Detecting new bar / candle

Take a look at the MQL5=>MQL4 conversion functions listed here. Time[0] doesn't exist, but iTime() is listed in mt4timeseries_2

I've always used Bars rather than Time[0], but the principle is exactly the same. The following code in OnTick() will set m_bNewBar true for one tick. This assumes that the code is in a class method and m_bNewBar and m_nLastBars are class members. Alternatively, they could be declared globally, C-fashion.

int nBars=Bars(Symbol(),PERIOD_CURRENT);

if(m_nLastBars!=nBars){m_nLastBars=nBars;m_bNewBar=true;}

else

{m_bNewBar=false;}