Clang Flag: -Wdeprecated / -Wno-deprecated

The Clang compiler flags -Wdeprecated and -Wno-deprecated pertain to the emission of warnings related to deprecated features in source code. Deprecated features can include types, functions, variables, and more, that are marked as deprecated because they may be removed in future versions of a software or because their use is discouraged for other reasons. The use of these flags helps developers maintain modern and clean codebases by encouraging the migration away from deprecated features. -Wdeprecated is used to enable warnings about the usage of deprecated features. For some warnings, this flag is not active by default and needs to be explicitly enabled to warn about specific deprecated features. These include deprecated copying behaviors due to user-declared or user-provided copy constructors or destructors, the use of dynamic exception specifications, certain deprecated literal operators, and some specific cases of static data member initialization. -Wno-deprecated inversely suppresses warnings about the use of deprecated features that are enabled by default. This is useful in scenarios where maintaining backward compatibility or dealing with legacy codebases necessitates the use of deprecated features, or when the warnings are deemed not critical for the specific context of the project. Both flags are valuable tools in a developer’s arsenal for writing up-to-date, standard-compliant code, and managing the transition away from deprecated language or library features with minimal disruption.

AI Generated

Subroups

• -Wdeprecated-anon-enum-enum-conversion (1 element)
• -Wdeprecated-array-compare (1 element)
• -Wdeprecated-attributes (3 elements)
• -Wdeprecated-comma-subscript (1 element)
• -Wdeprecated-copy (2 elements)
• -Wdeprecated-copy-with-dtor (2 elements)
• -Wdeprecated-declarations (6 elements)
• -Wdeprecated-dynamic-exception-spec (1 element)
• -Wdeprecated-enum-compare (1 element)
• -Wdeprecated-enum-compare-conditional (1 element)
• -Wdeprecated-enum-enum-conversion (1 element)
• -Wdeprecated-enum-float-conversion (1 element)
• -Wdeprecated-builtins (1 element)
• -Wdeprecated-increment-bool (1 element)
• -Wdeprecated-literal-operator (1 element)
• -Wdeprecated-pragma (1 element)
• -Wdeprecated-register (1 element)
• -Wdeprecated-this-capture (1 element)
• -Wdeprecated-type (1 element)
• -Wdeprecated-volatile (5 elements)
• -Wdeprecated-writable-strings (1 element)
• -Wdeprecated-redundant-constexpr-static-def (1 element)

Warnings/Remarks

Default Active (Deactivate with -Wno-deprecated)

warn_O4_is_O3	warning: -O4 is equivalent to -O3
warn_access_decl_deprecated	warning: access declarations are deprecated; use using declarations instead
warn_drv_deprecated_arg	warning: argument 'A' is deprecated, use 'B' instead
warn_drv_treating_input_as_cxx	warning: treating 'A' input as 'B' when in C++ mode, this behavior is deprecated
warn_omp_depend_in_ordered_deprecated	warning: 'depend' clause for 'ordered' is deprecated; use 'doacross' instead
warn_omp_minus_in_reduction_deprecated	warning: minus(-) operator for reductions is deprecated; use + or user defined reduction instead
warn_option_invalid_ocl_version	warning: A does not support the option 'B'
warn_vector_long_decl_spec_combination	warning: Use of 'long' with '__vector' is deprecated
warn_arith_conv_mixed_anon_enum_types_cxx20	warning: arithmetic between bitwise operation between comparison of conditional expression between compound assignment of different enumeration types (B and C)   is deprecated
warn_depr_array_comparison	warning: comparison between two arrays is deprecated; to compare array addresses, use unary '+' to decay operands to pointers
warn_deprecated_noreturn_spelling	warning: the '_Noreturn' attribute spelling is deprecated in C2x; use 'noreturn' instead
warn_type_attribute_deprecated_on_decl	warning: applying attribute A to a declaration is deprecated; apply it to the type instead
warn_vector_mode_deprecated	warning: specifying vector types with the 'mode' attribute is deprecated; use the 'vector_size' attribute instead
warn_deprecated_comma_subscript	warning: top-level comma expression in array subscript is deprecated in C++20 and unsupported in C++23
warn_atl_uuid_deprecated	warning: specifying 'uuid' as an ATL attribute is deprecated; use __declspec instead
warn_cstyle_param	warning: use of C-style parameters in Objective-C method declarations is deprecated
warn_deprecated	warning: A is deprecated
warn_deprecated_fwdclass_message	warning: A may be deprecated because the receiver type is unknown
warn_deprecated_message	warning: A is deprecated: B
warn_property_method_deprecated	warning: property access is using A method which is deprecated
warn_comparison_mixed_enum_types_cxx20	warning: arithmetic between bitwise operation between comparison of conditional expression between compound assignment of different enumeration types (B and C)   is deprecated
warn_conditional_mixed_enum_types_cxx20	warning: arithmetic between bitwise operation between comparison of conditional expression between compound assignment of different enumeration types (B and C)   is deprecated
warn_arith_conv_mixed_enum_types_cxx20	warning: arithmetic between bitwise operation between comparison of conditional expression between compound assignment of different enumeration types (B and C)   is deprecated
warn_arith_conv_enum_float_cxx20	warning: arithmetic between bitwise operation between comparison of conditional expression between compound assignment of floating-point enumeration type C with from and enumeration floating-point type D is deprecated
warn_deprecated_builtin	warning: builtin A is deprecated; use B instead
warn_increment_bool	warning: incrementing expression of type bool is deprecated and incompatible with C++17
warn_pragma_deprecated_macro_use	warning: macro A has been marked as deprecated   : C
warn_deprecated_register	warning: 'register' storage class specifier is deprecated and incompatible with C++17
warn_deprecated_this_capture	warning: implicit capture of 'this' with a capture default of '=' is deprecated
warn_ext_int_deprecated	warning: '_ExtInt' is deprecated; use '_BitInt' instead
warn_deprecated_increment_decrement_volatile	warning: decrement increment of object of volatile-qualified type B is deprecated
warn_deprecated_simple_assign_volatile	warning: use of result of assignment to object of volatile-qualified type A is deprecated
warn_deprecated_volatile_param	warning: volatile-qualified parameter type A is deprecated
warn_deprecated_volatile_return	warning: volatile-qualified return type A is deprecated
warn_deprecated_volatile_structured_binding	warning: volatile qualifier in structured binding declaration is deprecated
warn_deprecated_string_literal_conversion	warning: conversion from string literal to A is deprecated

Default Inactive (Activate with -Wdeprecated)

warn_deprecated_copy	warning: definition of implicit copy constructor assignment operator for A is deprecated because it has a user-declared copy assignment operator constructor
warn_deprecated_copy_with_user_provided_copy	warning: definition of implicit copy constructor assignment operator for A is deprecated because it has a user-provided copy assignment operator constructor
warn_deprecated_copy_with_dtor	warning: definition of implicit copy constructor assignment operator for A is deprecated because it has a user-declared destructor
warn_deprecated_copy_with_user_provided_dtor	warning: definition of implicit copy constructor assignment operator for A is deprecated because it has a user-provided destructor
warn_exception_spec_deprecated	warning: dynamic exception specifications are deprecated
warn_deprecated_literal_operator_id	warning: identifier A preceded by whitespace in a literal operator declaration is deprecated
warn_deprecated_redundant_constexpr_static_def	warning: out-of-line definition of constexpr static data member is redundant in C++17 and is deprecated