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POMysql_num_rows() Segfaults
 

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    <p>I'm writing a program using C++ and the MySQL C API (version 5.1.31 ubuntu2). However, if the query is <em>UPDATE</em> then I get a <em>Segmentation Fault</em> error when executing the line "RowsReturned = mysql_num_rows( Result );".</p> <pre><code>//this code snippet contains only the relevant code MYSQL_RES *Result; long RowsReturned; MYSQL_RES *MYSQLDB::RunQuery( const char* Query ) { if( mysql_query( Connection, Query) ) { std::cout &lt;&lt; "Error: " &lt;&lt; mysql_error( Connection ); exit(1); } Result = mysql_store_result( Connection ); RowsReturned = mysql_num_rows( Result ); return Result; } </code></pre> <p>Compiled using g++ 4.3.3 (g++ test.cpp -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient_r -o Test)</p> <p>Thanks in advance.</p> <pre><code>//this snippet contains the entire class code class MYSQLDB { public: void Connect( const char* DB ); MYSQL_RES *RunQuery( const char* Query ); long NumRows(); void Close(); MYSQL_ROW GetRow(); private: MYSQL *Connection; MYSQL_RES *Result; MYSQL_ROW Row; long RowsReturned; }; void MYSQLDB::Connect( const char* DB ) { Connection = mysql_init( NULL ); if( Connection == NULL ) { std::cout &lt;&lt; "Error: " &lt;&lt; mysql_error( Connection ); exit( 1 ); } if ( mysql_real_connect( Connection, "localhost", "root", "password", DB, 0, NULL, 0 ) == NULL) { std::cout &lt;&lt; "Error: " &lt;&lt; mysql_error( Connection ); exit(1); } } MYSQL_RES *MYSQLDB::RunQuery( const char* Query ) { if( mysql_query( Connection, Query) ) { std::cout &lt;&lt; "Error: " &lt;&lt; mysql_error( Connection ); exit(1); } Result = mysql_store_result( Connection ); RowsReturned = (long)mysql_num_rows( Result ); //ERROR!!!!!!! return Result; } long MYSQLDB::NumRows() { return RowsReturned; } void MYSQLDB::Close() { mysql_free_result( Result ); mysql_close( Connection ); } MYSQL_ROW MYSQLDB::GetRow() { return mysql_fetch_row( Result ); } </code></pre>
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