The current MQL5 reference for PositionSelect states that “only one position
can exist for a symbol
at any moment of time”.
In fact, the
latest version of MT5 allows more than one position to be opened for a symbol at the same time.
grabbing the ticket number of each position as it is opened and storing them
for further use, how do I find out the ticket numbers for all the open
positions for a symbol?
The function returns the
ticket of a position with the specified index in the list of open
positions and automatically selects the position to work with using
functions PositionGetDouble, PositionGetInteger, PositionGetString.
[in] The index of a position in the list of open positions, numeration starts with 0.
The ticket of the position. Returns 0 if the function fails.
For the "netting" interpretation of positions (ACCOUNT_MARGIN_MODE_RETAIL_NETTING and ACCOUNT_MARGIN_MODE_EXCHANGE), only one position can exist for a symbol at any moment of time. This position is a result of one or more deals. Do not confuse positions with valid pending orders, which are also displayed on the Trading tab of the Toolbox window.
If individual positions are allowed (ACCOUNT_MARGIN_MODE_RETAIL_HEDGING), multiple positions can be open for one symbol.
To ensure receipt of fresh data about a position, it is recommended to call PositionSelect() right before referring to them.
PositionGetSymbol(), PositionSelect(), Position Properties