shared.c

// cc -o shared shared.c -lsqlite3 && ./shared

#include <stdio.h>
#include <sqlite3.h>

#if 0
#define path ":memory:"
#elif 0
#define path "file:memdb?cache=shared"
#elif 1
#define path "file:memdb?mode=memory&cache=shared"
#endif

int main(int argc, char** argv) {
  sqlite3* db = NULL;
  int rc = sqlite3_open_v2(path, &db,
                           SQLITE_OPEN_URI|SQLITE_OPEN_SHAREDCACHE|
                           SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE, NULL);
  if (rc != SQLITE_OK) {
    fprintf(stderr, "sqlite3_open_v2() -> %d\n", rc);
    return 1;
  }

  char* errmsg = NULL;
#if 0
  rc = sqlite3_exec(db, "CREATE TABLE t (c TEXT)", NULL, NULL, &errmsg);
#else
  rc = sqlite3_exec(db, "CREATE VIRTUAL TABLE t USING fts3(c TEXT)", NULL, NULL, &errmsg);
#endif
  if (rc != SQLITE_OK) {
    fprintf(stderr, "CREATE -> %d:%s\n", rc, errmsg);
    return 1;
  }

  rc = sqlite3_exec(db, "INSERT INTO t VALUES ('hello')", NULL, NULL, &errmsg);
  if (rc != SQLITE_OK) {
    fprintf(stderr, "INSERT -> %d:%s\n", rc, errmsg);
    return 1;
  }

  sqlite3* odb = NULL;
  rc = sqlite3_open_v2(path, &odb,
                       SQLITE_OPEN_URI|SQLITE_OPEN_SHAREDCACHE|
                       SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE, NULL);
  if (rc != SQLITE_OK) {
    fprintf(stderr, "other sqlite3_open_v2() -> %d\n", rc);
    return 1;
  }

  sqlite3_stmt* s = NULL;
  rc = sqlite3_prepare(odb, "SELECT c FROM t", -1, &s, NULL);
  if (rc != SQLITE_OK) {
    fprintf(stderr, "prepare -> %d\n", rc);
    return 1;
  }

  rc = sqlite3_step(s);
  if (rc != SQLITE_ROW) {
    fprintf(stderr, "first step -> %d\n", rc);
    return 1;
  }

  const unsigned char* t = sqlite3_column_text(s, 0);
  fprintf(stderr, "Got %s\n", t);

  rc = sqlite3_step(s);
  if (rc != SQLITE_DONE) {
    fprintf(stderr, "last step -> %d\n", rc);
    return 1;
  }

  fprintf(stderr, "Success\n");
  return 0;
}