On Tuesday, 6 December 2022 at 23:41:09 UTC, H. S. Teoh wrote:
On Tue, Dec 06, 2022 at 11:07:32PM +0000, johannes via
Digitalmars-d-learn wrote:
//-- the result should be f.i. "the sun is shining"
//-- sqlite3_column_text returns a constant char* a \0
delimited c-string
printf("%s\n",sqlite3_column_text(res, i));
writeln(sqlite3_column_text(res, i));
[...]
In D, strings are not the same as char*. You should use
std.conv.fromStringZ to convert the C char* to a D string.
T
no, you don't "need" to use std conv
Here is an alternative that doesn't allocate
Make sure to read the comments
```D
// here notice where the functions are comming from
import std.stdio : writeln, writefln;
import core.stdc.stdio : printf;
import core.stdc.string : strlen;
const(char)* sqlite3_column_text(void*, int iCol)
{
return "hello world";
}
void main()
{
// printf is a libc function, it expects a null terminated
string (char*)
printf("%s\n", sqlite3_column_text(null, 0));
// writeln is a d function, it expects a string (immutable
slice of char aka immutable(char)[], a slice is T* + len)
// so here we get the string from sqlite
const(char)* ret = sqlite3_column_text(null, 0);
// then we need to determine the length of the null
terminated string from c
// we can use strlen from libc
size_t len = strlen(ret);
// now we got a len, we can build a D string, remember, it's
just a slice
string str = cast(string) ret[0 .. len];
writeln(str);
writefln("%s", str);
}
```
