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Hello,
I've a little problem in a multithread aplication
using DB2 CLI API. See first an extract of the code
------------------------------------------------------------------------------------------------------------------------------------------
struct
tableEntry{
SQLCHAR tableName[11]; SQLINTEGER lastId; SQLHSTMT hstmt; /* prepared statement for update */ struct tableEntry* nextTableEntry; }; struct
schemaEntry{
SQLCHAR schemaName[11]; SQLCHAR tableCounterName[11]; int tablesNumber; struct tableEntry* tableEntry; struct schemaEntry* nextSchemaEntry; }; . .
.
/* global sql variables */
struct schemaEntry* firstSchema; SQLHENV henv; SQLHDBC hdbc; SQLCHAR msgFmt[80]; . .
.
SQLRETURN updateTable( struct schemaEntry* se,
struct tableEntry* te )
{ SQLRETURN returnCode; if( !te->hstmt
){
returnCode = SQLAllocHandle( SQL_HANDLE_STMT, hdbc, &(te->hstmt)); CHECK_HANDLE( SQL_HANDLE_DBC, hdbc, returnCode ); if( returnCode != SQL_SUCCESS ) return returnCode; sprintf( msgFmt, "UPDATE %s.%s SET UltimoId = UltimoId + 1 " "WHERE NombreTbl = \'%s\'", se->schemaName, se->tableCounterName, te->tableName ); returnCode = SQLPrepare( te->hstmt, msgFmt, SQL_NTS ); CHECK_HANDLE( SQL_HANDLE_STMT, te->hstmt, returnCode ); if( returnCode != SQL_SUCCESS ) return returnCode; } returnCode = SQLExecute( te->hstmt ); CHECK_HANDLE( SQL_HANDLE_STMT, te->hstmt, returnCode ); return returnCode; } ------------------------------------------------------------------------------------------------------------------------------------------
My problem is that I
want to prepare the statement only one twice in a global variable
from the first thread that required its value. The first thread that use this
function update the table without problems, but the second and the rest, the
SQLExecute fails with a machine error in module SQLCLI.
I think that SQLAllocHandle reserves memory in the
head of the first thread that uses this function, the handle is global but the
memory reserved around this handle is thread-private.
I'd like to somebody confirm me this
idea.
Of course, the function
called is between a mutex lock.
I'm working in a V4R4
version.
Regards
Adolfo Lopez
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