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gcc error attributes are not allowed on a function-definition Villa Rica, Georgia

If no argument index list is given to the nonnull attribute, all pointer arguments are marked as non-null. GCC knows this automatically. If a symbol previously declared dllimport is later defined, the attribute is ignored in subsequent references, and a warning is emitted. The compiler will generate more efficient code for certain operations on data in the eight bit data area.

mips16 nomips16 On MIPS targets, you can use the mips16 and nomips16 function attributes to locally select or turn off MIPS16 code generation. longcall/shortcallOn the RS/6000 and PowerPC, the longcall attribute causes the compiler to always call this function via a pointer, just as it would if the -mlongcall option had been specified. Since ISO C99 specifies a different semantics for inline , this function attribute is provided as a transition measure and as a useful feature in its own right. void __attribute__ ((visibility ("protected"))) f () { /* Do something. */; } int i __attribute__ ((visibility ("hidden"))); See the ELF gABI for complete details, but the short story is: defaultDefault visibility

This is useful for compile-time checking, especially together with __builtin_constant_p and inline functions where checking the inline function arguments is not possible through extern char [(condition) ? 1 : -1]; tricks. l2 On the Blackfin, this attribute specifies a function to be placed into L2 SRAM. For example, void fatal () __attribute__ ((noreturn)); void fatal (...) { ... /* Print error message. */ ... You can declare them noreturn to tell the compiler this fact.

Note, for the ARM, you can specify the kind of interrupt to be handled by adding an optional parameter to the interrupt attribute like this: void f () __attribute__ ((interrupt ("IRQ"))); To keep such calls from being optimized away, put asm (""); (see Extended Asm ) in the called function, to serve as a special side-effect. The long_call attribute causes the compiler to always call the function by first loading its address into a register and then using the contents of that register. You must use GAS and GLD from GNU binutils version 2.7 or later for this attribute to work correctly.

For ARM, the long_call attribute indicates that the function might be far away from the call site and require a different (more expensive) calling sequence. However, the attribute is ignored for virtual methods to allow creation of vtables using thunks. Some of common examples of pure functions are strlen or memcmp. The warnings for missing or incorrect sentinels are enabled with -Wformat .

current community chat Stack Overflow Meta Stack Overflow your communities Sign up or log in to customize your list. The compiler always (unless `-ffreestanding' is used) checks formats for the standard library functions printf, fprintf, sprintf, scanf, fscanf, sscanf, strftime, vprintf, vfprintf and vsprintf whenever such warnings are requested (using How exactly does the typical shell "fork bomb" calls itself twice? Some file formats do not support arbitrary sections so the section attribute is not available on all platforms.

pure Many functions have no effects except the return value and their return value depends only on the parameters and/or global variables. It is impossible to generate #pragma commands from a macro. In the following example 2 bytes are saved for each call to function foo . Browse other questions tagged c++ gcc powerpc or ask your own question.

What sense of "hack" is involved in "five hacks for using coffee filters"? The compiler will generate function entry and exit sequences suitable for use in an interrupt handler when this attribute is present. When applied to C++ classes, the attribute marks non-inlined member functions and static data members as imports. The warning also includes the location of the declaration of the deprecated function, to enable users to easily find further information about why the function is deprecated, or what they should

Note, on the ARC, you must specify the kind of interrupt to be handled in a parameter to the interrupt attribute like this: void f () __attribute__ ((interrupt ("ilink1"))); Permissible values extern void isUncachedMemory() __attribute__((__const__)) ; inline void isUncachedMemory() {} extern void isUncachedMemory() __attribute__((__const__)) ; Should this work? Register banks are stacked in first-in last-out (FILO) sequence. These attributes override the -mips16 and -mno-mips16 options on the command line (see MIPS Options ).

model (model-name) Use this attribute on the M32R/D to set the addressability of an object, and the code generated for a function. This attribute is available in GCC 4.1.3 and later. It is an error to explicitly specify any other visibility. eightbit_dataUse this attribute on the H8/300, H8/300H, and H8S to indicate that the specified variable should be placed into the eight bit data section.

Other attributes, including section are supported for variables declarations (see section 5.32 Specifying Attributes of Variables) and for types (see section 5.33 Specifying Attributes of Types). See An Inline Function is As Fast As a Macro . A simple example (not the inheritance case) class A { public: A(int _anInt) __attribute__ ((deprecated)) { anInt = _anInt; } private: int anInt; }; int main(void) { A aInstance(42); } Fails Failure to inline such a function is diagnosed as an error.

Not all ELF targets support this attribute. The section attribute specifies that a function lives in a particular section. tiny_dataUse this attribute on the H8/300H and H8S to indicate that the specified variable should be placed into the tiny data section. Using this attribute can improve optimization.

An alternative way to declare that a function does not return, which works in the current version and in some older versions, is as follows: typedef void voidfn (); volatile voidfn See Options Controlling C Dialect . The attribute const is not implemented in GCC versions earlier than 2.5. If the compiler determines that a null pointer is passed in an argument slot marked as non-null, and the -Wnonnull option is enabled, a warning is issued.

These attributes are not currently implemented for Objective-C. The specified function will not have prologue/epilogue sequences generated by the compiler. OS_main OS_task On AVR, functions with the OS_main or OS_task attribute do not save/restore any call-saved register in their prologue/epilogue. Functions that take a variable number of arguments continue to pass all of their floating-point arguments on the stack.

fastcall On x86-32 targets, the fastcall attribute causes the compiler to pass the first argument (if of integral type) in the register ECX and the second argument (if of integral type) Is the NHS wrong about passwords? The short_call attribute always places the offset to the function from the call site into the BL instruction directly. However, it has been found convenient to use __attribute__ to achieve a natural attachment of attributes to their corresponding declarations, whereas #pragma GCC is of use for constructs that do not

Interesting non-pure functions are functions with infinite loops or those depending on volatile memory or other system resource, that may change between two consecutive calls (such as feof in a multithreading One drawback to using this attribute is that a pointer to a variable marked as dllimport cannot be used as a constant address. Should it be? While it is possible to define the function with a message in .gnu.warning* section, when using this attribute the problem is diagnosed earlier and with exact location of the call even