diff options
Diffstat (limited to 'doc/source/reference/c-api.array.rst')
| -rw-r--r-- | doc/source/reference/c-api.array.rst | 31 |
1 files changed, 24 insertions, 7 deletions
diff --git a/doc/source/reference/c-api.array.rst b/doc/source/reference/c-api.array.rst index 1291dc93c..90bb56b2d 100644 --- a/doc/source/reference/c-api.array.rst +++ b/doc/source/reference/c-api.array.rst @@ -257,7 +257,7 @@ From scratch PyTypeObject* subtype, int nd, npy_intp* dims, int type_num, \ npy_intp* strides, void* data, int itemsize, int flags, PyObject* obj) - This is similar to :c:func:`PyArray_DescrNew` (...) except you + This is similar to :c:func:`PyArray_NewFromDescr` (...) except you specify the data-type descriptor with *type_num* and *itemsize*, where *type_num* corresponds to a builtin (or user-defined) type. If the type always has the same number of bytes, then @@ -455,8 +455,7 @@ From other objects is deleted (presumably after your calculations are complete), its contents will be copied back into *op* and the *op* array will be made writeable again. If *op* is not writeable to begin - with, then an error is raised. If *op* is not already an array, - then this flag has no effect. + with, or if it is not already an array, then an error is raised. .. c:var:: NPY_ARRAY_BEHAVED @@ -2887,10 +2886,10 @@ to. to a C-array of :c:type:`npy_intp`. The Python object could also be a single number. The *seq* variable is a pointer to a structure with members ptr and len. On successful return, *seq* ->ptr contains a - pointer to memory that must be freed to avoid a memory leak. The - restriction on memory size allows this converter to be - conveniently used for sequences intended to be interpreted as - array shapes. + pointer to memory that must be freed, by calling :c:func:`PyDimMem_FREE`, + to avoid a memory leak. The restriction on memory size allows this + converter to be conveniently used for sequences intended to be + interpreted as array shapes. .. c:function:: int PyArray_BufferConverter(PyObject* obj, PyArray_Chunk* buf) @@ -3063,6 +3062,24 @@ the C-API is needed then some additional steps must be taken. header file as long as you make sure that NO_IMPORT_ARRAY is #defined before #including that file. + Internally, these #defines work as follows: + + * If neither is defined, the C-API is declared to be + :c:type:`static void**`, so it is only visible within the + compilation unit that #includes numpy/arrayobject.h. + * If :c:macro:`PY_ARRAY_UNIQUE_SYMBOL` is #defined, but + :c:macro:`NO_IMPORT_ARRAY` is not, the C-API is declared to + be :c:type:`void**`, so that it will also be visible to other + compilation units. + * If :c:macro:`NO_IMPORT_ARRAY` is #defined, regardless of + whether :c:macro:`PY_ARRAY_UNIQUE_SYMBOL` is, the C-API is + declared to be :c:type:`extern void**`, so it is expected to + be defined in another compilation unit. + * Whenever :c:macro:`PY_ARRAY_UNIQUE_SYMBOL` is #defined, it + also changes the name of the variable holding the C-API, which + defaults to :c:data:`PyArray_API`, to whatever the macro is + #defined to. + Checking the API Version ^^^^^^^^^^^^^^^^^^^^^^^^ |