Question

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 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_LONGLONG

  sizeof(longlong) where longlong is defined appropriately on the platform.

• 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.)

Platform information

• NPY_CPU_X86

• NPY_CPU_AMD64

• NPY_CPU_IA64

• NPY_CPU_PPC

• NPY_CPU_PPC64

• NPY_CPU_SPARC

• NPY_CPU_SPARC64

• NPY_CPU_S390

• NPY_CPU_PARISC

  New in version 1.3.0.

  CPU architecture of the platform; only one of the above is defined.

  Defined in numpy/npy_cpu.h

• NPY_LITTLE_ENDIAN

• NPY_BIG_ENDIAN

• NPY_BYTE_ORDER

  New in version 1.3.0.

  Portable alternatives to the endian.h macros of GNU Libc. If big endian, NPY_BYTE_ORDER == NPY_BIG_ENDIAN, and similarly for little endian architectures.

  Defined in numpy/npy_endian.h.

• PyArray_GetEndianness()

  New in version 1.3.0.

  Returns the endianness of the current platform. One of NPY_CPU_BIG, NPY_CPU_LITTLE, or NPY_CPU_UNKNOWN_ENDIAN.

Compiler directives

• NPY_LIKELY
• NPY_UNLIKELY
• NPY_UNUSED

Interrupt Handling

• NPY_INTERRUPT_H
• NPY_SIGSETJMP
• NPY_SIGLONGJMP
• NPY_SIGJMP_BUF
• NPY_SIGINT_ON
• NPY_SIGINT_OFF