Question

Is there a C (not C++, Boost etc.) library for providing cross platform datatypes ?

To elaborate, I want to store an int in a file in a 32-bit linux machine, read the file and the same int from a 64-bit windows machine. Is this possible ?

Update: I do not want to use sqlite or some kind of database either. I want a library which can help me in using the data types throughout my code.

Answer 1

If all you want to do is store 32 bits signed integers, just decide on a format, for example big endian. You can then write the serialisation/deserialisation yourself:

void write_int32_be (int32_t i, FILE *f)
{
  uint8_t buf[4];

  buf[0] = ((uint32_t)i >> 24);
  buf[1] = ((uint32_t)i >> 16) & 0xFF;
  buf[2] = ((uint32_t)i >> 8) & 0xFF;
  buf[3] = (uint32_t)i & 0xFF;
  fwrite (buf, 4, 1, f);
}

int32_t read_int32_be (FILE *f)
{
  uint8_t buf[4];

  fread (buf, 4, 1, f);

  return ((uint32_t)buf[0] << 24) |
         ((uint32_t)buf[1] << 16) |
         ((uint32_t)buf[2] << 8) |
          (uint32_t)buf[3];
}

If you need a variety of types, use a library like tpl, Eet, Avro, protobuf-c or an implementation of a standard like XDR, JSON, or ASN.1. If you have large numerical data sets use something like HDF or NetCDF.