如何在Cython中使用const

Question

我在这个链接中读到:https://github.com/cython/cython/wiki/FAQ#id35我的Cython 0.20.1应该能够支持const.

但是我的以下代码无法编译:

cdef const double a = 2.5
print(a)

在编译期间,它说

test.pyx:5:5: Assignment to const 'a'
Traceback (most recent call last):
  File "setup1.py", line 11, in <module>
    ext_modules = cythonize(extensions)
  File "X:\WinPython3\python-3.3.5.amd64\lib\site-packages\Cython\Build\Dependencies.py", line 785, in cythonize
    cythonize_one(*args[1:])
  File "X:\WinPython3\python-3.3.5.amd64\lib\site-packages\Cython\Build\Dependencies.py", line 902, in cythonize_one
    raise CompileError(None, pyx_file)
Cython.Compiler.Errors.CompileError: test.pyx

Answer 1

const 适用于函数参数,但不适用于此构造,因为Cython如何将其编译为C.

cdef double a = 2.5

变

double __pyx_v_a;
/* lots of other declarations */

__pyx_v_a = 2.5;

这不适用于const变量.实际上,你不能const在所有的地方使用Cython,你可以在C中使用它.