System configuration

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