Hi, I've been trying to use boost::tuple with a boost::optional element and
I get a bad::cast exception. Attached to this mail you can find the
complete test case but here is small code snippet:
That works:
row_type get_last_row(soci::session& sql)
{
unsigned int id = 0;
std::string str1;
boost::optional<std::string> str2;
sql << "SELECT id, str1, str2 from example ORDER BY id DESC LIMIT 1",
soci::into(id), soci::into(str1), soci::into(str2);
return row_type(id, str1, str2);
}
That does not:
row_type get_last_row2(soci::session& sql)
{
row_type myrow;
try
{
sql << "SELECT id, str1, str2 from example ORDER BY id DESC LIMIT 1",
soci::into(myrow);
}
catch(const std::exception& e)
{
std::cout << "Exception: " << e.what() << std::endl;
}
return myrow;
}
Probably i'm missing something, but I can't find it.
Thanks in advance.
#include <boost/tuple/tuple.hpp>
#include <boost/optional.hpp>
#include <iostream>
#include <exception>
#define SOCI_USE_BOOST
#include "soci.h"
#include "boost-optional.h"
#include "boost-tuple.h"
#include "sqlite3/soci-sqlite3.h"
typedef boost::tuple<
unsigned int,
std::string,
boost::optional<std::string>
> row_type;
row_type get_last_row(soci::session& sql)
{
unsigned int id = 0;
std::string str1;
boost::optional<std::string> str2;
sql << "SELECT id, str1, str2 from example ORDER BY id DESC LIMIT 1",
soci::into(id), soci::into(str1), soci::into(str2);
return row_type(id, str1, str2);
}
row_type get_last_row2(soci::session& sql)
{
row_type myrow;
try
{
sql << "SELECT id, str1, str2 from example ORDER BY id DESC LIMIT 1",
soci::into(myrow);
}
catch(const std::exception& e)
{
std::cout << "Exception: " << e.what() << std::endl;
}
return myrow;
}
int main()
{
soci::session sql(*soci::factory_sqlite3(), ":memory:");
sql << "CREATE TEMP TABLE example("
" id INTEGER PRIMARY KEY AUTOINCREMENT,"
" str1 TEXT,"
" str2 TEXT DEFAULT NULL"
")";
sql << "INSERT INTO example(id, str1, str2)"
" VALUES(NULL, datetime('now'), NULL)";
row_type myrow = get_last_row(sql);
std::cout << myrow.get<0>() << std::endl;
std::cout << myrow.get<1>() << std::endl;
std::cout << std::boolalpha << myrow.get<2>().is_initialized() << std::endl;
row_type myrow2 = get_last_row2(sql);
std::cout << myrow2.get<0>() << std::endl;
std::cout << myrow2.get<1>() << std::endl;
std::cout << std::boolalpha << myrow2.get<2>().is_initialized() << std::endl;
return 0;
}
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