Compiler Warnings Dialog Box
Use the Compiler Warnings dialog box to customize the warnings LabWindows/CVI displays in the Build Output window. You can select a predefined warning level that contains a group of specific warnings or you can use the checkboxes to select individual warnings manually.
The Compiler Warnings dialog box contains the following options:
- Warning level—Sets the warning level for the compiler warnings that appear in the Build Output window. Select from the following warning levels:
- None—Displays no warnings.
- Common—Displays the warnings labeled as Common.
- Extended—Displays the warnings labeled as Common and Extended.
- All—Displays the warnings labeled as Common, Extended, and All.
When you add or remove warnings from a warning level, LabWindows/CVI places an asterisk (*) next to the warning level label to indicate this modification.
If you open a project saved in LabWindows/CVI 2012 or earlier, LabWindows/CVI automatically selects the warnings for the project that correspond to the LabWindows/CVI 2012 and earlier settings. - Warning selection table—Displays the warnings, the default level with which the warning is associated, and whether the individual warning has been added to a different warning level or removed from its default warning level. You can right-click in the selection table and select from the following context menu options:
- Find—Invokes the Find dialog box.
- Show warning flags/Show warning names—Toggles between displaying the warning flags the compiler uses or displaying the easy-to-read warning names.
- Sort by level—Sorts the warnings according to the level with which they are associated.
- Sort by status—Sorts the warnings according to their status of Added or Removed.
- Sort by state—Sorts the warnings by their state of selected or unselected.
- Sort alphabetically—Sorts the warnings alphabetically.
- Warning description—Displays a description of the warning type.
- Code example—Displays example code that demonstrates the warning.
The following table displays the warning name, warning flag, associated warning level, and description for the warnings you can choose to display or hide in the Build Output window.
| Warning Name | Warning Flag | Warning Level | Warning Description |
|---|---|---|---|
| Array bounds | -Warray-bounds | Common | Warn if an array is accessed out of bounds. |
| Assign enum | -Wassign-enum | Common | Warn if an enum variable is assigned a value that is not covered by the enum. |
| Char initialization | -Wchar-init | Common | Warn if an improper char array initialization is detected. |
| Covered switch default | -Wcovered-switch-default | Common | Warn if a switch that covers all values of an enum has a default case. |
| Disabled macro expansion | -Wdisabled-macro-expansion | Common | Warn about recursive macros, for which expansion is disabled. |
| Division by zero | -Wdivision-by-zero | Common | Warn if division by zero is detected. |
| Duplicate declaration specifier | -Wduplicate-decl-specifier | Common | Warn if a declaration contains a duplicate type specifier. |
| Ignored qualifiers | -Wignored-qualifiers | Common | Warn if the type qualifier of a return type is ignored. |
| Integer precision loss | -Wint-conversion | Common | Warn about precision loss in conversions involving integer numbers. This warning is especially useful for porting code to 64-bit. |
| Invalid return | -Winvalid-return | Common | Warn when return statements return values for void functions. This warning turns into an error when C99 extensions are enabled. |
| Invalid source encoding | -Winvalid-source-encoding | Common | Warn about illegal character encoding in character or string literals. |
| KnR promoted parameter compatibility | -Wknr-promoted-parameter | Common | Warn if a promoted old-style function parameter is not compatible with the parameter type of the previous function declaration. |
| Loop analysis | -Wloop-analysis | Common | Warn if variable(s) used in loop condition are not modified in loop body. |
| Missing return value | -Wmissing-return-value | Common | Warn when the return statement is missing the value for non-void functions. |
| Null dereference | -Wnull-dereference | Common | Warn if a null pointer is dereferenced. |
| OpenMP: nested parallel | -Womp-nested-parallel | Common | Warn if a nested parallel construct is ignored. OpenMP support and C99 extensions must be enabled to receive this warning. |
| OpenMP: repeated ordered | -Womp-repeated-ordered | Common | Warn if multiple ordered regions are detected in a loop iteration. OpenMP support and C99 extensions must be enabled to receive this warning. |
| Panel handle | -Wpanel-handle | Common | Warn if a constant expression is used as a panel handle. |
| Parentheses | -Wparentheses | Common | Warn if operators are mixed in a way that suggests that a problem can occur due to operator precendence, which can be resolved by the use of parentheses. |
| Pointer conversions | -Wpointer-conv | Common | Detect incompatible conversions involving pointers. |
| Pointer sign | -Wpointer-sign | Common | Warn if a signed/unsigned pointer mismatch is detected. |
| Pointer to int conversions | -Wpointer-int-conv | Common | Detect incompatible conversions involving pointers and integers. |
| Return type | -Wreturn-type | Common | Warn if a non-void function does not have a return type. |
| Sequence point | -Wsequence-point | Common | Warn about a sequencing ambiguity within an expression. |
| Sizeof array argument | -Wsizeof-array-argument | Common | Warn about possible unintended usage of sizeof applied to an array function parameter. |
| Sizeof array decay | -Wsizeof-array-decay | Common | Warn about possible unintended usage of sizeof applied to pointer arithmetic on an array variable. |
| strncat size | -Wstrncat-size | Common | Warn about wrong values passed to size argument of strncat function. |
| Uninitialized locals | -Wuninitialized | Common | Warn if an uninitialized local variable is detected. |
| Unreachable code | -Wunreachable-code | Common | Warn if unreachable code is detected. |
| Unused variable | -Wunused-variable | Common | Warn if an unreferenced identifier is detected. |
| Array bounds pointer arithmetic | -Warray-bounds-pointer-arithmetic | Extended | Warn about pointer operation reaching out of array bounds. |
| Bad function cast | -Wbad-function-cast | Extended | Warn about casting a function call to a non-matching type. |
| C99 extensions | -Wc99-extensions | Extended | Warn about C99 extensions. |
| Cast align | -Wcast-align | Extended | Warn if a pointer cast increases alignment. |
| Char subscripts | -Wchar-subscripts | Extended | Warn if an array subscript has type char. |
| Dangling else | -Wdangling-else | Extended | Warn about possible unintended matching of an else. |
| Declaration after statement | -Wdeclaration-after-statement | Extended | Warn if a declaration is found after a statement in a block, which is not supported in ISO 90. This warning is not displayed when C99 extensions are enabled. |
| Duplicate enum | -Wduplicate-enum | Extended | Warn if an enum has duplicate values. |
| Empty body | -Wempty-body | Extended | Warn if a for, if, or while statement contains an empty body. |
| Float comparisons | -Wfloat-equal | Extended | Warn if floating-point numbers are compared using == or !=. |
| Integer overflow | -Winteger-overflow | Extended | Warn if an overflow occurs in an arithmetic expression. |
| Integer to pointer cast | -Wint-to-pointer-cast | Extended | Warn about casting from a smaller integer type to a pointer type. |
| Invalid noreturn | -Winvalid-noreturn | Extended | Warn if a function specifies the noreturn attribute but does return. |
| Invalid token pasting | -Winvalid-token-paste | Extended | Warn if an invalid preprocessing token was encountered while applying the token pasting operator. |
| Missing braces | -Wmissing-braces | Extended | Warn if an aggregate or union initializer is bracketed incompletely. |
| Missing noreturn | -Wmissing-noreturn | Extended | Warn if a function that might be a candidate for the noreturn attribute is detected. |
| Overlength strings | -Woverlength-strings | Extended | Warn if a string constant is longer than what the C standard requires compilers to handle. |
| Precision loss | -Wconversion | Extended | Warn if implicit conversions might result in the loss of precision. |
| Shadow | -Wshadow | Extended | Warn if a local variable shadows another existing local variable, parameter, or global variable. |
| Sign compare | -Wsign-compare | Extended | Warn if a comparison between signed and unsigned values might produce an incorrect result when the signed value is converted to unsigned. |
| Strict function prototypes | -Wstrict-prototypes | Extended | Warn for old-style function declarations or definitions. |
| Switch | -Wswitch | Extended | Warn if an enumerated value does not have a case in the switch statement. If a default case exists, this warning is not displayed. |
| Switch enum | -Wswitch-enum | Extended | Warn if an enumerated value does not have a case in the switch statement. If a default case exists, this warning is still displayed. |
| Tautological compare | -Wtautological-compare | Extended | Warn if fixed-result comparisons are detected. |
| Typecheck convert | -Wtypecheck-convert | Extended | Detect type mismatch. |
| Unused function | -Wunused-function | Extended | Warn if a static function is declared but is not defined. Also warns if a non-inline static function is unused. |
| Unused label | -Wunused-label | Extended | Warn if a label is unused. |
| Unused value | -Wunused-value | Extended | Warn if an expression value is unused. |
| Used but marked unused | -Wused-but-marked-unused | Extended | Warn if a parameter marked as unused is in fact used in the function. |
| Variable named argument | -Wva-named-param | Extended | Warn if the second parameter of 'va_start' is not the last named argument. |
| Backslash newline escape | -Wbackslash-newline-escape | All | Warn if backslash and newline are separated by space. |
| Built-in macro redefined | -Wbuiltin-macro-redefined | All | Warn if built-in macros, such as __TIME__, are redefined on the command line or by directives. |
| Built-in macro undefined | -Wbuiltin-macro-undefined | All | Warn if built-in macros, such as __TIME__, are undefined on the command line or by directives. |
| Built-in requires header | -Wbuiltin-requires-header | All | Warn about a built-in function requiring a header. |
| Clang-specific extensions | -Wclang | All | Warn if extensions specific to the Clang compiler are detected. Examples: casting to union types, forward references to enum types, zero-length arrays, and other similar situations. |
| Comment | -Wcomment | All | Warn if a comment start sequence /* appears within a /* */ comment, or if a backslash-newline appears within a // comment. |
| Constant conversion | -Wconstant-conversion | All | Warn about implicit value-altering conversions of constants. |
| Constant logical operand | -Wconstant-logical-operand | All | Warn if a logical operator is used instead of a bitwise operator. |
| Constant too large | -Wconstant-too-large | All | Warn if an integer constant is too large for its type. |
| Visibility | -Wvisibility | All | Warn about visibility of redefinitions/declarations in function parameter list. |
| Deprecated declaration | -Wdeprecated-declarations | All | Warn if an __attribute__((deprecated)) declaration is used. |
| Discard qualifiers | -Wdiscard-qual | All | Warn if a qualification is discarded in a situation such as initialization, assignment, or passing an argument. |
| End of directive | -Wend-of-directive | All | Warn if the end of the directive is missing in a pragma declaration. |
| Enum value too large | -Wmicrosoft-enum-value | All | Warn if an enum value is not representable in the underlying type. |
| Excess elements | -Wexcess-elements | All | Warn if excess elements are in a construct. |
| Expected semicolon | -Wexpected-semi | All | Warn if a semicolon (;) is missing at the end of a declaration list. |
| Extern variables initialized | -Wextern-initializer | All | Warn if an extern variable is initialized. |
| Extra tokens | -Wextra-tokens | All | Warn if there is an extra token in a directive. |
| Format | -Wformat | All | Warn if the arguments supplied to printf, scanf, and similar functions are not the appropriate type for the format string specified. Also warns if any conversion specified in the format string is not valid. |
| Four char constants | -Wfour-char-constants | All | Warn if a four-character constant is detected. |
| GNU binary literal | -Wgnu-binary-literal | All | Warn about binary literals being a GNU extension. |
| GNU complex integer | -Wgnu-complex-integer | All | Warn about a complex integer being a GNU extension. |
| GNU compound literal initializer | -Wgnu-compound-literal-initializer | All | Warn that initialization of objects with static storage duration by compound literals is a GNU extension. |
| GNU designator | -Wgnu-designator | All | Warn if a GNU old-style field designator extension is used. |
| GNU folding constant | -Wgnu-folding-constant | All | Warn about variable length arrays being folded to constant arrays as a GNU extension. This warning is not displayed when C99 extensions are enabled. |
| GNU imaginary constant | -Wgnu-imaginary-constant | All | Warn about an imaginary constant being a GNU extension. |
| Ignored Attributes | -Wignored-attributes | All | Warn about invalid or inconsistent attribute usage. |
| Ignored pragmas | -Wignored-pragmas | All | Warn if a pragma option is ignored. |
| Illegal storage | -Willegal-storage | All | Warn about illegal storage class on functions. |
| Implicit function declarations | -Wimplicit-function-declaration | All | Warn if a function is used before it is declared. This warning is not displayed when C99 extensions are enabled. |
| Implicit int | -Wimplicit-int | All | Warn if a declaration does not include a type. |
| Include next | -Winclude-next | All | Warn if a #include_next directive is in the primary source file. |
| Incomplete fields | -Wincomplete-field | All | Incomplete fields may be used only at the end of a struct. |
| Initialization braces | -Wbraces-init | All | Warn if initializer braces are used improperly. |
| Initializer overrides | -Winitializer-overrides | All | Warn if subobject initialization overrides the initialization of other fields or if initializer overrides prior initialization of this subobject. |
| Invalid preprocessing token | -Winvalid-pp-token | All | Warn about an invalid preprocessing token. |
| Line number | -Wline-number | All | Warn if the #line directive is provided with a non-decimal number. |
| Literal range | -Wliteral-range | All | Warn if a constant is too large for the type. |
| Long long | -Wlong-long | All | Warn if the long long type is used. This warning is not displayed when C99 extensions are enabled. |
| Macro name | -Wmacro-name | All | Warn if whitespaces are missing after the macro name. |
| Macro poisoning | -Wmacro-poisoning | All | Warn if the #pragma GCC poison directive is used on an existing macro. |
| Macro redefined | -Wmacro-redefined | All | Warn if a macro is redefined. This warning is not displayed when C99 extensions are enabled. |
| Member redeclare | -Wmember-redeclare | All | Warn if a member of a struct or union is redeclared. |
| Missing declarations | -Wmissing-declarations | All | Warn if a declaration is missing or it is invalid. |
| Missing field initializers | -Wmissing-field-initializers | All | Warn if the initializer of a structure is missing fields. |
| Missing variable declarations | -Wmissing-variable-declarations | All | Warn if a global variable declaration is not preceded by an extern declaration. |
| Multichar | -Wmultichar | All | Warn if a multicharacter constant is used. |
| Negative to unsigned conversions | -Wnegative-to-unsigned | All | Warn if a negative value is converted to unsigned. |
| Non-null | -Wnonnull | All | Warn if a NULL pointer is passed for an argument marked by the nonnull function attribute. |
| Ordered comparison | -Wordered-comparison | All | Warn about improper comparisons of memory addresses. |
| Out-of-scope declarations | -Wout-of-scope-declarations | All | Warn about out-of-scope declarations. |
| Packed | -Wpacked | All | Warn if the packed attribute has no effect on struct layout. |
| Padded | -Wpadded | All | Warn if padding is required to align structure members. |
| Pointer compare | -Wpointer-compare | All | Warn about comparisons involving pointers of different types. |
| Pound warnings | -W#warnings | All | Display warnings specified by the #warning directive. |
| Pragma not supported | -Wpragma-not-supported | All | Warn if an unsupported pragma is encountered. |
| Pragma on-off switch | -Wpragma-on-off-switch | All | Warn if the pragma does not specify ON, OFF, or DEFAULT. |
| Pragma reset | -Wpragma-reset | All | Warn if the pragma reset option is ignored. This warning is not displayed when C99 extensions are enabled. |
| Pragma unused | -Wpragma-unused | All | Warn if inconsistencies in #pragma unused arguments are detected. |
| Return stack address | -Wreturn-stack-address | All | Warn if return of address/reference of stack memory is detected. |
| Shift | -Wshift | All | Warn about unsafe shift operations. |
| Sign conversion | -Wsign-conversion | All | Warn if an unsigned value is implicitly converted to a signed value. |
| Single-parameter main | -Wmain | All | Warn if the main function has only one parameter. |
| Static/non-static declarations | -Wstatic-non-static | All | Warn if a static declaration follows a non-static declaration. |
| Tentative strings | -Wtentative | All | Warn if improper uses of tentative strings are detected. |
| Too many arguments | -Wtoo-many-args | All | Warn if a function call with too many arguments is detected. |
| Trigraphs | -Wtrigraphs | All | Warn if any trigraphs that might change the meaning of the application are encountered. Warnings are not displayed for trigraphs within comments. |
| Undefined identifier | -Wundef | All | Warn if an identifier, that is not a macro, is encountered in a #if directive. Undefined identifiers evaluate to zero. |
| Unexpected token | -Wunexpected-token | All | Warn about unexpected tokens. |
| Unicode | -Wunicode | All | Warn about universal character names. |
| Unknown attributes | -Wunknown-attributes | All | Warn about unknown attributes. |
| Unknown escape sequence | -Wunknown-escape | All | Warn about unknown escape sequences. |
| Unknown pragmas | -Wunknown-pragmas | All | Warn if a #pragma directive is encountered that is not understood. |
| Unused macros | -Wunused-macros | All | Warn if unused macros are detected. |
| Unused parameter | -Wunused-parameter | All | Warn if a function parameter is unused. |
| Variable-length array | -Wvla | All | Warn if a variable-length array is used when C99 extensions are disabled. |
| Variadic call convention | -Wvariadic-call-conv | All | Warn if a variadic function is declared with the __stdcall calling convention in a 32-bit configuration. |
| Variadic macros | -Wvariadic-macros | All | Warn if variadic macros are used when C99 extensions are disabled. |
| Weak attribute | -Wweak | All | Warn about improper usages of constructs containing the weak attribute. |