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| -rw-r--r-- | docs/concepts.rst | 1 |
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diff --git a/docs/concepts.rst b/docs/concepts.rst index 122d29c..d326114 100644 --- a/docs/concepts.rst +++ b/docs/concepts.rst @@ -50,6 +50,7 @@ There are a few generic rules for callback functions: #) Use state to store your own data, such as a file descriptor. #) *bytes_written* and *bytes_left* are updated by pb_write and pb_read. #) Your callback may be used with substreams. In this case *bytes_left*, *bytes_written* and *max_size* have smaller values than the original stream. Don't use these values to calculate pointers. +#) Always read or write the full requested length of data. For example, POSIX *recv()* needs the *MSG_WAITALL* parameter to accomplish this. Output streams -------------- |