MQL5 ReferenceConstants, Enumerations and StructuresCodes of Errors and WarningsRuntime Errors

Runtime Errors

GetLastError() is the function that returns the last error code that is stored in the predefined variable _LastError. This value can be reset to zero by the ResetLastError() function.

Constant	Code	Description
ERR_SUCCESS	0	The operation completed successfully
ERR_INTERNAL_ERROR	4001	Unexpected internal error
ERR_WRONG_INTERNAL_PARAMETER	4002	Wrong parameter in the inner call of the client terminal function
ERR_INVALID_PARAMETER	4003	Wrong parameter when calling the system function
ERR_NOT_ENOUGH_MEMORY	4004	Not enough memory to perform the system function
ERR_STRUCT_WITHOBJECTS_ORCLASS	4005	The structure contains objects of strings and/or dynamic arrays and/or structure of such objects and/or classes
ERR_INVALID_ARRAY	4006	Array of a wrong type, wrong size, or a damaged object of a dynamic array
ERR_ARRAY_RESIZE_ERROR	4007	Not enough memory for the relocation of an array, or an attempt to change the size of a static array
ERR_STRING_RESIZE_ERROR	4008	Not enough memory for the relocation of string
ERR_NOTINITIALIZED_STRING	4009	Not initialized string
ERR_INVALID_DATETIME	4010	Invalid date and/or time
ERR_ARRAY_BAD_SIZE	4011	Total amount of elements in the array cannot exceed 2147483647
ERR_INVALID_POINTER	4012	Wrong pointer
ERR_INVALID_POINTER_TYPE	4013	Wrong type of pointer
ERR_FUNCTION_NOT_ALLOWED	4014	Function is not allowed for call
ERR_RESOURCE_NAME_DUPLICATED	4015	The names of the dynamic and the static resource match
ERR_RESOURCE_NOT_FOUND	4016	Resource with this name has not been found in EX5
ERR_RESOURCE_UNSUPPORTED_TYPE	4017	Unsupported resource type or its size exceeds 16 Mb
ERR_RESOURCE_NAME_IS_TOO_LONG	4018	The resource name exceeds 63 characters
ERR_MATH_OVERFLOW	4019	Overflow occurred when calculating math function
ERR_SLEEP_ERROR	4020	Out of test end date after calling Sleep()
ERR_PROGRAM_STOPPED	4022	Test forcibly stopped from the outside. For example, optimization interrupted, visual testing window closed or testing agent stopped
ERR_INVALID_TYPE	4023	Invalid type
ERR_INVALID_HANDLE	4024	Invalid handle
ERR_TOO_MANY_OBJECTS	4025	Object pool filled out
Charts
ERR_CHART_WRONG_ID	4101	Wrong chart ID
ERR_CHART_NO_REPLY	4102	Chart does not respond
ERR_CHART_NOT_FOUND	4103	Chart not found
ERR_CHART_NO_EXPERT	4104	No Expert Advisor in the chart that could handle the event
ERR_CHART_CANNOT_OPEN	4105	Chart opening error
ERR_CHART_CANNOT_CHANGE	4106	Failed to change chart symbol and period
ERR_CHART_WRONG_PARAMETER	4107	Error value of the parameter for the function of working with charts
ERR_CHART_CANNOT_CREATE_TIMER	4108	Failed to create timer
ERR_CHART_WRONG_PROPERTY	4109	Wrong chart property ID
ERR_CHART_SCREENSHOT_FAILED	4110	Error creating screenshots
ERR_CHART_NAVIGATE_FAILED	4111	Error navigating through chart
ERR_CHART_TEMPLATE_FAILED	4112	Error applying template
ERR_CHART_WINDOW_NOT_FOUND	4113	Subwindow containing the indicator was not found
ERR_CHART_INDICATOR_CANNOT_ADD	4114	Error adding an indicator to chart
ERR_CHART_INDICATOR_CANNOT_DEL	4115	Error deleting an indicator from the chart
ERR_CHART_INDICATOR_NOT_FOUND	4116	Indicator not found on the specified chart
Graphical Objects
ERR_OBJECT_ERROR	4201	Error working with a graphical object
ERR_OBJECT_NOT_FOUND	4202	Graphical object was not found
ERR_OBJECT_WRONG_PROPERTY	4203	Wrong ID of a graphical object property
ERR_OBJECT_GETDATE_FAILED	4204	Unable to get date corresponding to the value
ERR_OBJECT_GETVALUE_FAILED	4205	Unable to get value corresponding to the date
MarketInfo
ERR_MARKET_UNKNOWN_SYMBOL	4301	Unknown symbol
ERR_MARKET_NOT_SELECTED	4302	Symbol is not selected in MarketWatch
ERR_MARKET_WRONG_PROPERTY	4303	Wrong identifier of a symbol property
ERR_MARKET_LASTTIME_UNKNOWN	4304	Time of the last tick is not known (no ticks)
ERR_MARKET_SELECT_ERROR	4305	Error adding or deleting a symbol in MarketWatch
History Access
ERR_HISTORY_NOT_FOUND	4401	Requested history not found
ERR_HISTORY_WRONG_PROPERTY	4402	Wrong ID of the history property
ERR_HISTORY_TIMEOUT	4403	Exceeded history request timeout
ERR_HISTORY_BARS_LIMIT	4404	Number of requested bars limited by terminal settings
ERR_HISTORY_LOAD_ERRORS	4405	Multiple errors when loading history
ERR_HISTORY_SMALL_BUFFER	4407	Receiving array is too small to store all requested data
Global_Variables
ERR_GLOBALVARIABLE_NOT_FOUND	4501	Global variable of the client terminal is not found
ERR_GLOBALVARIABLE_EXISTS	4502	Global variable of the client terminal with the same name already exists
ERR_GLOBALVARIABLE_NOT_MODIFIED	4503	Global variables were not modified
ERR_GLOBALVARIABLE_CANNOTREAD	4504	Cannot read file with global variable values
ERR_GLOBALVARIABLE_CANNOTWRITE	4505	Cannot write file with global variable values
ERR_MAIL_SEND_FAILED	4510	Email sending failed
ERR_PLAY_SOUND_FAILED	4511	Sound playing failed
ERR_MQL5_WRONG_PROPERTY	4512	Wrong identifier of the program property
ERR_TERMINAL_WRONG_PROPERTY	4513	Wrong identifier of the terminal property
ERR_FTP_SEND_FAILED	4514	File sending via ftp failed
ERR_NOTIFICATION_SEND_FAILED	4515	Failed to send a notification
ERR_NOTIFICATION_WRONG_PARAMETER	4516	Invalid parameter for sending a notification – an empty string or NULL has been passed to the SendNotification() function
ERR_NOTIFICATION_WRONG_SETTINGS	4517	Wrong settings of notifications in the terminal (ID is not specified or permission is not set)
ERR_NOTIFICATION_TOO_FREQUENT	4518	Too frequent sending of notifications
ERR_FTP_NOSERVER	4519	FTP server is not specified
ERR_FTP_NOLOGIN	4520	FTP login is not specified
ERR_FTP_FILE_ERROR	4521	File not found in the MQL5\Files directory to send on FTP server
ERR_FTP_CONNECT_FAILED	4522	FTP connection failed
ERR_FTP_CHANGEDIR	4523	FTP path not found on server
Custom Indicator Buffers
ERR_BUFFERS_NO_MEMORY	4601	Not enough memory for the distribution of indicator buffers
ERR_BUFFERS_WRONG_INDEX	4602	Wrong indicator buffer index
Custom Indicator Properties
ERR_CUSTOM_WRONG_PROPERTY	4603	Wrong ID of the custom indicator property
Account
ERR_ACCOUNT_WRONG_PROPERTY	4701	Wrong account property ID
ERR_TRADE_WRONG_PROPERTY	4751	Wrong trade property ID
ERR_TRADE_DISABLED	4752	Trading by Expert Advisors prohibited
ERR_TRADE_POSITION_NOT_FOUND	4753	Position not found
ERR_TRADE_ORDER_NOT_FOUND	4754	Order not found
ERR_TRADE_DEAL_NOT_FOUND	4755	Deal not found
ERR_TRADE_SEND_FAILED	4756	Trade request sending failed
ERR_TRADE_CALC_FAILED	4758	Failed to calculate profit or margin
Indicators
ERR_INDICATOR_UNKNOWN_SYMBOL	4801	Unknown symbol
ERR_INDICATOR_CANNOT_CREATE	4802	Indicator cannot be created
ERR_INDICATOR_NO_MEMORY	4803	Not enough memory to add the indicator
ERR_INDICATOR_CANNOT_APPLY	4804	The indicator cannot be applied to another indicator
ERR_INDICATOR_CANNOT_ADD	4805	Error applying an indicator to chart
ERR_INDICATOR_DATA_NOT_FOUND	4806	Requested data not found
ERR_INDICATOR_WRONG_HANDLE	4807	Wrong indicator handle
ERR_INDICATOR_WRONG_PARAMETERS	4808	Wrong number of parameters when creating an indicator
ERR_INDICATOR_PARAMETERS_MISSING	4809	No parameters when creating an indicator
ERR_INDICATOR_CUSTOM_NAME	4810	The first parameter in the array must be the name of the custom indicator
ERR_INDICATOR_PARAMETER_TYPE	4811	Invalid parameter type in the array when creating an indicator
ERR_INDICATOR_WRONG_INDEX	4812	Wrong index of the requested indicator buffer
Depth of Market
ERR_BOOKS_CANNOT_ADD	4901	Depth Of Market can not be added
ERR_BOOKS_CANNOT_DELETE	4902	Depth Of Market can not be removed
ERR_BOOKS_CANNOT_GET	4903	The data from Depth Of Market can not be obtained
ERR_BOOKS_CANNOT_SUBSCRIBE	4904	Error in subscribing to receive new data from Depth Of Market
File Operations
ERR_TOO_MANY_FILES	5001	More than 64 files cannot be opened at the same time
ERR_WRONG_FILENAME	5002	Invalid file name
ERR_TOO_LONG_FILENAME	5003	Too long file name
ERR_CANNOT_OPEN_FILE	5004	File opening error
ERR_FILE_CACHEBUFFER_ERROR	5005	Not enough memory for cache to read
ERR_CANNOT_DELETE_FILE	5006	File deleting error
ERR_INVALID_FILEHANDLE	5007	A file with this handle was closed, or was not opening at all
ERR_WRONG_FILEHANDLE	5008	Wrong file handle
ERR_FILE_NOTTOWRITE	5009	The file must be opened for writing
ERR_FILE_NOTTOREAD	5010	The file must be opened for reading
ERR_FILE_NOTBIN	5011	The file must be opened as a binary one
ERR_FILE_NOTTXT	5012	The file must be opened as a text
ERR_FILE_NOTTXTORCSV	5013	The file must be opened as a text or CSV
ERR_FILE_NOTCSV	5014	The file must be opened as CSV
ERR_FILE_READERROR	5015	File reading error
ERR_FILE_BINSTRINGSIZE	5016	String size must be specified, because the file is opened as binary
ERR_INCOMPATIBLE_FILE	5017	A text file must be for string arrays, for other arrays - binary
ERR_FILE_IS_DIRECTORY	5018	This is not a file, this is a directory
ERR_FILE_NOT_EXIST	5019	File does not exist
ERR_FILE_CANNOT_REWRITE	5020	File can not be rewritten
ERR_WRONG_DIRECTORYNAME	5021	Wrong directory name
ERR_DIRECTORY_NOT_EXIST	5022	Directory does not exist
ERR_FILE_ISNOT_DIRECTORY	5023	This is a file, not a directory
ERR_CANNOT_DELETE_DIRECTORY	5024	The directory cannot be removed
ERR_CANNOT_CLEAN_DIRECTORY	5025	Failed to clear the directory (probably one or more files are blocked and removal operation failed)
ERR_FILE_WRITEERROR	5026	Failed to write a resource to a file
ERR_FILE_ENDOFFILE	5027	Unable to read the next piece of data from a CSV file (FileReadString, FileReadNumber, FileReadDatetime, FileReadBool), since the end of file is reached
String Casting
ERR_NO_STRING_DATE	5030	No date in the string
ERR_WRONG_STRING_DATE	5031	Wrong date in the string
ERR_WRONG_STRING_TIME	5032	Wrong time in the string
ERR_STRING_TIME_ERROR	5033	Error converting string to date
ERR_STRING_OUT_OF_MEMORY	5034	Not enough memory for the string
ERR_STRING_SMALL_LEN	5035	The string length is less than expected
ERR_STRING_TOO_BIGNUMBER	5036	Too large number, more than ULONG_MAX
ERR_WRONG_FORMATSTRING	5037	Invalid format string
ERR_TOO_MANY_FORMATTERS	5038	Amount of format specifiers more than the parameters
ERR_TOO_MANY_PARAMETERS	5039	Amount of parameters more than the format specifiers
ERR_WRONG_STRING_PARAMETER	5040	Damaged parameter of string type
ERR_STRINGPOS_OUTOFRANGE	5041	Position outside the string
ERR_STRING_ZEROADDED	5042	0 added to the string end, a useless operation
ERR_STRING_UNKNOWNTYPE	5043	Unknown data type when converting to a string
ERR_WRONG_STRING_OBJECT	5044	Damaged string object
Operations with Arrays
ERR_INCOMPATIBLE_ARRAYS	5050	Copying incompatible arrays. String array can be copied only to a string array, and a numeric array - in numeric array only
ERR_SMALL_ASSERIES_ARRAY	5051	The receiving array is declared as AS_SERIES, and it is of insufficient size
ERR_SMALL_ARRAY	5052	Too small array, the starting position is outside the array
ERR_ZEROSIZE_ARRAY	5053	An array of zero length
ERR_NUMBER_ARRAYS_ONLY	5054	Must be a numeric array
ERR_ONEDIM_ARRAYS_ONLY	5055	Must be a one-dimensional array
ERR_SERIES_ARRAY	5056	Timeseries cannot be used
ERR_DOUBLE_ARRAY_ONLY	5057	Must be an array of type double
ERR_FLOAT_ARRAY_ONLY	5058	Must be an array of type float
ERR_LONG_ARRAY_ONLY	5059	Must be an array of type long
ERR_INT_ARRAY_ONLY	5060	Must be an array of type int
ERR_SHORT_ARRAY_ONLY	5061	Must be an array of type short
ERR_CHAR_ARRAY_ONLY	5062	Must be an array of type char
ERR_STRING_ARRAY_ONLY	5063	String array only
Operations with OpenCL
ERR_OPENCL_NOT_SUPPORTED	5100	OpenCL functions are not supported on this computer
ERR_OPENCL_INTERNAL	5101	Internal error occurred when running OpenCL
ERR_OPENCL_INVALID_HANDLE	5102	Invalid OpenCL handle
ERR_OPENCL_CONTEXT_CREATE	5103	Error creating the OpenCL context
ERR_OPENCL_QUEUE_CREATE	5104	Failed to create a run queue in OpenCL
ERR_OPENCL_PROGRAM_CREATE	5105	Error occurred when compiling an OpenCL program
ERR_OPENCL_TOO_LONG_KERNEL_NAME	5106	Too long kernel name (OpenCL kernel)
ERR_OPENCL_KERNEL_CREATE	5107	Error creating an OpenCL kernel
ERR_OPENCL_SET_KERNEL_PARAMETER	5108	Error occurred when setting parameters for the OpenCL kernel
ERR_OPENCL_EXECUTE	5109	OpenCL program runtime error
ERR_OPENCL_WRONG_BUFFER_SIZE	5110	Invalid size of the OpenCL buffer
ERR_OPENCL_WRONG_BUFFER_OFFSET	5111	Invalid offset in the OpenCL buffer
ERR_OPENCL_BUFFER_CREATE	5112	Failed to create an OpenCL buffer
ERR_OPENCL_TOO_MANY_OBJECTS	5113	Too many OpenCL objects
ERR_OPENCL_SELECTDEVICE	5114	OpenCL device selection error
Working with databases
ERR_DATABASE_INTERNAL	5120	Internal database error
ERR_DATABASE_INVALID_HANDLE	5121	Invalid database handle
ERR_DATABASE_TOO_MANY_OBJECTS	5122	Exceeded the maximum acceptable number of Database objects
ERR_DATABASE_CONNECT	5123	Database connection error
ERR_DATABASE_EXECUTE	5124	Request execution error
ERR_DATABASE_PREPARE	5125	Request generation error
ERR_DATABASE_NO_MORE_DATA	5126	No more data to read
ERR_DATABASE_STEP	5127	Failed to move to the next request entry
ERR_DATABASE_NOT_READY	5128	Data for reading request results are not ready yet
ERR_DATABASE_BIND_PARAMETERS	5129	Failed to auto substitute parameters to an SQL request
Operations with WebRequest
ERR_WEBREQUEST_INVALID_ADDRESS	5200	Invalid URL
ERR_WEBREQUEST_CONNECT_FAILED	5201	Failed to connect to specified URL
ERR_WEBREQUEST_TIMEOUT	5202	Timeout exceeded
ERR_WEBREQUEST_REQUEST_FAILED	5203	HTTP request failed
Operations with network (sockets)
ERR_NETSOCKET_INVALIDHANDLE	5270	Invalid socket handle passed to function
ERR_NETSOCKET_TOO_MANY_OPENED	5271	Too many open sockets (max 128)
ERR_NETSOCKET_CANNOT_CONNECT	5272	Failed to connect to remote host
ERR_NETSOCKET_IO_ERROR	5273	Failed to send/receive data from socket
ERR_NETSOCKET_HANDSHAKE_FAILED	5274	Failed to establish secure connection (TLS Handshake)
ERR_NETSOCKET_NO_CERTIFICATE	5275	No data on certificate protecting the connection
Custom Symbols
ERR_NOT_CUSTOM_SYMBOL	5300	A custom symbol must be specified
ERR_CUSTOM_SYMBOL_WRONG_NAME	5301	The name of the custom symbol is invalid. The symbol name can only contain Latin letters without punctuation, spaces or special characters (may only contain ".", "_", "&" and "#"). It is not recommended to use characters <, >, :, ", /,\, \|, ?, *.
ERR_CUSTOM_SYMBOL_NAME_LONG	5302	The name of the custom symbol is too long. The length of the symbol name must not exceed 32 characters including the ending 0 character
ERR_CUSTOM_SYMBOL_PATH_LONG	5303	The path of the custom symbol is too long. The path length should not exceed 128 characters including "Custom\\", the symbol name, group separators and the ending 0
ERR_CUSTOM_SYMBOL_EXIST	5304	A custom symbol with the same name already exists
ERR_CUSTOM_SYMBOL_ERROR	5305	Error occurred while creating, deleting or changing the custom symbol
ERR_CUSTOM_SYMBOL_SELECTED	5306	You are trying to delete a custom symbol selected in Market Watch
ERR_CUSTOM_SYMBOL_PROPERTY_WRONG	5307	An invalid custom symbol property
ERR_CUSTOM_SYMBOL_PARAMETER_ERROR	5308	A wrong parameter while setting the property of a custom symbol
ERR_CUSTOM_SYMBOL_PARAMETER_LONG	5309	A too long string parameter while setting the property of a custom symbol
ERR_CUSTOM_TICKS_WRONG_ORDER	5310	Ticks in the array are not arranged in the order of time
Economic Calendar
ERR_CALENDAR_MORE_DATA	5400	Array size is insufficient for receiving descriptions of all values
ERR_CALENDAR_TIMEOUT	5401	Request time limit exceeded
ERR_CALENDAR_NO_DATA	5402	Country is not found
Working with databases
ERR_DATABASE_ERROR	5601	Generic error
ERR_DATABASE_LOGIC	5602	SQLite internal logic error
ERR_DATABASE_PERM	5603	Access denied
ERR_DATABASE_ABORT	5604	Callback routine requested abort
ERR_DATABASE_BUSY	5605	Database file locked
ERR_DATABASE_LOCKED	5606	Database table locked
ERR_DATABASE_NOMEM	5607	Insufficient memory for completing operation
ERR_DATABASE_READONLY	5608	Attempt to write to readonly database
ERR_DATABASE_INTERRUPT	5609	Operation terminated by sqlite3_interrupt()
ERR_DATABASE_IOERR	5610	Disk I/O error
ERR_DATABASE_CORRUPT	5611	Database disk image corrupted
ERR_DATABASE_NOTFOUND	5612	Unknown operation code in sqlite3_file_control()
ERR_DATABASE_FULL	5613	Insertion failed because database is full
ERR_DATABASE_CANTOPEN	5614	Unable to open the database file
ERR_DATABASE_PROTOCOL	5615	Database lock protocol error
ERR_DATABASE_EMPTY	5616	Internal use only
ERR_DATABASE_SCHEMA	5617	Database schema changed
ERR_DATABASE_TOOBIG	5618	String or BLOB exceeds size limit
ERR_DATABASE_CONSTRAINT	5619	Abort due to constraint violation
ERR_DATABASE_MISMATCH	5620	Data type mismatch
ERR_DATABASE_MISUSE	5621	Library used incorrectly
ERR_DATABASE_NOLFS	5622	Uses OS features not supported on host
ERR_DATABASE_AUTH	5623	Authorization denied
ERR_DATABASE_FORMAT	5624	Not used
ERR_DATABASE_RANGE	5625	Bind parameter error, incorrect index
ERR_DATABASE_NOTADB	5626	File opened that is not database file
Matrix and Vector Methods
ERR_MATRIX_INTERNAL	5700	Internal error of the matrix/vector executing subsystem
ERR_MATRIX_NOT_INITIALIZED	5701	Matrix/vector not initialized
ERR_MATRIX_INCONSISTENT	5702	Inconsistent size of matrices/vectors in operation
ERR_MATRIX_INVALID_SIZE	5703	Invalid matrix/vector size
ERR_MATRIX_INVALID_TYPE	5704	Invalid matrix/vector type
ERR_MATRIX_FUNC_NOT_ALLOWED	5705	Function not available for this matrix/vector
ERR_MATRIX_CONTAINS_NAN	5706	Matrix/vector contains non-numbers (Nan/Inf)
ONNX models
ERR_ONNX_INTERNAL	5800	ONNX internal error
ERR_ONNX_NOT_INITIALIZED	5801	ONNX Runtime API initialization error
ERR_ONNX_NOT_SUPPORTED	5802	Property or value not supported by MQL5
ERR_ONNX_RUN_FAILED	5803	ONNX runtime API run error
ERR_ONNX_INVALID_PARAMETERS_COUNT	5804	Invalid number of parameters passed to OnnxRun
ERR_ONNX_INVALID_PARAMETER	5805	Invalid parameter value
ERR_ONNX_INVALID_PARAMETER_TYPE	5806	Invalid parameter type
ERR_ONNX_INVALID_PARAMETER_SIZE	5807	Invalid parameter size
ERR_ONNX_WRONG_DIMENSION	5808	Tensor dimension not set or invalid
User errors
ERR_USER_ERROR_FIRST	65536	User defined errors start with this code