marshal complex structures to native C dll

  • Thread starter Thread starter Ivan
  • Start date Start date
I

Ivan

Hi All,

I have a problem with marshaling complex structures (containing numbers,
strings, arrays of another structures) to native C function in dll.
I have already posted same question to .compactframework thread, but nobody
helped.

main problem is that I have tried all the workarounds I have found in the
Inet but nothing worked...
I tried passing IntPtr, Byte Arrays, Serialisation, even used OpenNETCF, but
all failed.

I have even compiled own C dll (eVC 4.0) with same structures and functions,
and there I
can see what is passed in params and can return needed values. Result - the
structure I pass to the function is empty and the structure I return from
the function is not retrieved to outside (I have same structure that passed
to function with no changes)

any ideas?

I need to do it on VB.NET for Compact Framework

thanks in advance for any help.
Ivan.

--------------------

typedef struct tagACROSS_CLUE {
unsigned int numClue; /* Clue number */
LPCWSTR strClue; /* The clue - clue number not included in the string */
} ACROSS_CLUE;

typedef struct tagACROSS_EXTDATA {
unsigned char extDataSignature[4]; /* Four byte character signature */
unsigned int dataSize; /* Size of extended data in bytes */
char * extData; /* uninterpreted bytes of data */
} ACROSS_EXTDATA;

typedef struct tagACROSS_HEADER {
BYTE bytes[44]; /* Uninterpreted bytes from the header */
} ACROSS_HEADER;

typedef struct tagACROSS_PUZZLE_DATA {
unsigned int struct_size; /* size of the data structure passed in bytes
must be initialized */
unsigned int szAcross; /* Grid size - No. of cells across */
unsigned int szDown; /* Grid Size - No. of cells down */
unsigned int numAClues; /* Total No. of Across clues */
unsigned int numDClues; /* Total No. of Down clues */
int flagsDescr; /* Puzzle flags */
int numCodeSet; /* Character code set used for the puzzle */
unsigned int numPtrSolnKey; /* For saving, if solution is to be locked,
the 4 digit lock key is returned here For reading, this is not used */
LPCWSTR strTitle; /* Puzzle Title */
LPCWSTR strAuthor; /* Puzzle Author */
LPCWSTR strCopyright; /* Puzzle Copyright */
LPCWSTR charsGrid; /* Puzzle Grid with solution */
LPCWSTR strNote; /* Puzzle notepad entry. Max length 1023 characters */
ACROSS_CLUE * cluesAcross;/* Pointer to array of Across clues */
ACROSS_CLUE * cluesDown; /* Pointer to array of Down clues */
unsigned int numExtData; /* Number of extended data structures */
ACROSS_EXTDATA * extDataList; /* Pointer to array of extended data
structures */
} ACROSS_PUZZLE_DATA;

ACLIB_API int ACROSS_InputPuzzle(LPCWSTR filename,

ACROSS_PUZZLE_DATA * puzzleDescriptor);

/* filename - Complete path name of file to read puzzle from */

/* puzzleDescriptor - Pointer to structure that will contain puzzle
data. */
 
Hello,

I would recommend you to write another custom C dll wich
exports some sort of getters and setters for the structure.

LPWCSTR getTitle_PuzzleData(ACROSS_PUZZLE_DATA* data) {
return data->strTitle;
}

void setTitle_PuzzleDate(ACROSS_PUZZLE_DATA* data, LPWCSTR title) {
data->strTitle = title;
}

One the one hand you've got a great number of DllImports and
on the other a complex structure which has to be marshalled.

hth

Hi All,

I have a problem with marshaling complex structures (containing numbers,
strings, arrays of another structures) to native C function in dll.
I have already posted same question to .compactframework thread, but
nobody
helped.

main problem is that I have tried all the workarounds I have found in the
Inet but nothing worked...
I tried passing IntPtr, Byte Arrays, Serialisation, even used OpenNETCF,
but
all failed.

I have even compiled own C dll (eVC 4.0) with same structures and
functions,
and there I
can see what is passed in params and can return needed values. Result -
the
structure I pass to the function is empty and the structure I return from
the function is not retrieved to outside (I have same structure that
passed
to function with no changes)

any ideas?

I need to do it on VB.NET for Compact Framework

thanks in advance for any help.
Ivan.

--------------------

typedef struct tagACROSS_CLUE {
unsigned int numClue; /* Clue number */
LPCWSTR strClue; /* The clue - clue number not included in the
string */
} ACROSS_CLUE;

typedef struct tagACROSS_EXTDATA {
unsigned char extDataSignature[4]; /* Four byte character signature
*/
unsigned int dataSize; /* Size of extended data in bytes */
char * extData; /* uninterpreted bytes of data */
} ACROSS_EXTDATA;

typedef struct tagACROSS_HEADER {
BYTE bytes[44]; /* Uninterpreted bytes from the header */
} ACROSS_HEADER;

typedef struct tagACROSS_PUZZLE_DATA {
unsigned int struct_size; /* size of the data structure passed in
bytes
must be initialized */
unsigned int szAcross; /* Grid size - No. of cells across */
unsigned int szDown; /* Grid Size - No. of cells down */
unsigned int numAClues; /* Total No. of Across clues */
unsigned int numDClues; /* Total No. of Down clues */
int flagsDescr; /* Puzzle flags */
int numCodeSet; /* Character code set used for the puzzle */
unsigned int numPtrSolnKey; /* For saving, if solution is to be
locked,
the 4 digit lock key is returned here For reading, this is not used */
LPCWSTR strTitle; /* Puzzle Title */
LPCWSTR strAuthor; /* Puzzle Author */
LPCWSTR strCopyright; /* Puzzle Copyright */
LPCWSTR charsGrid; /* Puzzle Grid with solution */
LPCWSTR strNote; /* Puzzle notepad entry. Max length 1023 characters
*/
ACROSS_CLUE * cluesAcross;/* Pointer to array of Across clues */
ACROSS_CLUE * cluesDown; /* Pointer to array of Down clues */
unsigned int numExtData; /* Number of extended data structures */
ACROSS_EXTDATA * extDataList; /* Pointer to array of extended data
structures */
} ACROSS_PUZZLE_DATA;

ACLIB_API int ACROSS_InputPuzzle(LPCWSTR filename,

ACROSS_PUZZLE_DATA * puzzleDescriptor);

/* filename - Complete path name of file to read puzzle from */

/* puzzleDescriptor - Pointer to structure that will contain puzzle
data. */
Click to expand...
 
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