mysql call to libmysql.dll to get my app to automatically reconnect after mysql timeout - mysql

Question

I am using autohotkey to make mysql calls. The mysql interface was deciphered by referencing a visual basic api to mysql.
I am using the mysql connect calls referenced in this post: http://www.autohotkey.com/forum/viewtopic.php?t=12482
I would like to add a dllcall to replicate this perl call to mysql_options...
mysql_options(mysql, MYSQL_OPT_RECONNECT, &true);
It is my understanding that this call would enable my program to gracefully reconnect to mysql after the standard 8 hour mysql timeout. I want my application to remain up indefinitely.
Here is my code. A reference on googles source code libary suggests that the reconnect constant is 20. Everything works except the mysql_opt_reconnect call.
Can anyone help me determine the proper call to libmysql.dll to get my app to automatically reconnect after mysql timeout has occurred?
;============================================================
; mysql.ahk
;
; Provides a set of functions to connect and query a mysql database
;============================================================
FileInstall, libmysql.dll, %A_AppData%\libmysql.dll, 1
;============================================================
; Connect to mysql database and return db handle
;
; host = DTWRO-WS0061
; user = alan
; password = *******
; database = rush
;============================================================
dbConnect(host,user,password,database){
if (A_IsCompiled) {
ExternDir := A_AppData
} else {
ExternDir := A_WorkingDir
}
hModule := DllCall("LoadLibrary", "Str", ExternDir "\libmySQL.dll")
If (hModule = 0)
{
MsgBox 16, MySQL Error 233, Can't load libmySQL.dll from directory %ExternDir%
ExitApp
}
db := DllCall("libmySQL.dll\mysql_init", "UInt", 0)
If (db = 0)
{
MsgBox 16, MySQL Error 445, Not enough memory to connect to MySQL
ExitApp
}
; figure out how to turn on reconnect call!
; mysql_options(mysql, MYSQL_OPT_RECONNECT, &true);
value := DllCall("libmySQL.dll\mysql_options"
, "UInt", db
, "UInt", 20 ; is this the correct constant which represents MYSQL_OPT_RECONNECT?... see below
, "UInt", 1) ; true
connection := DllCall("libmySQL.dll\mysql_real_connect"
, "UInt", db
, "Str", host ; host name
, "Str", user ; user name
, "Str", password ; password
, "Str", database ; database name
, "UInt", 3306 ; port
, "UInt", 0 ; unix_socket
, "UInt", 0) ; client_flag
If (connection = 0)
{
HandleMySQLError(db, "Cannot connect to database")
Return
}
serverVersion := DllCall("libmySQL.dll\mysql_get_server_info", "UInt", db, "Str")
;MsgBox % "Ping database: " . DllCall("libmySQL.dll\mysql_ping", "UInt", db) . "`nServer version: " . serverVersion
return db
}
;============================================================
; mysql error handling
;============================================================
HandleMySQLError(db, message, query="") { ; the equal sign means optional
errorCode := DllCall("libmySQL.dll\mysql_errno", "UInt", db)
errorStr := DllCall("libmySQL.dll\mysql_error", "UInt", db, "Str")
MsgBox 16, MySQL Error: %message%, Error %errorCode%: %errorStr%`n`n%query%
Return
}
;============================================================
; mysql get address
;============================================================
GetUIntAtAddress(_addr, _offset)
{
local addr
addr := _addr + _offset * 4
Return *addr + (*(addr + 1) << 8) + (*(addr + 2) << 16) + (*(addr + 3) << 24)
}
;============================================================
; process query
;============================================================
dbQuery(_db, _query)
{
local resultString, result, requestResult, fieldCount
local row, lengths, length, fieldPointer, field
query4error := RegExReplace(_query , "\t", " ") ; convert tabs to spaces so error message formatting is legible
result := DllCall("libmySQL.dll\mysql_query", "UInt", _db , "Str", _query)
If (result != 0) {
errorMsg = %_query%
HandleMySQLError(_db, "dbQuery Fail", query4error)
Return
}
requestResult := DllCall("libmySQL.dll\mysql_store_result", "UInt", _db)
if (requestResult = 0) { ; call must have been an insert or delete ... a select would return results to pass back
return
}
fieldCount := DllCall("libmySQL.dll\mysql_num_fields", "UInt", requestResult)
Loop
{
row := DllCall("libmySQL.dll\mysql_fetch_row", "UInt", requestResult)
If (row = 0 || row == "")
Break
; Get a pointer on a table of lengths (unsigned long)
lengths := DllCall("libmySQL.dll\mysql_fetch_lengths" , "UInt", requestResult)
Loop %fieldCount%
{
length := GetUIntAtAddress(lengths, A_Index - 1)
fieldPointer := GetUIntAtAddress(row, A_Index - 1)
VarSetCapacity(field, length)
DllCall("lstrcpy", "Str", field, "UInt", fieldPointer)
resultString := resultString . field
If (A_Index < fieldCount)
resultString := resultString . "|" ; seperator for fields
}
resultString := resultString . "`n" ; seperator for records
}
; remove last newline from resultString
resultString := RegExReplace(resultString , "`n$", "")
Return resultString
}

Answer 1

It took me while to think outside the box, but I finally found a solution that works very well.
I simply added a settimer command to re-connect to the mysql database after 8 hours. 8 hours is the default database connection timeout.
Now the AHK app can remain running indefinitely and is always connected to the database!

Answer 2

Even better... I used an oop class to retain the mysql connection parameters, so that when the mysql connection timed out and a new mysql call is made, it can automatically reconnect.