On Thursday, 22 March 2018 at 12:53:23 UTC, Martin Tschierschke
wrote:
On Wednesday, 21 March 2018 at 17:12:07 UTC, Timoses wrote:
[...]
I got it, my first mini test with C bindings!
Important missing at first: (stderr)
import core.stdc.stdio : stderr, FILE;
and use of toStringz inside: mapi_query(dbh, toStringz(q) )
After installing monetdb and starting the server with:
https://www.monetdb.org/Documentation/UserGuide/Tutorial
My minimal version of the example compiled with
dmd app.d -I /usr/local/lib/libmapi.so
(My dub.json is still incomplete so the linking failed.)
Here is the code: (only the minimum of mapi.h is icluded!)
```
std.stdio;
import std.string;
/* interfacing winth monetdb #include mapi.h */
/* minimum to run code of example at:
https://www.monetdb.org/Documentation/Manuals/SQLreference/Programming/MAPI */
import core.stdc.stdio : stderr,FILE;
import core.stdc.stdlib;
struct MapiStruct;
alias Mapi = MapiStruct*;
struct MapiStatement;
alias MapiHdl = MapiStatement*;
enum MOK = 0 ;
alias MapiMsg = int;
extern(System){
Mapi mapi_connect(const char* host, int port, const char*
username, const char* password, const char* lang, const char*
dbname);
MapiHdl mapi_query(Mapi mid, const char *cmd);
int mapi_fetch_row(MapiHdl hdl);
char *mapi_fetch_field(MapiHdl hdl, int fnr);
MapiMsg mapi_error(Mapi mid);
MapiMsg mapi_explain(Mapi mid, FILE* fd);
MapiMsg mapi_destroy(Mapi mid);
MapiMsg mapi_close_handle(MapiHdl hdl);
MapiMsg mapi_explain_result(MapiHdl hdl, FILE* fd);
MapiMsg mapi_next_result(MapiHdl hdl);
MapiMsg mapi_explain_query(MapiHdl hdl, FILE* fd);
char *mapi_result_error(MapiHdl hdl);
}
void die(Mapi dbh, MapiHdl hdl) {
if (hdl != null) {
mapi_explain_query(hdl, stderr);
do {
if (mapi_result_error(hdl) != null)
mapi_explain_result(hdl, stderr);
} while (mapi_next_result(hdl) == 1);
mapi_close_handle(hdl);
mapi_destroy(dbh);
} else if (dbh != null) {
mapi_explain(dbh, stderr);
mapi_destroy(dbh);
} else {
fprintf(stderr, "command failed\n");
}
exit(-1);
}
MapiHdl query(Mapi dbh, string q) {
MapiHdl ret = null;
if ((ret = mapi_query(dbh, toStringz(q) )) == null ||
mapi_error(dbh) != MOK)
die(dbh, ret);
return(ret);
}
void update(Mapi dbh, string q) {
MapiHdl ret = query(dbh, q);
if (mapi_close_handle(ret) != MOK)
die(dbh, ret);
}
void main()
{
auto dbh = mapi_connect("localhost", 50000, "monetdb",
"monetdb", "sql", "voc");
writeln("DB-connect");
update(dbh, "CREATE TABLE emp (name VARCHAR(20), age INT)");
writeln("create");
update(dbh, "INSERT INTO emp VALUES ('John', 23)");
update(dbh, "INSERT INTO emp VALUES ('Mary', 22)");
auto hdl = query(dbh, "SELECT * FROM emp");
while (mapi_fetch_row(hdl)) {
auto name = mapi_fetch_field(hdl, 0);
auto age = mapi_fetch_field(hdl, 1);
printf("%s is %s\n", name, age);
}
}
```
Will try to make a complete binding available later...
