System configuration ==================== .. sectionauthor:: Travis E. Oliphant When NumPy is built, information about system configuration is recorded, and is made available for extension modules using Numpy's C API. These are mostly defined in ``numpyconfig.h`` (included in ``ndarrayobject.h``). The public symbols are prefixed by ``NPY_*``. Numpy also offers some functions for querying information about the platform in use. For private use, Numpy also constructs a ``config.h`` in the NumPy include directory, which 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. Data type sizes --------------- The :cdata:`NPY_SIZEOF_{CTYPE}` constants are defined so that sizeof information is available to the pre-processor. .. cvar:: NPY_SIZEOF_SHORT sizeof(short) .. cvar:: NPY_SIZEOF_INT sizeof(int) .. cvar:: NPY_SIZEOF_LONG sizeof(long) .. cvar:: NPY_SIZEOF_LONG_LONG sizeof(longlong) where longlong is defined appropriately on the platform (A macro defines **NPY_SIZEOF_LONGLONG** as well.) .. cvar:: NPY_SIZEOF_PY_LONG_LONG .. cvar:: NPY_SIZEOF_FLOAT sizeof(float) .. cvar:: NPY_SIZEOF_DOUBLE sizeof(double) .. cvar:: NPY_SIZEOF_LONG_DOUBLE sizeof(longdouble) (A macro defines **NPY_SIZEOF_LONGDOUBLE** as well.) .. cvar:: NPY_SIZEOF_PY_INTPTR_T Size of a pointer on this platform (sizeof(void \*)) (A macro defines NPY_SIZEOF_INTP as well.) Platform information -------------------- .. cvar:: NPY_CPU_X86 .. cvar:: NPY_CPU_AMD64 .. cvar:: NPY_CPU_IA64 .. cvar:: NPY_CPU_PPC .. cvar:: NPY_CPU_PPC64 .. cvar:: NPY_CPU_SPARC .. cvar:: NPY_CPU_SPARC64 .. cvar:: NPY_CPU_S390 .. cvar:: NPY_CPU_PARISC .. versionadded:: 1.3.0 CPU architecture of the platform; only one of the above is defined. Defined in ``numpy/npy_cpu.h`` .. cvar:: NPY_LITTLE_ENDIAN .. cvar:: NPY_BIG_ENDIAN .. cvar:: NPY_BYTE_ORDER .. versionadded:: 1.3.0 Portable alternatives to the ``endian.h`` macros of GNU Libc. If big endian, :cdata:`NPY_BYTE_ORDER` == :cdata:`NPY_BIG_ENDIAN`, and similarly for little endian architectures. Defined in ``numpy/npy_endian.h``. .. cfunction:: PyArray_GetEndianness() .. versionadded:: 1.3.0 Returns the endianness of the current platform. One of :cdata:`NPY_CPU_BIG`, :cdata:`NPY_CPU_LITTLE`, or :cdata:`NPY_CPU_UNKNOWN_ENDIAN`.