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POmultiple mysql_real_query() in while loop
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  1. POmultiple mysql_real_query() in while loop
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    copied!<p>It seems that when I have one mysql_real_query() function in a continuous while loop, the query will get executed OK.</p> <p>However, if multiple mysql_real_query() are inside the while loop, one right after the other. Depending on the query, sometimes neither the first query nor second query will execute properly.</p> <p>This seems like a threading issue to me. I'm wondering if the mysql c api has a way of dealing with this? Does anyone know how to deal with this? mysql_free_result() doesn't work since I am not even storing the results.</p> <pre><code>//keep polling as long as stop character '-' is not read while(szRxChar != '-') { // Check if a read is outstanding if (HasOverlappedIoCompleted(&amp;ovRead)) { // Issue a serial port read if (!ReadFile(hSerial,&amp;szRxChar,1, &amp;dwBytesRead,&amp;ovRead)) { DWORD dwErr = GetLastError(); if (dwErr!=ERROR_IO_PENDING) return dwErr; } } // Wait 5 seconds for serial input if (!(HasOverlappedIoCompleted(&amp;ovRead))) { WaitForSingleObject(hReadEvent,RESET_TIME); } // Check if serial input has arrived if (GetOverlappedResult(hSerial,&amp;ovRead, &amp;dwBytesRead,FALSE)) { // Wait for the write GetOverlappedResult(hSerial,&amp;ovWrite, &amp;dwBytesWritten,TRUE); //load tagBuffer with byte stream tagBuffer[i] = szRxChar; i++; tagBuffer[i] = 0; //char arrays are \0 terminated //run query with tagBuffer if( strlen(tagBuffer)==PACKET_LENGTH ) { sprintf(query,"insert into scan (rfidnum) values ('"); strcat(query, tagBuffer); strcat(query, "')"); mysql_real_query(&amp;mysql,query,(unsigned int)strlen(query)); i=0; } mysql_real_query(&amp;mysql,"insert into scan (rfidnum) values ('2nd query')",(unsigned int)strlen("insert into scan (rfid) values ('2nd query')")); mysql_free_result(res); } } </code></pre>
 

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