1 files changed, 110 insertions, 0 deletions
diff --git a/doc/source/reference/c-api.config.rst b/doc/source/reference/c-api.config.rst
new file mode 100644
index 000000000..30dd1c6fb
--- /dev/null
+++ b/doc/source/reference/c-api.config.rst
@@ -0,0 +1,110 @@
+Configuration defines
+=====================
+
+.. sectionauthor:: Travis E. Oliphant
+
+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. It is
+included by the arrayobject.h file.
+
+
+Guaranteed to be defined
+------------------------
+
+The :cdata:`SIZEOF_{CTYPE}` constants are defined so that sizeof
+information is available to the pre-processor.
+
+.. cvar:: CHAR_BIT
+
+    The number of bits of a char. The char is the unit of all sizeof
+    definitions
+
+.. cvar:: SIZEOF_SHORT
+
+    sizeof(short)
+
+.. cvar:: SIZEOF_INT
+
+    sizeof(int)
+
+.. cvar:: SIZEOF_LONG
+
+    sizeof(long)
+
+.. cvar:: SIZEOF_LONG_LONG
+
+    sizeof(longlong) where longlong is defined appropriately on the
+    platform (A macro defines **SIZEOF_LONGLONG** as well.)
+
+.. cvar:: SIZEOF_PY_LONG_LONG
+    
+
+.. cvar:: SIZEOF_FLOAT
+
+    sizeof(float)
+
+.. cvar:: SIZEOF_DOUBLE
+
+    sizeof(double)
+
+.. cvar:: SIZEOF_LONG_DOUBLE
+
+    sizeof(longdouble) (A macro defines **SIZEOF_LONGDOUBLE** as well.)
+
+.. cvar:: SIZEOF_PY_INTPTR_T
+
+    Size of a pointer on this platform (sizeof(void \*)) (A macro defines
+    SIZEOF_INTP as well.)
+
+
+Possible defines
+----------------
+
+These defines will cause the compilation to ignore compatibility code
+that is placed in NumPy and use the system code instead. If they are
+not defined, then the system does not have that capability. 
+
+.. cvar:: HAVE_LONGDOUBLE_FUNCS
+
+    System has C99 long double math functions.
+
+.. cvar:: HAVE_FLOAT_FUNCS
+
+    System has C99 float math functions.
+
+.. cvar:: HAVE_INVERSE_HYPERBOLIC
+
+    System has inverse hyperbolic functions: asinh, acosh, and atanh.
+
+.. cvar:: HAVE_INVERSE_HYPERBOLIC_FLOAT
+
+    System has C99 float extensions to inverse hyperbolic functions:
+    asinhf, acoshf, atanhf
+
+.. cvar:: HAVE_INVERSE_HYPERBOLIC_LONGDOUBLE
+
+    System has C99 long double extensions to inverse hyperbolic functions:
+    asinhl, acoshl, atanhl.
+
+.. cvar:: HAVE_ISNAN
+
+    System has an isnan function.
+
+.. cvar:: HAVE_ISINF
+
+    System has an isinf function.
+
+.. cvar:: HAVE_LOG1P
+
+    System has the log1p function: :math:`\log\left(x+1\right)`.
+
+.. cvar:: HAVE_EXPM1
+
+    System has the expm1 function: :math:`\exp\left(x\right)-1`.
+
+.. cvar:: HAVE_RINT
+
+    System has the rint function.
+