MT5 · code and request checks
MQL5 Bid undeclared identifier: read a quote explicitly
My MT5 Bid example failed compilation with 1 error and could send 0 orders, so check your price interface first.
Arnold Holm · 2026-10-22
What the error means
A trader asked how to declare Bid in a trading program. The example also used an MT4-style order call. Those are two separate problems. Adding a variable called Bid can silence one name error while leaving the rest of the program wrong. I isolated the name error in a two-line original script. The native MT5 compiler rejected Print(Bid). A second script declares a MqlTick structure and calls SymbolInfoTick for the requested symbol. That source compiled. Neither script was executed and neither submits a trade. I check the target language before replacing price names. A source file compiled as MQL5 needs the MQL5 price interface. The official SymbolInfoTick reference returns prices and the time of the last quote through a structure, with a boolean success result. My reader checks that result, then rejects a missing timestamp or a non-positive bid. These checks are a chosen defensive policy, not a claim that the resulting quote is recent enough for your strategy. Compilation answers whether these declarations and calls are accepted. It does not answer whether the symbol exists at your broker, whether the terminal is connected, or whether the quote belongs to the intended decision time. Those checks still need a controlled demo run. Preserve the exact symbol name, including its broker suffix, rather than quietly substituting a similar market.
Three code paths to check
1. An MT4 price name was copied into an MT5 source.
Read the source extension and the compiler log together. Fix the language interface before touching entry, stop or target rules.
2. An empty local variable was mistaken for a market price.
A declaration creates storage. It does not fetch a quote. Keep retrieval success separate from the price value you intend to use.
3. A compile result was treated as a trading result.
A program can compile while reading the wrong symbol or an old quote. Add explicit runtime cases before connecting an execution path.
An explicit reader with no trading path
On 22 October 2026 I compiled both original files with the installed MetaEditor. BidNegative.mq5 produced error 256 for the undeclared name Bid. BidReader.mq5 produced zero errors and zero warnings. The log image below is rendered from those compiler results. It is not a terminal screenshot or a quote read. The compiled script has an OnStart entry point that only prints a label. I did not run it. TryBid is not called by that entry point. This proof establishes the compiler boundary and the availability of the declared interface, with no observed market price or execution result.
bool TryBid(const string symbol,double &price)
{
MqlTick quote={};
if(!SymbolInfoTick(symbol,quote) || quote.time_msc<=0 || quote.bid<=0) return false;
price=quote.bid;
return true;
}Compile-only proof. No runtime call, fresh-quote check, symbol availability check, order submission, fill or repair of the forum author's complete program.
How you know it is fixed
Check the name in its actual language
Compile your smallest failing source with its intended compiler. Keep the exact error line before editing.
Keep unsuccessful reads separate
In a later demo test, an unsuccessful quote read must prevent the trading decision. A zero-initialized structure is not a market price.
Your five-minute source check
Find the failing Bid reference. Compare it with the MQL5 SymbolInfoTick declaration. Write down the exact symbol and the maximum quote age your own rule accepts.
Your own source
Find the next line to check
Start with the free EA-Check. Your code stays in your browser. It highlights patterns with line numbers; it does not prove the broker accepts an order.
Want one small change shown on your own case?
DEMO0: send the problem and try a free compiled demo first. R49: one authorised, reproducible MT4/MT5 defect in readable source up to 500 lines, with three agreed cases. 49 USD fixed. Delivery within 48 hours after source review and funding. The exact case is agreed before funded work.
Send the expected and actual behaviourRelated checks
Common questions
Does this prove a valid current bid was read?
No. The reader compiled but was not executed. Quote availability and age remain runtime checks.
Does declaring Bid fix an MT4-style OrderSend call?
No. Price retrieval and the trading function interface are separate changes. Check both against the actual target language.
Sources and limits
These public questions explain the error; use your own EA log to check whether the same cause applies.