double_conversion

Records

Functions

```
int StrLength (const char * string)
```
Defined at line 181 of file ../../third_party/double-conversion/double-conversion/utils.h
```
template <class Dest, class Source>
```
```
Dest BitCast (const Source & source)
```
The type-based aliasing rule allows the compiler to assume that pointers of

different types (for some definition of different) never alias each other.

Thus the following code does not work:

float f = foo();

int fbits = *(int*)(

&f

);

The compiler 'knows' that the int pointer can't refer to f since the types

don't match, so the compiler may cache f in a register, leaving random data

in fbits. Using C++ style casts makes no difference, however a pointer to

char data is assumed to alias any other pointer. This is the 'memcpy

exception'.

Bit_cast uses the memcpy exception to move the bits from a variable of one

type of a variable of another type. Of course the end result is likely to

be implementation dependent. Most compilers (gcc-4.2 and MSVC 2005)

will completely optimize BitCast away.

There is an additional use for BitCast.

Recent gccs will warn when they see casts that may result in breakage due to

the type-based aliasing rule. If you have checked that there is no breakage

you can use BitCast to cast one pointer type to another. This confuses gcc

enough that it can no longer see that you have cast one pointer type to

another thus avoiding the warning.

Defined at line 335 of file ../../third_party/double-conversion/double-conversion/utils.h
```
template <class Destclass Source>
```
```
Dest BitCast (Source * source)
```
Defined at line 352 of file ../../third_party/double-conversion/double-conversion/utils.h