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SP_get_stream_user_data()#include <sicstus/sicstus.h> spio_t_error_code SP_get_stream_user_data( SP_stream *stream, void const *user_class, void **puser_data);
Get the user data of a user defined stream of a particular class.
An arbitrary stream. It is legal, and often useful, to call
SP_get_stream_user_data() on a stream even if it is not known
whether the stream is in fact a user defined stream of a particular
class.
On success, *puser_data will be set to the user_data
value used when the stream was created.
On success, *puser_data is assigned and
SPIO_S_NOERR or some other success code is returned.
On failure, e.g. if the stream was not created with this
user_class, an error code is returned.
This function is used in order to recognize streams of a particular
type (or class). At the same time as it verifies the type of
stream it also returns the user_data which gives the caller a
handle to the internal state of the user defined stream.
The following sample illustrates how all streams of a particular class
can be found and closed. This function mimics the behavior of the
SP_FCLOSE_OPTION_USER_STREAMS option to SP_fclose, see
cpg-ref-SP_fclose.
spio_t_error_code close_streams(void const *user_class, int force)
{
spio_t_error_code ecode = SPIO_E_ERROR;
SP_stream *stream;
SP_stream *next_stream;
void *user_data;
spio_t_bits fclose_options = 0;
if (force) fclose_options |= SP_FCLOSE_OPTION_FORCE;
stream = NULL; /* means start of list of stream */
do
{
/* Note: We need to do this before closing stream */
ecode = SP_next_stream(stream, &next_stream);
if (SPIO_FAILED(ecode)) goto barf;
if (stream != NULL)
{
if (SPIO_SUCCEEDED(SP_get_stream_user_data(stream, user_class, &user_data)))
{
/* This is the right class of stream, close it */
ecode = SP_fclose(stream, fclose_options);
if (SPIO_FAILED(ecode))
{
if (!force) goto barf; /* ignore error if force */
}
}
}
stream = next_stream;
}
while (stream != NULL);
return SPIO_S_NOERR;
barf:
return ecode;
}
cpg-ref-SP_create_stream. Defining a New Stream.