Delphi xe2's hidden hints and warnings options

There are a number of warnings available in Delphi xe2 that are not very well known ented. While you can control them in the Project Options dialog, and you can turn them on using {$ Warn} Directives or in command line compiler options, the documentation for the warning identifiers is currently pretty piecemeal, and there is no clear link between the project options, warning directive identifiers, and numeric identifiers.

The{$ Warn}Compiler Directive takes effect only in the unit it is in. it overrides Project Settings and command line compiler flags. to turn a warning on or off for a block of code (although you'll have to work hard to convince me that this is an acceptable solution 99% of the time ):

{$ Warn symbol_deprecated on} {$ warn symbol_deprecated off}

To restore the warning to its previous setting:

{$ Warn symbol_deprecated default}

And finally, you can convert a warning into an error:

{$ Warn symbol_deprecated error}

To change the setting in your project, go to project | options, Delphi compiler, hints and warnings, and expand the output warnings setting:

Delphi's Project Options dialog-hints and warnings

To change the setting in the command line compiler, use the-W flag, for example:

Dcc32-W + symbol_deprecated myproject. DPR
W-SYMBOL_DEPRECATED myproject. DPR

Or to turn the warning into an error:

Dcc32-w ^ symbol_deprecated myproject. DPR

Note, if you type this from the Windows command prompt, you will have to repeat the ^ symbol, as ^ is an escape symbol:

Dcc32-w ^ symbol_deprecated myproject. DPR

These are the hints and warning identifiers I am aware, along with what I understand are the default settings and numeric identifiers, and links to the relevant Help topics.

ID	Directive ID	Default	Description	Notes
W1000	Symbol_deprecated	Off	Symbol '% s' is deprecated (Delphi)
W1001	Symbol_library	Off	Symbol '% s' is specific to a library (Delphi)
W1002	Symbol_platform	Off	Symbol '% s' is specific to a platform (Delphi)
W1003	Symbol_experimental	On	Symbol '% s' is experimental (Delphi)
W1004	Unit_library	Off	Unit '% s' is specific to a library (Delphi)
W1005	Unit_platform	Off	Unit '% s' is specific to a platform (Delphi)
W1006	Unit_deprecated	Off	Unit '% s' is deprecated (Delphi)
W1007	Unit_experimental	On	Unit '% s' is experimental (Delphi)
W1008	Hresult_compat	On	Integer and hresult interchanged
W1009	Hiding_member	On	Redeclaration of '% s' hides a member in the base class (Delphi)
W1010	Hidden_virtual	On	Method '% s' hides virtual method of base type' % s' (Delphi)
W1011	Garbage	On	Text after final 'end. '-ignored by Compiler (Delphi)
W1012	Bounds_error	On	Constant expression violates subrange Bounds
W1013	Zero_nil_compat	On	Constant 0 converted to nil (Delphi)
W1014	String_const_trunced	On	String constant truncated to fit string % LD (Delphi)
W1015	For_loop_var_varpar	On	For-loop variable '% s' cannot be passed as VaR parameter (Delphi)
W1016	Typed_const_varpar	On	Typed constant '% s' passed as VaR parameter (Delphi)
W1017	Asg_to_typed_const	On	Assignment to typed constant '% s' (Delphi)
W1018	Case_label_range	On	Case label outside of range of case expression (Delphi)
X1019	For_variable	On	For loop control variable must be simple local variable (Delphi)
X1020	Constructing_abstract	On	Constructing instance of '% s' ining abstract method' % S. % s' (Delphi)
W1021	Comparison_false	On	Comparison always evaluates to false (Delphi)
W1022	Comparison_true	On	Comparison always evaluates to true (Delphi)
W1023	Comparing_signed_unsigned	On	Comparing signed and unsigned types-widened both operands (Delphi)
W1024	Combining_signed_unsigned	On	Combining signed and unsigned types-widened both operands (Delphi)
X1025	Unsupported_construct	On	Unsupported language feature: '% s' (Delphi)
X1026	File_open	On	File not found '% s' (Delphi)	Despite being listed as a warning, turning this off appears to have no effect.
F1027	File_open_unitsrc	On	Unit not found '% s' or binary equivalents (% s) (Delphi)
X1028	Bad_global_symbol	On	Bad global symbol definition '% s' in object file' % s' (Delphi)
W1029	Duplicate_ctor_dtor	On	Duplicate % s '% s' with identical parameters will be inacessible from C ++ (Delphi)
X1030	Invalid_directive	On	Invalid compiler directive-'% s' (Delphi)
W1031	Package_no_link	On	Package '% s' will not be written to disk because-J option is enabled (Delphi)
W1032	Packaged_threadvar	On	Exported package threadvar '% S. % s' cannot be used outside of this package (Delphi)
W1033	Implicit_import	On	Unit '% s' implicitly imported into package' % s' (Delphi)
W1034	Hppemit_ignored	On	$ Hppemit '% s' ignored (Delphi)
W1035	No_retval	On	Return Value of function '% s' might be undefined (Delphi)
W1036	Use_before_def	On	Variable '% s' might not have been initialized (Delphi)
W1037	For_loop_var_undef	On	For-loop variable '% s' may be undefined after loop (Delphi)
E1038	Unit_name_mismatch	On	Unit identifier '% s' does not match file name (Delphi)
W1039	No_pai_file_found	On	No configuration files found (Delphi)
W1040	Implicit_variants	On	Implicit use of variants unit (Delphi)
W1041	Unicode_to_locale	On	Error converting Unicode Char to locale charset. String truncated. Is your Lang environment variable set correctly (Delphi)
W1042	Locale_to_unicode	On	Error converting locale string '% s' to Unicode. String truncated. Is your Lang environment variable set correctly (Delphi)
W1043	Imagebase_multiple	On	Imagebase $ % x is not a multiple of 64 K. rounding down to $ % x (Delphi)
W1044	Suspicious_typecast	On	Suspicious typecast of % s to % s (Delphi)
W1045	Private_propaccessor	On	Property declaration references ancestor private '% S. % s' (Delphi)
W1046	Unsafe_type	Off	Unsafe type '% S % s' (Delphi)
W1047	Unsafe_code	Off	Unsafe code '% s' (Delphi)
W1048	Unsafe_cast	Off	Unsafe typecast of '% s' to' % s' (Delphi)
W1049	Option_truncated	On	Value '% s' for Option % s was truncated (Delphi)
W1050	Widechar_reduced	On	Widechar sorted CED to byte char in set expressions (Delphi)
W1051	Duplicates_ignored	On	Duplicate Symbol names in namespace. Using '% S. % s' found in % S. Ignoring duplicate in % s (Delphi)
W1052	Unit_init_seq	On	Can't find system. runtime. compilerservices. runclassconstructor. Unit initialization order will not follow uses clause order	Does not seem to be encoded ented in xe2
W1053	Local_pinvoke	On	Local pinvoke Code has not been made because external routine '% s' in package' % s' is defined using package local types in its Custom Attributes	Does not seem to be encoded ented in xe2
X1054	Message_directive	On	% S (Delphi)	User-Defined warning messages (see below). Turns Off message hints as well but not message errors.
W1055	Typeinfo_implicitly_added	On	Published caused rtti ($ m +) to be added to type '% s' (Delphi)
X1056	Rlink_warning	On	Duplicate Resource Type % s, Id % s; file % s resource kept; file % s resource discarded (Delphi)
W1057	Implicit_string_cast	On	Implicit string cast from '% s' to' % s' (Delphi)
W1058	Implicit_string_cast_loss	On	Implicit string cast with potential data loss from '% s' to' % s' (Delphi)
W1059	Explicit_string_cast	Off	Explicit string cast from '% s' to' % s' (Delphi)
W1060	Explicit_string_cast_loss	Off	Explicit string cast with potential data loss from '% s' to' % s' (Delphi)
W1061	Cvt_wchar_to_achar	On	W1061 narrowing given widechar constant ('% s') to ansichar lost information (Delphi)
W1062	Cvt_narrowing_string_lost	On	Narrowing given wide String constant lost information (Delphi)
W1063	Cvt_achar_to_wchar	On	Widening given ansichar constant ('% s') to widechar lost information (Delphi)
W1064	Cvt_widening_string_lost	On	Widening given ansistring constant lost information (Delphi)
W1066	Non_portable_typecast	On	Lost Extended Floating Point precision. Ced CED to double (Delphi)
W1201	Xml_whitespace_not_allowed	On	XML comment on '% s' has badly formed XML-' whitespace is not allowed at this location. '(Delphi)
W1202	Xml_unknown_entity	On	XML comment on '% s' has badly formed XML-'reference to undefined entity' % s (Delphi)
W1203	Xml_invalid_name_start	On	XML comment on '% s' has badly formed XML-'a name was started with an invalid character.' (Delphi)
W1204	Xml_invalid_name	On	XML comment on '% s' has badly formed XML-'a name contained an invalid character.' (Delphi)
W1205	Xml_expected_character	On	XML comment on '% s' has badly formed XML-'the character' % C' was expected. '(Delphi)
W1206	Xml_cref_no_resolve	On	XML comment on '% s' has CREF attribute' % s' that cocould not be resolved (Delphi)
W1207	Xml_no_parm	On	XML comment on '% s' has a Param tag for' % s', but there is no parameter by that name (Delphi)
W1208	Xml_no_matching_parm	On	Parameter '% s' has no matching Param tag in the XML comment for' % s' (but other parameters do) (Delphi)

The$ MessageDirective allows generationH1054,W1054,E1054AndF1054Messages. User-Defined hint and warning messages can be turned off{$ Warn message_directive off}But logically enough, user-defined error and fatal messages can not be disabled. For example, add the following line to myunit. PAS:

{$ Message warn 'this is a user warning '}

Which will gives a compiler warning similar to the following:

[DCC Warning] myunit. PAS (25): w1054 this is a user warning

Finally, I'm not going to discuss$ WarningsDirective, doesn t to say that I don't think it's ever necessary or sensible to turn it off. if you must turn a warning off for a specific section of code, turn just that warning off as discussed above. using{$ Warnings off}Is just as unhelpful as an emptyExceptBlock.