data is alvays 1970

[texrg]

Is possible to add function to set/read data creating file inside tar?

[rxi]

If you want more control when writing a header use the mtar_write_header() function. The implementation of mtar_write_file_header() can be used as a starting point. The mtime field can be used to set the modified time:

int mtar_write_file_header(mtar_t *tar, const char *name, unsigned size) {
  mtar_header_t h;
  /* Build header */
  memset(&h, 0, sizeof(h));
  strcpy(h.name, name);
  h.size = size;
  h.type = MTAR_TREG;
  h.mode = 0664;
  /* Write header */
  return mtar_write_header(tar, &h);
}