X-Git-Url: http://git.indexdata.com/?a=blobdiff_plain;f=doc%2Fodr.xml;h=2a5fd7de4775fdd181167cc83d9e104f7b6dcf08;hb=6f5c63a8b759040d31028a4f1437a9cbc7a21fd6;hp=2824d6c481c5b855f8c5d79c548f137e4620bebe;hpb=4cc34f9a4eec65d0eb629d070150dd55c5977522;p=yaz-moved-to-github.git diff --git a/doc/odr.xml b/doc/odr.xml index 2824d6c..2a5fd7d 100644 --- a/doc/odr.xml +++ b/doc/odr.xml @@ -1,4 +1,4 @@ - + The ODR Module Introduction @@ -355,6 +355,57 @@ void do_nothing_useful(int value) + Printing + + When an ODR stream is created of type ODR_PRINT + the ODR module will print the contents of a PDU in a readable format. + By default output is written to the stderr stream. + This behavior can be changed, however, by calling the function + + odr_setprint(ODR o, FILE *file); + + before encoders or decoders are being invoked. + It is also possible to direct the output to a buffer (of indeed + another file), by using the more generic mechanism: + + void odr_set_stream(ODR o, void *handle, + void (*stream_write)(ODR o, void *handle, int type, + const char *buf, int len), + void (*stream_close)(void *handle)); + + Here the user provides an opaque handle and two handlers, + stream_write for writing, + and stream_close which is supposed + to close/free resources associated with handle. + The stream_close handler is optional and + if NULL for the function is provided, it will not be invoked. + The stream_write takes the ODR handle + as parameter, the user defined handle, a type + ODR_OCTETSTRING, ODR_VISIBLESTRING + which indicates the type of contents is being written. + + + Another utility useful for diagnostics (error handling) or as + part of the printing facilities is: + + const char **odr_get_element_path(ODR o); + + which returns a list of current elements that ODR deals with at the + moment. For the returned array, say ar, + ar[0] is the top level element, + ar[n] is the last. The last element has the + property that ar[n+1] == NULL. + + + Element Path for record + + For a database record part of a PresentResponse the + array returned by odr_get_element + is presentResponse, databaseOrSurDiagnostics, ?, record, ?, databaseRecord . The question mark appears due to + unnamed constructions. + + + Diagnostics