Compiler Warnings C4600 Through C4799

 

For the latest documentation on Visual Studio 2017, see Visual Studio 2017 Documentation.

For the latest documentation on Visual Studio 2017, see Compiler Warnings C4600 Through C4799 on docs.microsoft.com. The articles in this part of the documentation contain information about a subset of the Visual C++ compiler warnings. You can access the information here or, in the Output window in Visual Studio, you can select an error number and then press the F1 key.

WarningMessage
Compiler Warning (level 1) C4600#pragma 'macro name': expected a valid non-empty string
Compiler warning (level 1) C4602#pragma pop_macro: 'macro name' no previous #pragma push_macro for this identifier
Compiler warning (level 1) C4603'<identifier>': macro is not defined or definition is different after precompiled header use
Compiler Warning (level 1) C4606#pragma warning: 'warning number' ignored; Code Analysis warnings are not associated with warning levels
Compiler Warning (level 3) C4608'union_member' has already been initialized by another union member in the initializer list, 'union_member'
Compiler warning (level 3) C4609'%$S' derives from default interface '%$S' on type '%$S'. Use a different default interface for '%$S', or break the base/derived relationship.
Compiler Warning (level 4) C4610object 'class' can never be instantiated - user defined constructor required
Compiler Warning (level 4) C4611interaction between 'function' and C++ object destruction is non-portable
Compiler warning (level 1) C4612error in include filename
Compiler warning (level 1) C4613'%$S': class of segment cannot be changed
Compiler Warning (level 1) C4615#pragma warning: unknown user warning type
Compiler Warning (level 1) C4616#pragma warning: warning number 'number' not a valid compiler warning
Compiler Warning (level 1) C4618pragma parameters included an empty string; pragma ignored
Compiler Warning (level 3) C4619#pragma warning: there is no warning number 'number'
Compiler warning (level 1) C4620no postfix form of 'operator ++' found for type 'type', using prefix form
Compiler Warning (level 1) C4621no postfix form of 'operator --' found for type 'type', using prefix form
Compiler warning (level 3) C4622overwriting debug information formed during creation of the precompiled header in object file: 'file'
Compiler Warning (level 4) C4623'derived class': default constructor was implicitly defined as deleted because a base class default constructor is inaccessible or deleted
Compiler Warning (level 1) C4624'derived class': destructor was implicitly defined as deleted because a base class destructor is inaccessible or deleted
Compiler Warning (level 4) C4625'derived class': copy constructor was implicitly defined as deleted because a base class copy constructor is inaccessible or deleted
Compiler Warning (level 4) C4626'derived class': assignment operator was implicitly defined as deleted because a base class assignment operator is inaccessible or deleted
Compiler Warning (level 1) C4627'<identifier>': skipped when looking for precompiled header use
Compiler Warning (level 1) C4628digraphs not supported with -Ze. Character sequence 'digraph' not interpreted as alternate token for '%s'
Compiler warning (level 4) C4629digraph used, character sequence 'digraph' interpreted as token 'char' (insert a space between the two characters if this is not what you intended)
Compiler Warning (level 1) C4630'symbol': 'extern' storage-class specifier illegal on member definition
Compiler warning (level 2) C4631MSXML or XPath unavailable, XML document comments will not be processed. reason
Compiler Warning (level 1) C4632XML document comment: file - access denied: reason
Compiler Warning (level 3) C4633XML document comment target: error: reason
Compiler warning (level 4) C4634XML document comment target: cannot be applied: reason
Compiler warning (level 3) C4635XML document comment target: badly-formed XML: reason
Compiler warning (level 3) C4636XML document comment applied to construct: tag requires non-empty 'attribute' attribute.
Compiler warning (level 3 and level 4) C4637XML document comment target: <include> tag discarded. Reason
Compiler warning (level 3) C4638XML document comment target: reference to unknown symbol 'symbol'.
Compiler Warning (level 4) C4639MSXML error, XML document comments will not be processed. Reason
Compiler Warning (level 3) C4640'instance': construction of local static object is not thread-safe
Compiler Warning (level 3) C4641XML document comment has an ambiguous cross reference:
Compiler warning (level 3) C4645function declared with __declspec(noreturn) has a return statement
Compiler warning (level 3) C4646function declared with __declspec(noreturn) has non-void return type
Compiler Warning (level 1) C4650debugging information not in precompiled header; only global symbols from the header will be available
Compiler Warning (level 1) C4651'definition' specified for precompiled header but not for current compile
Compiler Warning (level 1) C4652compiler option 'option' inconsistent with precompiled header; current command-line option will override that defined in the precompiled header
Compiler Warning (level 2) C4653compiler option 'option' inconsistent with precompiled header; current command-line option ignored
Compiler warning (level 1) C4655'symbol': variable type is new since the latest build, or is defined differently elsewhere
Compiler Warning (level 1) C4656'symbol': data type is new or has changed since the latest build, or is defined differently elsewhere
Compiler warning (level 1) C4657expression involves a data type that is new since the latest build
Compiler warning (level 1) C4658'function': function prototype is new since the latest build, or is declared differently elsewhere
Compiler Warning (level 1) C4659#pragma 'pragma': use of reserved segment 'segment' has undefined behavior, use #pragma comment(linker, ...)
Compiler Warning (level 1) C4661'identifier': no suitable definition provided for explicit template instantiation request
Compiler warning (level 1) C4662explicit instantiation; template-class 'identifier1' has no definition from which to specialize 'identifier2'
Compiler Warning (level 1) C4667'function': no function template defined that matches forced instantiation
Compiler Warning (level 4) C4668'symbol' is not defined as a preprocessor macro, replacing with '0' for 'directive'
Compiler Warning (level 1) C4669'cast': unsafe conversion: 'class' is a managed type object
Compiler warning (level 4) C4670'identifier': this base class is inaccessible
Compiler warning (level 4) C4671'identifier': the copy constructor is inaccessible
Compiler warning (level 4) C4672'identifier1': ambiguous. First seen as 'identifier2'
Compiler Warning (level 4) C4673throwing 'identifier' the following types will not be considered at the catch site
Compiler warning (level 1) C4674'method' should be declared 'static' and have exactly one parameter
Compiler warning (level 4) C4676'%s': the destructor is inaccessible
Compiler Warning (level 1) C4677'function': signature of non-private member contains assembly private type 'private_type'
Compiler warning (level 1) C4678base class 'base_type' is less accessible than 'derived_type'
Compiler Warning (level 1) C4679'member': could not import member
Compiler Warning (level 4) C4680'class': coclass does not specify a default interface
Compiler warning (level 4) C4681'class': coclass does not specify a default interface that is an event source
Compiler warning (level 4) C4682'parameter': no directional parameter attribute specified, defaulting to [in]
Compiler Warning (level 1) C4683'function': event source has an 'out'-parameter; exercise caution when hooking multiple event handlers
Compiler Warning (level 1) C4684'attribute': WARNING!! attribute may cause invalid code generation: use with caution
Compiler warning (level 1) C4685expecting '> >' found '>>' when parsing template parameters
Compiler Warning (level 3) C4686'user-defined type': possible change in behavior, change in UDT return calling convention
Compiler Warning C4687'class': a sealed abstract class cannot implement an interface 'interface'
Compiler warning (level 1) C4688'constraint': constraint list contains assembly private type 'type'
Compiler warning (level 1) C4689'%c': unsupported character in #pragma detect_mismatch; #pragma ignored
Compiler warning (level 4) C4690[ emitidl( pop ) ]: more pops than pushes
Compiler Warning (level 1) C4691'type': type referenced was expected in unreferenced assembly 'file', type defined in current translation unit used instead
Compiler Warning (level 1) C4692'function': signature of non-private member contains assembly private native type 'native_type'
Compiler warning (level 1) C4693'class': a sealed abstract class cannot have any instance members 'instance member'
Compiler warning (level 1) C4694'class': a sealed abstract class cannot have a base-class 'base_class'
Compiler warning (level 1) C4695#pragma execution_character_set: 'character set' is not a supported argument: currently only 'UTF-8' is supported
Compiler warning (level 1) C4696/ZBvalue1 option out of range; assuming 'value2'
Compiler Warning (level 1 and level 4) C4700uninitialized local variable 'name' used
Compiler Warning (level 4) C4701potentially uninitialized local variable 'name' used
Compiler Warning (level 4) C4702unreachable code
Compiler Warning (level 4) C4703potentially uninitialized local pointer variable '%s' used
Compiler Warning (level 4) C4706assignment within conditional expression
Compiler Warning (level 4) C4709comma operator within array index expression
Compiler Warning (level 4) C4710'function': function not inlined
Compiler Warning (level 1) C4711function 'function' selected for automatic inline expansion
Compiler Warning (level 4) C4714function 'function' marked as __forceinline not inlined
Compiler Warning (level 1) C4715'function': not all control paths return a value
Compiler Warning (level 1) C4716'function': must return a value
Compiler Warning (level 1) C4717'function': recursive on all control paths, function will cause runtime stack overflow
Compiler warning (level 4) C4718'function call': recursive call has no side effects, deleting
Compiler warning (level 1) C4719Double constant found when Qfast specified - use 'f' as a suffix to indicate single precision
Compiler warning (level 2) C4720in-line assembler reports: 'message'
Compiler warning (level 1) C4721'function': not available as an intrinsic
Compiler warning (level 1) C4722'function': destructor never returns, potential memory leak
Compiler Warning (level 3) C4723potential divide by 0
Compiler warning (level 3) C4724potential mod by 0
Compiler warning (level 3) C4725instruction may be inaccurate on some Pentiums
Compiler Warning (level 1) C4727PCH named pch_file with same timestamp found in obj_file_1 and obj_file_2. Using first PCH.
Compiler warning (level 1) C4728/Yl- option ignored because PCH reference is required
Compiler warning (level 4) C4729function too big for flow graph based warnings
Compiler Warning (Level 1) C4730Compiler warning (level 1) C4730'main': mixing _m64 and floating point expressions may result in incorrect code
Compiler Warning (Level 1) C4731'pointer': frame pointer register 'register' modified by inline assembly code
Compiler warning (level 1) C4732intrinsic '%s' is not supported in this architecture
Compiler Warning (Level 1) C4733Inline asm assigning to 'FS:0': handler not registered as safe handler
Compiler Warning (Level 3) C4738storing 32-bit float result in memory, possible loss of performance
Compiler warning (level 1) C4739reference to variable 'var' exceeds its storage space
Compiler Warning (Level 4) C4740flow in or out of inline asm code suppresses global optimization
Compiler Warning (Level 1) C4742'var' has different alignment in 'file1' and 'file2': number and number
Compiler Warning (Level 1) C4743'type' has different size in 'file1' and 'file2': number and number bytes
Compiler Warning (Level 1) C4744'var' has different type in 'file1' and 'file2': 'type1' and 'type2'
Compiler Warning C4746volatile access of '%s' is subject to /volatile:<iso|ms> setting; consider using __iso_volatile_load/store intrinsic functions
Compiler Warning (level 1) C4747Calling managed 'entrypoint': Managed code may not be run under loader lock, including the DLL entrypoint and calls reached from the DLL entrypoint
Compiler warning (level 1) C4750'identifier': function with _alloca() inlined into a loop
Compiler warning (level 4) C4751/arch:AVX does not apply to Intel(R) Streaming SIMD Extensions that are within inline ASM
Compiler warning (level 4) C4752found Intel(R) Advanced Vector Extensions; consider using /arch:AVX
Compiler warning (level 4) C4754Conversion rules for arithmetic operations in the comparison at %s(%d) mean that one branch cannot be executed. Cast '%s' to '%s' (or similar type of %d bytes).
Compiler warning C4755Conversion rules for arithmetic operations in the comparison at %s(%d) mean that one branch cannot be executed in an inlined function. Cast '%s' to '%s' (or similar type of %d bytes).
Compiler Warning (level 2) C4756overflow in constant arithmetic
Compiler warning (level 4) C4757subscript is a large unsigned value, did you intend a negative constant?
Compiler warning (level 4) C4764Can not align catch objects to greater than 16 bytes
Compiler warning (level 4) C4767section name '%s' is longer than 8 characters and will be truncated by the linker
Compiler warning C4770partially validated enum '%s' used as index
Compiler Warning (level 1) C4772#import referenced a type from a missing type library; 'missing_type' used as a placeholder
Compiler Warning (Level 1) C4788'identifier': identifier was truncated to 'number' characters
Compiler Warning (Level 1) C4789buffer 'identifier' of size N bytes will be overrun; M bytes will be written starting at offset L
Compiler warning (level 2) C4792function '%s' declared using sysimport and referenced from native code; import library required to link
Compiler Warning (level 1 and 3) C4793'function': function compiled as native:\n\t'reason'
Compiler warning (level 1) C4794segment of thread local storage variable '%s' changed from '%s' to '%s'
Compiler Warning (level 1) C4799function 'function' has no EMMS instruction
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