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Delphi shielding ADO piece of code there is no problem, but with couldn't call
In the Delphi code:

 library ADSB; 

USES the 
ShareMem, SysUtils ADODB, DB, ActiveX, Windows, StrUtils, 
Classes; 
{$R *. Res} 
Const 
Connectionstr='Provider=SQLOLEDB. 1; Persist Security Info=False; User ID=sa; Initial Catalog=airline2; The Data Source=. '; 

The function aircraft (var FlightID: PChar) : PChar; Cdecl; Export; 
Var 
PType: string; 
Con1: TADOConnection; 
Qry1: TADOQuery; 
The begin 
CoInitialize (nil); 
Qry1:=TADOQuery. Create (nil); 
Con1:=TADOConnection. Create (nil); 
Qry1. Connection:=con1; 
Qry1. The ConnectionString:=connectionstr; 
Qry1. Close; 
Qry1. SQL. The Clear; 
Qry1. SQL. The Add (' select NO from routes where FN collate Chinese_PRC_CS_AS=: a '); 
Qry1. The Parameters. ParamByName (' a '). The Value:=StrPas (FlightID); 
Qry1. Open; 
If qry1. RecordCount> 0 then 
The begin 
PType:=qry1 Fields. [0] Value; 
end; 
Result:=PChar (PType); 
Qry1. Close; 
CoUninitialize; 
end; 

Exports 
Aircraft; 

The begin 

End. 

Vs the code is as follows:

 # include & lt; Windows. H> 
#include  
#include  
#include  
using namespace std; 
Typedef char * (* myFun) (char * arg1); 
Int main (int argi, char * argv []) 
{
HINSTANCE hDll; 
HDll=LoadLibrary (" ADSB. DLL "); 
If (hDll!=NULL) 
{
MyFun fun; 
Fun=(myFun) GetProcAddress call (hDll, "aircraft"); 
If (fun!=NULL) 
{
Char * p="AAF103"; 
Char * pl=fun (p); 
Cout} 
FreeLibrary (hDll); 
} 
system("pause"); 
return 0; 
} 

Beg you to see what a great god can help have a problem? Thank you very much!

CodePudding user response:

Prompt error as shown

CodePudding user response:

Some advice: don't use pchar as a function return value, and take them to the function of input parameters qry use don't use con the socket, a choice, use pchar want to apply for memory, can step through dynamic database, this is the basic skill,

CodePudding user response:

Can step through dynamic database, this is the basic skill,

CodePudding user response:

Con1 don't have to set the ConnectionString?
Qry1 need to set up the ConnectionString?


Qry1. The ConnectionString:=connectionstr;

The dynamic repository to step through the look on both sides of the position