The complexity of calling an unmanaged dll from C #

Question

I'm going crazy trying to figure out why I can't call an external method in old C ++. Dll from my C # application.

Here's the function header:

int __export FAR PASCAL SimplePGPEncryptFile(
                                      HWND hWnd1,
                                      LPSTR InputFileName,
                                      LPSTR OutputFileName,
                                      BOOL SignIt,
                                      BOOL Wipe,
                                      BOOL Armor,
                                      BOOL TextMode,
                                      BOOL IDEAOnly,
                                      BOOL UseUntrustedKeys,
                                      LPSTR RecipientList,
                                      LPSTR SignerKeyID,
                                      int SignerBufferLen,
                                      LPSTR SignerPassphrase,
                                      int SignerPwdBufferLen,
                                      LPSTR IDEAPassphrase,
                                      int IDEAPwdBufferLen,
                                      LPSTR PublicKeyRingName,
                                      LPSTR PrivateKeyRingName);

Here is my C # declaration:

        [DllImport("smplpgp_32.dll", CallingConvention = CallingConvention.StdCall)]
    public static extern int SimplePGPEncryptFile(
        IntPtr hWnd1,
        [MarshalAs(UnmanagedType.LPStr)] string InputFileName,
        [MarshalAs(UnmanagedType.LPStr)] string OutputFileName,
        bool SignIt,
        bool Wipe,
        bool Armor,
        bool TextMode,
        bool IDEAOnly,
        bool UseUntrustedKeys,
        [MarshalAs(UnmanagedType.LPStr)] string RecipientList,
        [MarshalAs(UnmanagedType.LPStr)] string SignerKeyID,
        int SignerBufferLen,
        [MarshalAs(UnmanagedType.LPStr)] string SignerPassphrase,
        int SignerPwdBufferLen,
        [MarshalAs(UnmanagedType.LPStr)] string IDEAPassphrase,
        int IDEAPwdBufferLen,
        [MarshalAs(UnmanagedType.LPStr)] string PublicKeyRingName,
        [MarshalAs(UnmanagedType.LPStr)] string PrivateKeyRingName);

When I call this method, I get one of the following two errors (declared in the header):

#define SIMPLEPGPENCRYPTFILE_RECIPIENTLISTDOESNOTENDWITHNEWLINE    408
#define SIMPLEPGPENCRYPTFILE_RECIPIENTLISTDOESNOTSTARTWITHGOODCODECHAR   409

It is also defined as a constant in the header:

#define INCLUDE_ONLYUSERIDS 1

This is C ++ code, which, as you know, works when this function is called:

    char recipients[512];
recipients[0] = INCLUDE_ONLYUSERIDS;
strcat(strcpy(&recipients[1], rID), "\n"); \\ rID is equal to "CA"
return 0 == SimplePGPEncryptFile(INI.m_hWnd,
    (char*)plain, (char*)cipher,
    0,
    0,
    1,
    0,
    0,
    1, // UseUntrustedKeys
    recipients,
    0, 0,
    0, 0,
    0, 0,
    PGPKM.pub, 0); //PGPKM.pub is declared earlier

Passing this parameter "RecipientList" gives me error "409":

string recipientList = "1CA\n\0";

Passing this parameter "RecipientList" gives me the error "408":

char[] recipients = new char[512];
recipients[0] = '1';
recipients[1] = 'C';
recipients[2] = 'A';
recipients[3] = '\n'; // also tried '\r', then '\n'
recipients[4] = Char.MinValue;
string paramValue = recipients.ToString();

Can anyone notice overt supervision on my part? I feel like I have everything I need to solve this, but nothing works as expected.

: DLL. , StringBuilder RecipientList.

!

Answer 1

TL;DR:

string recipientList = (char) 1 + "CA\n\0";

- ... , , , , . , :

:

string recipientList = "1CA\n\0";

, LPStr, :

49-67-65-10-0

, .

:

char[] recipients = new char[512];
recipients[0] = '1';
recipients[1] = 'C';
recipients[2] = 'A';
recipients[3] = '\n'; // also tried '\r', then '\n'
recipients[4] = Char.MinValue;
string paramValue = recipients.ToString();

, LPStr:

83-121-115-116-101-109-46-67-104-97-114-91-93

ASCII "System.Char []". , char [] .

, ... , DLL "1", ascii "1" (49). , , :

recipients[0] = INCLUDE_ONLYUSERIDS;

INCLUDE_ONLYUSERIDS = 1

:

string recipientList = (char) 1 + "CA\n\0";

:
, , Char.ToString() char , LPStr, LPWStr. LPStr ANSII.

, .

byte[] recipients= new byte[512];
 ...
//  Pass this string to SimplePGPEncryptFile
string recipientsToPass = System.Text.ASCIIEncoding.ASCII.GetString(recipients);

Answer 2

? ++ pascal # stdcall. .