109 lines
3.5 KiB
Markdown
109 lines
3.5 KiB
Markdown
# Limitations
|
|
|
|
## Nameof
|
|
|
|
* If argument does not have name, occurs the compilation error `"Expression does not have a name."`.
|
|
|
|
## Nameof Type
|
|
|
|
* To check is nameof type supported compiler use macro `NAMEOF_TYPE_SUPPORTED` or constexpr constant `nameof::is_nameof_type_supported`.
|
|
|
|
* This library uses a compiler-specific hack (based on `__PRETTY_FUNCTION__` / `__FUNCSIG__`), which works on Clang >= 5, MSVC >= 15.3 and GCC >= 7.
|
|
|
|
* Nameof type returns compiler-specific type name.
|
|
|
|
* If argument does not have name, occurs the compilation error `"Expression does not have a name."`.
|
|
|
|
## Nameof Enum
|
|
|
|
* To check is nameof enum supported compiler use macro `NAMEOF_ENUM_SUPPORTED` or constexpr constant `nameof::is_nameof_enum_supported`.
|
|
|
|
* This library uses a compiler-specific hack (based on `__PRETTY_FUNCTION__` / `__FUNCSIG__`), which works on Clang >= 5, MSVC >= 15.3 and GCC >= 9.
|
|
|
|
* Enum can't reflect if the enum is a forward declaration.
|
|
|
|
* Enum value must be in range `[NAMEOF_ENUM_RANGE_MIN, NAMEOF_ENUM_RANGE_MAX]`.
|
|
|
|
* By default `NAMEOF_ENUM_RANGE_MIN = -128`, `NAMEOF_ENUM_RANGE_MAX = 128`.
|
|
|
|
* `NAMEOF_ENUM_RANGE_MIN` must be less or equals than `0` and must be greater than `INT16_MIN`.
|
|
|
|
* `NAMEOF_ENUM_RANGE_MAX` must be greater than `0` and must be less than `INT16_MAX`.
|
|
|
|
* If need another range for all enum types by default, redefine the macro `NAMEOF_ENUM_RANGE_MIN` and `NAMEOF_ENUM_RANGE_MAX`.
|
|
|
|
```cpp
|
|
#define NAMEOF_ENUM_RANGE_MIN 0
|
|
#define NAMEOF_ENUM_RANGE_MAX 256
|
|
#include <nameof.hpp>
|
|
```
|
|
|
|
* If need another range for specific enum type, add specialization `enum_range` for necessary enum type. Specialization of `enum_range` must be injected in `namespace nameof`.
|
|
|
|
```cpp
|
|
#include <nameof.hpp>
|
|
|
|
enum class number { one = 100, two = 200, three = 300 };
|
|
|
|
namespace nameof {
|
|
template <>
|
|
struct enum_range<number> {
|
|
static constexpr int min = 100;
|
|
static constexpr int max = 300;
|
|
};
|
|
} // namespace nameof
|
|
```
|
|
|
|
* If you hit a message like this:
|
|
|
|
```text
|
|
[...]
|
|
note: constexpr evaluation hit maximum step limit; possible infinite loop?
|
|
```
|
|
|
|
Change the limit for the number of constexpr evaluated:
|
|
* MSVC `/constexpr:depthN`, `/constexpr:stepsN` <https://docs.microsoft.com/en-us/cpp/build/reference/constexpr-control-constexpr-evaluation>
|
|
* Clang `-fconstexpr-depth=N`, `-fconstexpr-steps=N` <https://clang.llvm.org/docs/UsersManual.html#controlling-implementation-limits>
|
|
* GCC `-fconstexpr-depth=N`, `-fconstexpr-loop-limit=N`, `-fconstexpr-ops-limit=N` <https://gcc.gnu.org/onlinedocs/gcc-9.2.0/gcc/C_002b_002b-Dialect-Options.html>
|
|
|
|
* Nameof enum obtains the first defined value enums, and won't work if value are aliased.
|
|
|
|
```cpp
|
|
enum ShapeKind {
|
|
ConvexBegin = 0,
|
|
Box = 0, // Won't work.
|
|
Sphere = 1,
|
|
ConvexEnd = 2,
|
|
Donut = 2, // Won't work too.
|
|
Banana = 3,
|
|
COUNT = 4,
|
|
};
|
|
// nameof::nameof_enum(ShapeKind::Box) -> "ConvexBegin"
|
|
// NAMEOF_ENUM(ShapeKind::Box) -> "ConvexBegin"
|
|
```
|
|
|
|
Work around the issue:
|
|
|
|
```cpp
|
|
enum ShapeKind {
|
|
// Convex shapes, see ConvexBegin and ConvexEnd below.
|
|
Box = 0,
|
|
Sphere = 1,
|
|
|
|
// Non-convex shapes.
|
|
Donut = 2,
|
|
Banana = 3,
|
|
|
|
COUNT = Banana + 1,
|
|
|
|
// Non-reflected aliases.
|
|
ConvexBegin = Box,
|
|
ConvexEnd = Sphere + 1,
|
|
};
|
|
// nameof::nameof_enum(ShapeKind::Box) -> "Box"
|
|
// NAMEOF_ENUM(ShapeKind::Box) -> "Box"
|
|
|
|
// Non-reflected aliases.
|
|
// nameof::nameof_enum(ShapeKind::ConvexBegin) -> "Box"
|
|
// NAMEOF_ENUM(ShapeKind::ConvexBegin) -> "Box"
|
|
```
|