Unable to write two tables in a RData file

[RudolphDev]

Hello,

I would use your library to write RData in a C++ software but i can't use it.
I try to write an RData from your example, everything works but when i want to add a second table the produced RData can't be loaded in R. I tried to load with R 3.5 and R 4.0 in the both cases R gave me the error : ReadItem : unknown type 0, perhaps written by later version of R ?

This is the script I use:

int fd = open("/data/test.RData", O_CREAT | O_WRONLY, 0644);
rdata_writer_t *mp_rdataWriter = rdata_writer_init(&write_data, RDATA_WORKSPACE);
int m_rowCount = 3;

rdata_column_t *col1 =
  rdata_add_column(mp_rdataWriter, "column1", RDATA_TYPE_REAL);
rdata_column_t *col2 =
  rdata_add_column(mp_rdataWriter, "column2", RDATA_TYPE_STRING);
rdata_column_t *col3 =
  rdata_add_column(mp_rdataWriter, "column3", RDATA_TYPE_REAL);
rdata_column_t *col4 =
  rdata_add_column(mp_rdataWriter, "column4", RDATA_TYPE_STRING);

rdata_begin_file(mp_rdataWriter, &fd);
rdata_begin_table(mp_rdataWriter, "my_table");


rdata_begin_column(mp_rdataWriter, col1, m_rowCount);
rdata_append_real_value(mp_rdataWriter, 0.0);
rdata_append_real_value(mp_rdataWriter, 100.0);
rdata_append_real_value(mp_rdataWriter, 200.0);
rdata_end_column(mp_rdataWriter, col1);


rdata_begin_column(mp_rdataWriter, col2, m_rowCount);
rdata_append_string_value(mp_rdataWriter, "hello");
rdata_append_string_value(mp_rdataWriter, "goodbye");
rdata_append_string_value(mp_rdataWriter, "test");
rdata_end_column(mp_rdataWriter, col2);

rdata_end_table(mp_rdataWriter, m_rowCount, "My data set");

rdata_begin_table(mp_rdataWriter, "test2");

rdata_begin_column(mp_rdataWriter, col3, 2);
rdata_append_real_value(mp_rdataWriter, 0.0);
rdata_append_real_value(mp_rdataWriter, 100.0);
rdata_end_column(mp_rdataWriter, col3);

rdata_begin_column(mp_rdataWriter, col4, 2);
rdata_append_string_value(mp_rdataWriter, "bla");
rdata_append_string_value(mp_rdataWriter, "blo");
rdata_end_column(mp_rdataWriter, col4);

rdata_end_table(mp_rdataWriter, 2, "Test table 2");

rdata_end_file(mp_rdataWriter);
close(fd);

and

ssize_t
McqrRdata::write_data(const void *bytes, size_t len, void *ctx)
{
  int fd = *(int *)ctx;
  return write(fd, bytes, len);
}

Thank you

Thomas

[evanmiller]

Thanks for the report. This looks like a bug. I'll leave it open until I get a chance to look into it.

[evanmiller]

One issue is that each table will iterate over all of the writer's columns when writing the "names" and "var.labels" attributes. The columns need to be associated with the individual tables rather than the writer object somehow.

[cgilles]

Hi,

I'm faced exactly the same problem in my project exporting multiple tables in the same RData file. The file is created but it's impossible to load the file in R.

Creating one table work fine, more than one no.

Best

Gilles Caulier