Type Conversions¶
Rice converts fundamental types to their equivalent Ruby types. Fundamental types include nullptr, bool, numeric types (integer, float, double, complex) and char types.
Type conversion is easy to understand because it is familiar to programmers. When you pass a boolean or integer into a method, you don't expect the method is going to change it - instead it just gets a copy.
Since they are copied, instances of fundamental types are disconnected. If a Ruby string is converted to a std::string then the two strings are independent and changes in one will not be reflected in the other.
Built In Conversions¶
Rice supports all fundamental types out of the box. It also includes special handling for char* which is converted to a Ruby String. In addition, various STL classes are also converted as described in the STL documentation.
| C++ Type | Other Name | Ruby Type |
|---|---|---|
| bool | TrueClass / FalseClass | |
| int8_t / uint8_t | char | String (binary encoding) |
| int8_t / uint8_t | char[] | String (binary encoding) |
| int8_t / uint8_t | char* | String (binary encoding) |
| int8_t | signed char | String (binary encoding) |
| int8_t[] | signed char[] | String (binary encoding) |
| int8_t | unsigned char | String (binary encoding) |
| int8_t[] | unsigned char[] | String (binary encoding) |
| int16_t | short | Integer |
| int16_t[] | short[] | String (binary encoding) |
| uint16_t | unsigned short | Integer |
| uint16_t[] | unsigned short[] | String (binary encoding) |
| int32_t | int | Integer |
| int32_t[] | int[] | String (binary encoding) |
| uint32_t | unsigned int | Integer |
| uint32_t[] | unsigned int[] | String (binary encoding) |
| int64_t | long | Integer |
| int64_t[] | long[] | String (binary encoding) |
| uint64_t | unsigned long | Integer |
| int64_t[] | unsigned long[] | String (binary encoding) |
| int64_t | long long | Integer |
| int64_t[] | long long[] | String (binary encoding) |
| uint64_t | unsigned long long | Integer |
| int64_t[] | unsigned long long[] | String (binary encoding) |
| float | Float | |
| float[] | String (binary encoding) | |
| double | Float | |
| double[] | String (binary encoding) |
Memory Management¶
Because data is copied, it is up to each language to manage its own memory. For example, the following code would cause a memory leak:
char* leakMemory()
{
char* data = new char[BUFFER_SIZE];
return data;
}
Class rb_cTest =
define_class("Test")
.define_function("leak_memory", &leakMemory);
The leak happens because Ruby does not take ownership of the char* and thus it is never freed. For more information refer to the memory management section.