On Jun 29, 2008, at 8:02 PM, Soul Boy wrote:
> This goes in a file called Test.h
...cut...paste...hack...
The problem can be demonstrated with much fewer lines:
---------- 8< -------- cut here --------- 8< -----------
#include <mysql++.h>
#include <ssqls.h>
#include <iostream>
sql_create_1(Test, 1, 0, mysqlpp::String, A);
int main()
{
std::string a("foo");
Test newRow(mysqlpp::String(a));
std::cout << newRow.table() << std::endl;
return 0;
}
---------- 8< -------- cut here --------- 8< -----------
This isn't specific to table(). You can get the same error trying to
print out newRow.A.
It's unrelated to Query, too. Query::insert() merely accesses
elements of the SSQLS.
It's probably not a compiler bug: I've seen essentially the same error
in g++ 4.0, g++ 4.2, plus VC++ 2008.
If you change the first two lines of main() to:
Test newRow(mysqlpp::String(std::string("foo")));
...the error goes away. (That is, make the temporary string implicit.)
I don't think this is a MySQL++ problem. It feels like some weird C++
parsing issue. Since multiple new-model compilers give the same
error, it's probably a "feature" of C++ in some demented way.
Unless you're using BLOBs, this problem is easily fixed: use
std::string in your SSQLSes, not mysqlpp::String. As it says in the
docs, mysqlpp::String is not a general-purpose string type. The only
reason end-user code should ever see mysqlpp::String directly is in
dealing with BLOBs.
If you are indeed using BLOBs, you can probably work around the
problem by reordering the parameters in your SSQLS. I found it to
happen with mysqlpp::DateTime, too, when that's first in the SSQLS.
But, you'll notice that examples/stock.h doesn't give this error,
since the sdate member is second to last.
More generally, you should be using the data types in lib/sql_types.h
when defining SSQLSes. So, mysqlpp::sql_blob instead of
mysqlpp::String, mysqlpp::sql_char instead of std::string...
