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Diffstat (limited to 'docs/reference/speed_python.rst')
| -rw-r--r-- | docs/reference/speed_python.rst | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/docs/reference/speed_python.rst b/docs/reference/speed_python.rst index c5aa80c6e..f2d7739fb 100644 --- a/docs/reference/speed_python.rst +++ b/docs/reference/speed_python.rst @@ -293,10 +293,12 @@ microseconds. The rules for casting are as follows: * The argument to a bool cast must be integral type (boolean or integer); when used as a return type the viper function will return True or False objects. * If the argument is a Python object and the cast is ``ptr``, ``ptr``, ``ptr16`` or ``ptr32``, - then the Python object must either have the buffer protocol with read-write capabilities - (in which case a pointer to the start of the buffer is returned) or it must be of integral - type (in which case the value of that integral object is returned). - + then the Python object must either have the buffer protocol (in which case a pointer to the + start of the buffer is returned) or it must be of integral type (in which case the value of + that integral object is returned). + +Writing to a pointer which points to a read-only object will lead to undefined behaviour. + The following example illustrates the use of a ``ptr16`` cast to toggle pin X1 ``n`` times: .. code:: python |