Microsoft C/C++ compiler warnings C4400 through C4599
The articles in this section describe Microsoft C/C++ compiler warning messages C4400-C4599.
Important
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Note
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Warning messages
| Warning | Message |
|---|---|
| Compiler warning (level 1) C4600 | #pragma 'macro name': expected a valid non-empty string |
| Compiler warning (level 4) C4400 | 'type': const/volatile qualifiers on this type are not supported |
| Compiler warning (level 1) C4401 | 'bitfield': member is bit field |
| Compiler warning (level 1) C4402 | must use PTR operator |
| Compiler warning (level 1) C4403 | illegal PTR operator |
| Compiler warning (level 3) C4404 | period on directive ignored |
| Compiler warning (level 1) C4405 | 'identifier': identifier is reserved word |
| Compiler warning (level 1) C4406 | operand on directive ignored |
| Compiler warning (level 1) C4407 | cast between different pointer to member representations, compiler may generate incorrect code |
| Compiler warning (level 4) C4408 | anonymous 'struct|union' did not declare any data members |
| Compiler warning (level 1) C4409 | illegal instruction size |
| Compiler warning (level 1) C4410 | illegal size for operand |
| Compiler warning (level 1) C4411 | 'identifier': symbol resolves to displacement register |
| Compiler warning (level 2) C4412 | 'function': function signature contains type 'type'; C++ objects are unsafe to pass between pure code and mixed or native. |
| Compiler warning C4413 | 'classname::member': reference member is initialized to a temporary that doesn't persist after the constructor exits |
| Compiler warning (level 3) C4414 | 'function': short jump to function converted to near |
| Compiler warning (level 1) C4415 | duplicate __declspec(code_seg('name')) |
| Compiler warning (level 1) C4416 | __declspec(code_seg(...)) contains empty string: ignored |
| Compiler warning (level 1) C4417 | an explicit template instantiation cannot have __declspec(code_seg(...)): ignored |
| Compiler warning (level 1) C4418 | __declspec(code_seg(...)) ignored on an enum |
| Compiler warning (level 3) C4419 | 'symbol' has no effect when applied to private ref class 'class'. |
| Compiler warning (level 1) C4420 | 'checked_operator': operator not available, using 'operator' instead; run-time checking may be compromised |
| Compiler warning (level 3) C4421 | 'parameter': a reference parameter on a resumable function is potentially unsafe |
| Compiler warning (level 3) C4423 | 'std::bad_alloc': will be caught by class ('type') on line number |
| Compiler warning (level 3) C4424 | catch for 'type1' preceded by 'type2' on line number; unpredictable behavior may result if 'std::bad_alloc' is thrown |
| Compiler warning (level 1) C4425 | A SAL annotation cannot be applied to '...' |
| Compiler warning (level 1) C4426 | optimization flags changed after including header, may be due to #pragma optimize() |
| Compiler warning (level 1) C4427 | 'operator': overflow in constant division, undefined behavior |
| Compiler warning (level 4) C4429 | possible incomplete or improperly formed universal-character-name |
| Compiler warning (Error) C4430 | missing type specifier - int assumed. Note: C++ does not support default-int |
| Compiler warning (level 4) C4431 | missing type specifier - int assumed. Note: C no longer supports default-int |
| Compiler warning (level 4) C4434 | a static constructor must have private accessibility; changing to private access |
| Compiler warning (level 4) C4435 | 'derived_class': Object layout under /vd2 will change due to virtual base 'base_class' |
| Compiler warning (level 1) C4436 | dynamic_cast from virtual base 'base_class' to 'derived_class' in constructor or destructor could fail with partially-constructed object |
| Compiler warning (level 4) C4437 | dynamic_cast from virtual base 'base_class' to 'derived_class' could fail in some contexts |
| Compiler warning C4438 | 'function': cannot be called safely in /await:clrcompat mode. If 'function' calls into the CLR it may result in CLR head corruption |
| Compiler warning (Error) C4439 | 'function': function definition with a managed type in the signature must have a __clrcall calling convention |
| Compiler warning (level 1) C4440 | calling convention redefinition from 'calling_convention1' to 'calling_convenction2' ignored |
| Compiler warning (level 1) C4441 | calling convention of 'calling_convention1' ignored; 'calling_convention2' used instead |
| Compiler warning (level 1) C4442 | embedded null terminator in __annotation argument. Value will be truncated. |
| Compiler warning (level 1) C4443 | expected pragma parameter to be '0', '1', or '2' |
| Compiler warning (level 3) C4444 | 'identifier': top level '__unaligned' is not implemented in this context |
| Compiler warning (level 1) C4445 | 'function': in a 'WinRT|managed' type a virtual method cannot be private |
| Compiler warning (level 1) C4446 | 'type': cannot map member 'name1' into this type, due to conflict with the type name. The method was renamed to 'name2' |
| Compiler warning (level 1) C4447 | 'main' signature found without threading model. Consider using 'int main(Platform::Array<Platform::String^>^ args)'. |
| Compiler warning C4448 | 'type1' does not have a default interface specified in metadata. Picking: 'type2', which may fail at runtime. |
| Compiler warning C4449 | 'type' an unsealed type should be marked as '[WebHostHidden]' |
| Compiler warning C4450 | 'type1' should be marked as '[WebHostHidden]' because it derives from 'type2' |
| Compiler warning (level 4) C4451 | 'classname1::member': Usage of ref class 'classname2::member' inside this context can lead to invalid marshaling of object across contexts |
| Compiler warning (level 1) C4452 | 'identifier': public type cannot be at global scope. It must be in a namespace that is a child of the name of the output .winmd file. |
| Compiler warning (level 1) C4453 | 'type': A '[WebHostHidden]' type should not be used on the published surface of a public type that is not '[WebHostHidden]' |
| Compiler warning (level 1) C4454 | 'function' is overloaded by more than the number of input parameters without having [DefaultOverload] specified. Picking 'declaration' as the default overload |
| Compiler warning (level 1) C4455 | 'operator operator': literal suffix identifiers that do not start with an underscore are reserved |
| Compiler warning (level 4) C4456 | declaration of 'identifier' hides previous local declaration |
| Compiler warning (level 4) C4457 | declaration of 'identifier' hides function parameter |
| Compiler warning (level 4) C4458 | declaration of 'identifier' hides class member |
| Compiler warning (level 4) C4459 | declaration of 'identifier' hides global declaration |
| Compiler warning (level 4) C4460 | 'WinRT|managed' operator 'operator', has parameter passed by reference. 'WinRT|managed' operator 'operator' has different semantics from C++ operator 'cpp_operator', did you intend to pass by value? |
| Compiler warning (level 1) C4461 | 'classname': this class has a finalizer '!finalizer' but no destructor '~dtor' |
| Compiler warning (level 1, Error) C4462 | 'type' : cannot determine the GUID of the type. Program may fail at runtime. |
| Compiler warning (level 4) C4463 | overflow; assigning 'value' to bit-field that can only hold values from 'min_value' to 'max_value' |
| Compiler warning (level 4) C4464 | relative include path contains '..' |
| Compiler warning C4466 | Could not perform coroutine heap elision |
| Compiler warning (level 1) C4467 | Usage of ATL attributes is deprecated |
| Compiler warning (level 1) C4468 | The [[fallthrough]] attribute must be followed by a case label or a default label |
| Compiler warning (level 1) C4470 | floating-point control pragmas ignored under /clr |
| Compiler warning (level 4) C4471 | 'enumeration': a forward declaration of an unscoped enumeration must have an underlying type (int assumed) |
| Compiler warning (level 1) C4472 | 'identifier' is a native enum: add an access specifier (private/public) to declare a 'WinRT|managed' enum |
| Compiler warning (level 1) C4473 | 'function' : not enough arguments passed for format string |
| Compiler warning (level 3) C4474 | 'function' : too many arguments passed for format string |
| Compiler warning (level 3) C4475 | 'function' : length modifier 'modifier' cannot be used with type field character 'character' in format specifier |
| Compiler warning (level 3) C4476 | 'function' : unknown type field character 'character' in format specifier |
| Compiler warning (level 1) C4477 | 'function' : format string 'string' requires an argument of type 'type', but variadic argument number has type 'type' |
| Compiler warning (level 1) C4478 | 'function' : positional and non-positional placeholders cannot be mixed in the same format string |
| Compiler warning (Error) C4480 | nonstandard extension used: specifying underlying type for enum 'enumeration' |
| Compiler warning (level 4) C4481 | nonstandard extension used: override specifier 'keyword' |
| Compiler warning C4482 | nonstandard extension used: enum 'enumeration' used in qualified name |
| Compiler warning (level 1, Error) C4483 | syntax error: expected C++ keyword |
| Compiler warning (Error) C4484 | 'override_function': matches base ref class method 'base_class_function', but is not marked 'virtual', 'new' or 'override'; 'new' (and not 'virtual') is assumed |
| Compiler warning (Error) C4485 | 'override_function': matches base ref class method 'base_class_function', but is not marked 'new' or 'override'; 'new' (and 'virtual') is assumed |
| Compiler warning (level 1) C4486 | 'function': a private virtual method of a ref class or value class should be marked 'sealed' |
| Compiler warning (level 4) C4487 | 'derived_class_function': matches inherited non-virtual method 'base_class_function' but is not explicitly marked 'new' |
| Compiler warning (level 1) C4488 | 'function': requires 'keyword' keyword to implement the interface method 'interface_method' |
| Compiler warning (level 1) C4489 | 'specifier': not allowed on interface method 'method'; override specifiers are only allowed on ref class and value class methods |
| Compiler warning (level 1) C4490 | 'override': incorrect use of override specifier; 'function' does not match a base ref class method |
| Compiler warning (level 1) C4491 | 'name': has an illegal IDL version format |
| Compiler warning (level 1, Error) C4492 | 'function1': matches base ref class method 'function2', but is not marked 'override' |
| Compiler warning (level 3, Error) C4493 | delete expression has no effect as the destructor of 'type' does not have 'public' accessibility |
| Compiler warning (level 1) C4494 | 'function' : Ignoring __declspec(allocator) because the function return type is not a pointer or reference |
| Compiler warning C4495 | nonstandard extension '__super' used: replace with explicit base class name |
| Compiler warning C4496 | nonstandard extension 'for each' used: replace with ranged-for statement |
| Compiler warning C4497 | nonstandard extension 'sealed' used: replace with 'final' |
| Compiler warning C4498 | nonstandard extension used: 'extension' |
| Compiler warning (level 4) C4499 | 'function' : an explicit specialization cannot have a storage class (ignored)" |
| Compiler warning (level 1) C4502 | 'linkage specification' requires use of keyword 'extern' and must precede all other specifiers |
| Compiler warning (level 1) C4503 | 'identifier': decorated name length exceeded, name was truncated |
| Compiler warning (level 4) C4505 | 'function': unreferenced local function has been removed |
| Compiler warning (level 1) C4506 | no definition for inline function 'function' |
| Compiler warning (level 1) C4508 | 'function': function should return a value; 'void' return type assumed |
| Compiler warning C4509 | nonstandard extension used: 'function' uses SEH and 'object' has destructor |
| Compiler warning (level 4) C4510 | 'class': default constructor was implicitly defined as deleted |
| Compiler warning (level 3) C4511 | 'class': copy constructor was implicitly defined as deleted |
| Compiler warning (level 4) C4512 | 'class': assignment operator was implicitly defined as deleted |
| Compiler warning (level 4) C4513 | 'class': destructor was implicitly defined as deleted |
| Compiler warning (level 4) C4514 | 'function': unreferenced inline function has been removed |
| Compiler warning (level 4) C4515 | 'namespace': namespace uses itself |
| Compiler warning (level 4) C4516 | 'class::symbol': access-declarations are deprecated; member using-declarations provide a better alternative |
| Compiler warning (level 4) C4517 | access-declarations are deprecated; member using-declarations provide a better alternative |
| Compiler warning (level 1) C4518 | 'specifier': storage-class or type specifier(s) unexpected here; ignored |
| Compiler warning (Error) C4519 | default template arguments are only allowed on a class template |
| Compiler warning (level 3) C4521 | 'class': multiple copy constructors specified |
| Compiler warning (level 3) C4522 | 'class': multiple assignment operators specified |
| Compiler warning (level 3) C4523 | 'class': multiple destructors specified |
| Compiler warning (level 1) C4526 | 'function': static member function cannot override virtual function 'virtual function' override ignored, virtual function will be hidden |
| Compiler warning (level 1) C4530 | C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc |
| Compiler warning (level 1) C4531 | C++ exception handling not available on Windows CE. Use Structured Exception Handling |
| Compiler warning (level 1) C4532 | 'continue': jump out of '__finally/finally' block has undefined behavior during termination handling |
| Compiler warning (level 1) C4533 | initialization of 'variable' is skipped by 'goto label' |
| Compiler warning (level 3) C4534 | 'constructor' will not be a default constructor for 'class/struct' 'identifier' due to the default argument |
| Compiler warning (level 3) C4535 | calling _set_se_translator() requires /EHa |
| Compiler warning (level 4) C4536 | 'typename': type-name exceeds meta-data limit of 'character_limit' characters |
| Compiler warning (level 1) C4537 | 'object': '.' applied to non-UDT type |
| Compiler warning (level 3) C4538 | 'type': const/volatile qualifiers on this type are not supported |
| Compiler warning (level 1) C4540 | dynamic_cast used to convert to inaccessible or ambiguous base; run-time test will fail ('type1' to 'type2') |
| Compiler warning (level 1) C4541 | 'identifier' used on polymorphic type 'type' with /GR-; unpredictable behavior may result |
| Compiler warning (level 1) C4542 | Skipping generation of merged injected text file, cannot write filetype file: 'issue': message |
| Compiler warning (level 3) C4543 | Injected text suppressed by attribute 'no_injected_text' |
| Compiler warning (level 1) C4544 | 'declaration': default template argument ignored on this template declaration |
| Compiler warning (level 1) C4545 | expression before comma evaluates to a function which is missing an argument list |
| Compiler warning (level 1) C4546 | function call before comma missing argument list |
| Compiler warning (level 1) C4547 | 'operator': operator before comma has no effect; expected operator with side-effect |
| Compiler warning (level 1) C4548 | expression before comma has no effect; expected expression with side-effect |
| Compiler warning (level 1) C4549 | 'operator': operator before comma has no effect; did you intend 'operator'? |
| Compiler warning (level 1) C4550 | expression evaluates to a function which is missing an argument list |
| Compiler warning (level 1) C4551 | function call missing argument list |
| Compiler warning (level 1) C4552 | 'operator': operator has no effect; expected operator with side-effect |
| Compiler warning (level 1) C4553 | 'operator': operator has no effect; did you intend 'operator'? |
| Compiler warning (level 3) C4554 C4554 | 'operator': check operator precedence for possible error; use parentheses to clarify precedence |
| Compiler warning (level 1) C4555 | expression has no effect; expected expression with side-effect |
| Compiler warning (level 1) C4556 | value of intrinsic immediate argument 'value' is out of range 'lower_bound - upper_bound' |
| Compiler warning (level 3) C4557 | '__assume' contains effect 'effect' |
| Compiler warning (level 1) C4558 | value of operand 'value' is out of range 'lower_bound - upper_bound' |
| Compiler warning (level 4) C4559 | 'function': redefinition; the function gains __declspec(modifier) |
| Compiler warning (level 1) C4561 | '__fastcall' incompatible with the '/clr' option: converting to '__stdcall' |
| Compiler warning (level 4) C4562 | fully prototyped functions are required with the '/clr' option: converting '()' to '(void)' |
| Compiler warning (level 4) C4564 | method 'method' of 'class' 'classname' defines unsupported default parameter 'parameter' |
| Compiler warning (level 4) C4565 | 'function': redefinition; the symbol was previously declared with __declspec(modifier) |
| Compiler warning (level 1) C4566 | character represented by universal-character-name 'char' cannot be represented in the current code page (number) |
| Compiler warning (level 1) C4568 | 'function': no members match the signature of the explicit override |
| Compiler warning (level 3) C4569 | 'function': no members match the signature of the explicit override |
| Compiler warning (level 3) C4570 | 'type': is not explicitly declared as abstract but has abstract functions |
| Compiler warning (level 4) C4571 | Informational: catch(...) semantics changed since Visual C++ 7.1; structured exceptions (SEH) are no longer caught |
| Compiler warning (level 1) C4572 | [ParamArray] attribute is deprecated under /clr, use '...' instead |
| Compiler warning (level 1) C4573 | the usage of 'lambda function' requires the compiler to capture 'this' but the current default capture mode does not allow it |
| Compiler warning (level 4) C4574 | 'Identifier' is defined to be '0': did you mean to use '#if identifier'? |
| Compiler warning (level 1) C4575 | '__vectorcall' incompatible with the '/clr' option: converting to '__stdcall' |
| Compiler warning (level 1, Error) C4576 | a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax |
| Compiler warning (level 1, Off) C4577 | 'noexcept' used with no exception handling mode specified; termination on exception is not guaranteed. Specify /EHsc |
| Compiler warning (level 1, Error) C4578 | 'abs': conversion from 'type1' to 'type2', possible loss of data (Did you mean to call 'function' or to #include <cmath>?) |
| Compiler warning (level 3) C4580 | [attribute] is deprecated; instead specify System::Attribute or Platform::Metadata as a base class |
| Compiler warning (level 1) C4581 | deprecated behavior: '"string"' replaced with 'string' to process attribute |
| Compiler warning (level 4) C4582 | 'type': constructor is not implicitly called |
| Compiler warning (level 4) C4583 | 'type': destructor is not implicitly called |
| Compiler warning (level 1) C4584 | 'class1': base-class 'class2' is already a base-class of 'class3' |
| Compiler warning (level 1, Error) C4585 | 'class': A WinRT 'public ref class' must either be sealed or derive from an existing unsealed class |
| Compiler warning (level 1, Error) C4586 | 'type': A public type cannot be declared in a top-level namespace called 'Windows' |
| Compiler warning (level 1) C4587 | 'anonymous_structure': behavior change: constructor is no longer implicitly called |
| Compiler warning (level 1) C4588 | 'anonymous_structure': behavior change: destructor is no longer implicitly called |
| Compiler warning (level 4) C4589 | Constructor of abstract class 'class1' ignores initializer for virtual base class 'class2' |
| Compiler warning (level 1) C4591 | 'constexpr' call-depth limit of number exceeded (/constexpr:depth<NUMBER>) |
| Compiler warning (level 3) C4592 | 'function': 'constexpr' call evaluation failed; function will be called at run-time |
| Compiler warning (level 1) C4593 | 'function': 'constexpr' call evaluation step limit of 'limit' exceeded; use /constexpr:steps<NUMBER> to increase the limit |
| Compiler warning (level 3) C4594 | 'type': destructor will not be implicitly called if an exception is thrown |
| Compiler warning (level 1) C4595 | 'type': behavior change: destructor will no longer be implicitly called if an exception is thrown |
| Compiler warning (level 4) C4596 | 'identifier': illegal qualified name in member declaration |
| Compiler warning (error) C4597 | undefined behavior: offsetof applied to a member of a virtual base |
| Compiler warning (level 1 and level 3) C4598 | '#include "header"': header number number in the precompiled header does not match current compilation at that position |
| Compiler warning (level 3) C4599 | 'flag path': command line argument number number does not match precompiled header |
See also
C/C++ Compiler and build tools errors and warnings
Compiler warnings C4000 - C5999