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Compiler-specific Features
4.2.4 __declspec(noreturn)
The __declspec(noreturn) attribute asserts that a function never returns.
Note
This attribute has the function equivalent __attribute((noreturn)). However,
__attribute((noreturn)) and __declspec(noreturn) differ in that when compiling a
function definition, if the function reaches an explicit or implicit return,
__attribute((noreturn)) is ignored and the compiler generates a warning. This does not
apply to __declspec(noreturn).
Usage
Use this attribute to reduce the cost of calling a function that never returns, such as
exit(). If a noreturn function returns to its caller, the behavior is undefined.
Restrictions
The return address is not preserved when calling the noreturn function. This limits the
ability of a debugger to display the call stack.
Example
__declspec(noreturn) void overflow(void); // never return on overflow
int negate(int x)
{
if (x == 0x80000000) overflow();
return -x;
}
See also
• __attribute__((noreturn)) on page 4-36.
4.2.5 __declspec(nothrow)
The __declspec(nothrow) attribute asserts that a call to a function never results in a C++
exception being propagated from the call into the caller.
The ARM library headers automatically add this qualifier to declarations of C functions
that, according to the ISO C Standard, can never throw.
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