function pointer translation - help needed

[Guest]

hi,
i tried to search for this translation problem, but couldn’t find anything.
maybe some one can tell me how the following code is translated to powerbasic.
i would need to know, how the function pointers are handled in powerbasic
in a translated structure and in a translated function call.

btw, is there a tool that will translate C headers to powerbasic include files?

thank you for any help

hans


typedef signed short ISC_SHORT;
typedef unsigned short ISC_USHORT;
typedef unsigned char ISC_UCHAR;
typedef char ISC_SCHAR;
typedef signed long ISC_LONG;
typedef unsigned long ISC_ULONG;

typedef void (* isc_callback) ();
typedef ISC_LONG isc_resv_handle;
typedef void (*ISC_PRINT_CALLBACK) (void*, ISC_SHORT, const char*);
typedef void (*ISC_VERSION_CALLBACK)(void*, const char*);
typedef void (*ISC_EVENT_CALLBACK) (void*, ISC_USHORT, const ISC_UCHAR*);

ISC_STATUS ISC_EXPORT isc_print_blr(const ISC_SCHAR*,

ISC_PRINT_CALLBACK,
void*,
short);

typedef struct blobcallback {

short (*blob_get_segment) (void* hnd, ISC_UCHAR* buffer, ISC_USHORT buf_size, ISC_USHORT* result_len);
void* blob_handle;
ISC_LONG blob_number_segments;
ISC_LONG blob_max_segment;
ISC_LONG blob_total_length;
void (*blob_put_segment)(void* hnd, const ISC_UCHAR* buffer, ISC_USHORT buf_size);
ISC_LONG (*blob_lseek)(void* hnd, ISC_USHORT mode, ISC_LONG offset);

} *BLOBCALLBACK;

[José Roca]

FUNCTION isc_callback() AS DWORD
END FUNCTION

FUNCTION isc_resv_handle() AS LONG
END FUNCTION

FUNCTION ISC_PRINT_CALLBACK(BYVAL p1 AS DWORD, BYVAL p2 AS INTEGER, BYREF p3 AS ASCIIZ) AS DWORD
END FUNCTION

FUNCTION ISC_VERSION_CALLBACK(BYVAL p1 AS DWORD, BYREF p2 AS ASCIIZ) AS DWORD
END FUNCTION

FUNCTION ISC_EVENT_CALLBACK(BYVAL p1 AS DWORD, BYVAL p2 AS WORD, BYREF p3 AS ASCIIZ) AS DWORD
END FUNCTION

DECLARE FUNCTION isc_print_blr LIB "<name of the dll>" ALIAS "isc_print_blr" ( _
   BYREF p1 AS ASCIIZ, BYVAL p2 AS DWORD, BYVAL p3 AS DWORD, BYVAL p4 AS WORD) AS LONG

TYPE BLOBCALLBACK
   fn_blob_get_segment AS DWORD
   fn_blob_handle AS DWORD
   fn_blob_number_segments AS DWORD
   fn_blob_max_segment AS DWORD
   fn_blob_total_length AS DWORD
   fn_blob_put_segment AS DWORD
   fn_blob_lseek AS DWORD
END TYPE

[Guest]

thank you very much for your help and advice!

hans

[José Roca]

If you have to use the pointers in the BLOBCALLBACK structure to call a function, then you can do it this way.

Declare a prototype for the function, e.g.

' ISC_LONG blob_number_segments;
DECLARE FUNCTION blob_number_segments() AS LONG

Use CALL DWORD with the pointer stored in the structure.

DIM nSegments AS LONG
CALL DWORD <name of the udt dimed AS BLOBCALLBACK>.fn_blob_number_segments USING blob_number_segments TO nSegments

[Guest]

thank you.
yes i think i need to use it as pointers. is there any tool that will translate, for example the firebird headers, atleast semi automatic? this is a lot of work for somebody new that is to PB.

btw, i applied for you board.

thanks again

hans

[José Roca]

None that does a good job. It is very difficult because C uses many typedefs, macros and weird syntaxes.

Your account has been approved. Sorry for the delay.

[Guest]

thank you!!

hans