Configuration defines

When NumPy is built, a configuration file is constructed and placed as config.h in the NumPy include directory. This configuration file ensures that specific macros are defined and defines other macros based on whether or not your system has certain features. This file is private, and is not exported by numpy (that is a python extension which use the numpy C API will not see those symbols), to avoid namespace pollution.

Some of those defines have a public equivalent, which are defined in numpyconfig.h (included in ndarrayobject.h). The public symbols are prefixed by NPY_*.

Guaranteed to be defined

The NPY_SIZEOF_{CTYPE} constants are defined so that sizeof information is available to the pre-processor.

NPY_SIZEOF_SHORT

sizeof(short)

NPY_SIZEOF_INT

sizeof(int)

NPY_SIZEOF_LONG

sizeof(long)

NPY_SIZEOF_LONG_LONG

sizeof(longlong) where longlong is defined appropriately on the platform (A macro defines NPY_SIZEOF_LONGLONG as well.)

NPY_SIZEOF_PY_LONG_LONG

NPY_SIZEOF_FLOAT

sizeof(float)

NPY_SIZEOF_DOUBLE

sizeof(double)

NPY_SIZEOF_LONG_DOUBLE

sizeof(longdouble) (A macro defines NPY_SIZEOF_LONGDOUBLE as well.)

NPY_SIZEOF_PY_INTPTR_T

Size of a pointer on this platform (sizeof(void *)) (A macro defines NPY_SIZEOF_INTP as well.)