMALLINT iCol,
SQLUSMALLINT iField,
_Out_writes_bytes_opt_(cbDescMax)
SQLPOINTER pCharAttr,
SQLSMALLINT cbDescMax,
_Out_opt_
SQLSMALLINT *pcbCharAttr,
_Out_opt_
SQLLEN *pNumAttr
);
#else
SQLRETURN SQL_API SQLColAttributeW(
SQLHSTMT hstmt,
SQLUSMALLINT iCol,
SQLUSMALLINT iField,
_Out_writes_bytes_opt_(cbDescMax)
SQLPOINTER pCharAttr,
SQLSMALLINT cbDescMax,
_Out_opt_
SQLSMALLINT *pcbCharAttr,
_Out_opt_
SQLPOINTER pNumAttr);
#endif
and understand how difficult it is
> (for me) to avoid the function name clash in both cases (x64/x86)
> (for microsoft) to write correct doc