The GetLastError() function returns the last error code. The Error code constants are defined in the stderror.mqh file.
To print text messages use the ErrorDescription() function defined in the stdlib.mqh file.
The following table lists the Error codes returned from the trade server
ERR_NO_ERROR
0
No error returned.
ERR_NO_RESULT
1
No error returned, but the result is unknown.
ERR_COMMON_ERROR
2
Common error.
ERR_INVALID_TRADE_PARAMETERS
3
Invalid trade parameters.
ERR_SERVER_BUSY
4
Trade server is busy.
ERR_OLD_VERSION
5
Old version of the client terminal.
ERR_NO_CONNECTION
6
No connection with trade server.
ERR_NOT_ENOUGH_RIGHTS
7
Not enough rights.
ERR_TOO_FREQUENT_REQUESTS
8
Too frequent requests.
ERR_MALFUNCTIONAL_TRADE
9
Malfunctional trade operation.
ERR_ACCOUNT_DISABLED
64
Account disabled.
ERR_INVALID_ACCOUNT
65
Invalid account.
ERR_TRADE_TIMEOUT
128
Trade timeout.
ERR_INVALID_PRICE
129
Invalid price.
ERR_INVALID_STOPS
130
Invalid stops.
ERR_INVALID_TRADE_VOLUME
131
Invalid trade volume.
ERR_MARKET_CLOSED
132
Market is closed.
ERR_TRADE_DISABLED
133
Trade is disabled.
ERR_NOT_ENOUGH_MONEY
134
Not enough money.
ERR_PRICE_CHANGED
135
Price changed.
ERR_OFF_QUOTES
136
Off quotes.
ERR_BROKER_BUSY
137
Broker is busy.
ERR_REQUOTE
138
Requote.
ERR_ORDER_LOCKED
139
Order is locked.
ERR_LONG_POSITIONS_ONLY_ALLOWED
140
Long positions only allowed.
ERR_TOO_MANY_REQUESTS
141
Too many requests.
ERR_TRADE_MODIFY_DENIED
145
Modification denied because order too close to market.
ERR_TRADE_CONTEXT_BUSY
146
Trade context is busy.
MQL4 run time error codes
ERR_NO_MQLERROR
4000
No error.
ERR_WRONG_FUNCTION_POINTER
4001
Wrong function pointer.
ERR_ARRAY_INDEX_OUT_OF_RANGE
4002
Array index is out of range.
ERR_NO_MEMORY_FOR_FUNCTION_CALL_STACK
4003
No memory for function call stack.
ERR_RECURSIVE_STACK_OVERFLOW
4004
Recursive stack overflow.
ERR_NOT_ENOUGH_STACK_FOR_PARAMETER
4005
Not enough stack for parameter.
ERR_NO_MEMORY_FOR_PARAMETER_STRING
4006
No memory for parameter string.
ERR_NO_MEMORY_FOR_TEMP_STRING
4007
No memory for temp string.
ERR_NOT_INITIALIZED_STRING
4008
Not initialized string.
ERR_NOT_INITIALIZED_ARRAYSTRING
4009
Not initialized string in array.
ERR_NO_MEMORY_FOR_ARRAYSTRING
4010
No memory for array string.
ERR_TOO_LONG_STRING
4011
Too long string.
ERR_REMAINDER_FROM_ZERO_DIVIDE
4012
Remainder from zero divide.
ERR_ZERO_DIVIDE
4013
Zero divide.
ERR_UNKNOWN_COMMAND
4014
Unknown command.
ERR_WRONG_JUMP
4015
Wrong jump (never generated error).
ERR_NOT_INITIALIZED_ARRAY
4016
Not initialized array.
ERR_DLL_CALLS_NOT_ALLOWED
4017
DLL calls are not allowed.
ERR_CANNOT_LOAD_LIBRARY
4018
Cannot load library.
ERR_CANNOT_CALL_FUNCTION
4019
Cannot call function.
ERR_EXTERNAL_EXPERT_CALLS_NOT_ALLOWED
4020
Expert function calls are not allowed.
ERR_NOT_ENOUGH_MEMORY_FOR_RETURNED_STRING
4021
Not enough memory for temp string returned from function.
ERR_SYSTEM_BUSY
4022
System is busy (never generated error).
ERR_INVALID_FUNCTION_PARAMETERS_COUNT
4050
Invalid function parameters count.
ERR_INVALID_FUNCTION_PARAMETER_VALUE
4051
Invalid function parameter value.
ERR_STRING_FUNCTION_INTERNAL_ERROR
4052
String function internal error.
ERR_SOME_ARRAY_ERROR
4053
Some array error.
ERR_INCORRECT_SERIES_ARRAY_USING
4054
Incorrect series array using.
ERR_CUSTOM_INDICATOR_ERROR
4055
Custom indicator error.
ERR_INCOMPATIBLE_ARRAYS
4056
Arrays are incompatible.
ERR_GLOBAL_VARIABLES_PROCESSING_ERROR
4057
Global variables processing error.
ERR_GLOBAL_VARIABLE_NOT_FOUND
4058
Global variable not found.
ERR_FUNCTION_NOT_ALLOWED_IN_TESTING_MODE
4059
Function is not allowed in testing mode.
ERR_FUNCTION_NOT_CONFIRMED
4060
Function is not confirmed.
ERR_SEND_MAIL_ERROR
4061
Send mail error.
ERR_STRING_PARAMETER_EXPECTED
4062
String parameter expected.
ERR_INTEGER_PARAMETER_EXPECTED
4063
Integer parameter expected.
ERR_DOUBLE_PARAMETER_EXPECTED
4064
Double parameter expected.
ERR_ARRAY_AS_PARAMETER_EXPECTED
4065
Array as parameter expected.
ERR_HISTORY_WILL_UPDATED
4066
Requested history data in updating state.
ERR_END_OF_FILE
4099
End of file.
ERR_SOME_FILE_ERROR
4100
Some file error.
ERR_WRONG_FILE_NAME
4101
Wrong file name.
ERR_TOO_MANY_OPENED_FILES
4102
Too many opened files.
ERR_CANNOT_OPEN_FILE
4103
Cannot open file.
ERR_INCOMPATIBLE_ACCESS_TO_FILE
4104
Incompatible access to a file.
ERR_NO_ORDER_SELECTED
4105
No order selected.
ERR_UNKNOWN_SYMBOL
4106
Unknown symbol.
ERR_INVALID_PRICE_PARAM
4107
Invalid price.
ERR_INVALID_TICKET
4108
Invalid ticket.
ERR_TRADE_NOT_ALLOWED
4109
Trade is not allowed.
ERR_LONGS__NOT_ALLOWED
4110
Longs are not allowed.
ERR_SHORTS_NOT_ALLOWED
4111
Shorts are not allowed.
ERR_OBJECT_ALREADY_EXISTS
4200
Object exists already.
ERR_UNKNOWN_OBJECT_PROPERTY
4201
Unknown object property.
ERR_OBJECT_DOES_NOT_EXIST
4202
Object does not exist.
ERR_UNKNOWN_OBJECT_TYPE
4203
Unknown object type.
ERR_NO_OBJECT_NAME
4204
No object name.
ERR_OBJECT_COORDINATES_ERROR
4205
Object coordinates error.
ERR_NO_SPECIFIED_SUBWINDOW
4206
No specified subwindow
