h6. [[OS SWI Calls]] h6(. » OS_Args h2. OS_Args h5. (SWI &09) |_<^{width:3em}. Entry | | |<^. R0|<^. Reason Code | |<^. R1|<^. File handle | |<^. R2|<^. Attribute (per reason code) | |_<^{width:3em}. Exit || |\2<^. Different per reason code| h4. Reason Codes |_<^{width:3em}. #|_<^. Description| |<^. 0|[[OS_Args 0|Read pointer/FS]]| |<^. 1|[[OS_Args 1|Write pointer]]| |<^. 2|[[OS_Args 2|Read extent]]| |<^. 3|[[OS_Args 3|Write extent]]| |<^. 4|[[OS_Args 4|Read allocated size]]| |<^. 5|[[OS_Args 5|Read EOF status]]| |<^. 6|[[OS_Args 6|Reserve space]]| |<^. 7|[[OS_Args 7|Read pathname of open file]]| |<^. 8|[[OS_Args 8|Inform of changed open file]]| |<^. 9|[[OS_Args 9|IOCtl]]| |<^. 254|[[OS_Args 254|Read info on file handle]]| |<^. 255|[[OS_Args 255|Flush file(s)]]| h4. Use The purpose of this call is to read or write to an open file. h4. Notes Each reason code specifies a different use for this call.