Hi All, Inspired by which is a very good work, I introduce my first UDF and also my first Post in this forum. ParallelProc.zip I focus on simplicity of the library usage: _PPInitialize($iMaximumThreadQueue = 10, $iSlaveSpawnDelay = 0) _PPExecute($sFunction, $vParameter, $iArrayCount = 0) _PPDeinitialize() With just the 3 functions, you guys can build a parallel processing program. The UDF uses socket programming and a environment variable for Master process to communicate to Slave process. Another functionality, it supports passing Array variables from Master to Slave To do: - Passing back value from Slave to Master - Pause and Resume Slave process Looking forward for comments and inputs Example: Example.zip