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#ifndef Py_PYMACRO_H
#define Py_PYMACRO_H
/* Assert a build-time dependency, as an expression.
Your compile will fail if the condition isn't true, or can't be evaluated
by the compiler. This can be used in an expression: its value is 0.
Example:
#define foo_to_char(foo) \
((char *)(foo) \
+ Py_BUILD_ASSERT_EXPR(offsetof(struct foo, string) == 0))
Written by Rusty Russell, public domain, http://ccodearchive.net/ */
#define Py_BUILD_ASSERT_EXPR(cond) \
(sizeof(char [1 - 2*!(cond)]) - 1)
/* Get the number of elements in a visible array
This does not work on pointers, or arrays declared as [], or function
parameters. With correct compiler support, such usage will cause a build
error (see Py_BUILD_ASSERT_EXPR).
Written by Rusty Russell, public domain, http://ccodearchive.net/
Requires at GCC 3.1+ */
#if (defined(__GNUC__) && !defined(__STRICT_ANSI__) && \
(((__GNUC__ == 3) && (__GNU_MINOR__ >= 1)) || (__GNUC__ >= 4)))
/* Two gcc extensions.
&a[0] degrades to a pointer: a different type from an array */
#define Py_ARRAY_LENGTH(array) \
(sizeof(array) / sizeof((array)[0]) \
+ Py_BUILD_ASSERT_EXPR(!__builtin_types_compatible_p(typeof(array), \
typeof(&(array)[0]))))
#else
#define Py_ARRAY_LENGTH(array) \
(sizeof(array) / sizeof((array)[0]))
#endif
#endif /* Py_PYMACRO_H */
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