-Writes the specified amount of bytes using the data of \it{buffer}.
-\it{WARNING!} The buffer absolutely needs to have at least the specified size.
+Writes up to the specified amount of bytes using the data of {\it buffer}. Note
+that not all data can always be written so you must check the number of bytes
+really written to the stream using \helpref{LastWrite()}{wxoutputstreamlastwrite}
+when this function returns. In some cases (for example a write end of a pipe
+which is currently full) it is even possible that there is no errors and zero
+bytes have been written.