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digitalmars.D.learn - problem creating a berkeley db binding

reply JT <jt nomail.com> writes:
i'm trying to create a binding for berkeley db dll and quickly ran into some
problems, how do i translate statement below.

int DB->open(DB *db, DB_TXN *txnid, const char *file,
    const char *database, DBTYPE type, u_int32_t flags, int mode);

my normal approach would be,

extern (C) {
	int function(DB* db, DB_TXN* txnid, char* file, char* database, DBTYPE type,
u_int32_t flags, int mode) DB->open;
}

but real problem is 'DB->open', can anoybody suggest a workaround for this. DB
is just a simple struct (struct DB;)
Aug 30 2009
next sibling parent reply Sergey Gromov <snake.scaly gmail.com> writes:
Sun, 30 Aug 2009 11:28:16 -0400, JT wrote:


 i'm trying to create a binding for berkeley db dll and quickly ran
 into some problems, how do i translate statement below.
 
 int DB->open(DB *db, DB_TXN *txnid, const char *file,
     const char *database, DBTYPE type, u_int32_t flags, int mode);


This is not a valid C or C++ statement, nor a declaration.  It's usually
hard to translate an invalid code to a different language.


 my normal approach would be,
 
 extern (C) {
 	int function(DB* db, DB_TXN* txnid, char* file, char* database, DBTYPE type,
u_int32_t flags, int mode) DB->open;
 }


If open() is a method of DB struct then it uses some sort of C++ calling
convention, probably thiscall.  Thiscall is incompatilbe with cdecl, so
extern(C) won't work.


 but real problem is 'DB->open', can anoybody suggest a workaround for
 this. DB is just a simple struct (struct DB;)


I can only guess here that what you want is

extern(C++) interface DB {
    int open(DB_TXN* txnid, char* file, char* database, DBTYPE type, u_int32_t
flags, int mode);
}

But, without a link to source you try to bind to, it's only a wild
guess.
Aug 30 2009
parent JT <jt nomail.com> writes:
Sergey Gromov Wrote:


 Sun, 30 Aug 2009 11:28:16 -0400, JT wrote:
 

 i'm trying to create a binding for berkeley db dll and quickly ran
 into some problems, how do i translate statement below.
 
 int DB->open(DB *db, DB_TXN *txnid, const char *file,
     const char *database, DBTYPE type, u_int32_t flags, int mode);


 
 This is not a valid C or C++ statement, nor a declaration.  It's usually
 hard to translate an invalid code to a different language.
 

 my normal approach would be,
 
 extern (C) {
 	int function(DB* db, DB_TXN* txnid, char* file, char* database, DBTYPE type,
u_int32_t flags, int mode) DB->open;
 }


 
 If open() is a method of DB struct then it uses some sort of C++ calling
 convention, probably thiscall.  Thiscall is incompatilbe with cdecl, so
 extern(C) won't work.
 

 but real problem is 'DB->open', can anoybody suggest a workaround for
 this. DB is just a simple struct (struct DB;)


 
 I can only guess here that what you want is
 
 extern(C++) interface DB {
     int open(DB_TXN* txnid, char* file, char* database, DBTYPE type, u_int32_t
flags, int mode);
 }
 
 But, without a link to source you try to bind to, it's only a wild
 guess.


thanks, unfortunately the source is too long to include here, it was a Berkeley
DB from Oracle. is there a binding already made for this library. :P
Aug 30 2009
prev sibling next sibling parent reply Mike Parker <aldacron gmail.com> writes:
JT wrote:

 i'm trying to create a binding for berkeley db dll and quickly ran into some
problems, how do i translate statement below.
 
 int DB->open(DB *db, DB_TXN *txnid, const char *file,
     const char *database, DBTYPE type, u_int32_t flags, int mode);
 
 my normal approach would be,
 
 extern (C) {
 	int function(DB* db, DB_TXN* txnid, char* file, char* database, DBTYPE type,
u_int32_t flags, int mode) DB->open;
 }
 
 but real problem is 'DB->open', can anoybody suggest a workaround for this. DB
is just a simple struct (struct DB;)


The function name is not 'DB->open'. That's something used in the 
comments. Nearly all functions in Berkeley DB are declared as function 
pointers used as struct fields. So what you'll want is something like this:

extern(C):

struct DB
{
     int function(DB* db, DB_TXN* txnid, char* file, char* database, 
DBTYPE type, u_int32_t flags, int mode) open;
}

Along with all of the rest of the DB function pointers and the numerous 
inner structs declared in the C headers.
Aug 31 2009
parent JT <jt nomail.com> writes:
Mike Parker Wrote:


 JT wrote:

 i'm trying to create a binding for berkeley db dll and quickly ran into some
problems, how do i translate statement below.
 
 int DB->open(DB *db, DB_TXN *txnid, const char *file,
     const char *database, DBTYPE type, u_int32_t flags, int mode);
 
 my normal approach would be,
 
 extern (C) {
 	int function(DB* db, DB_TXN* txnid, char* file, char* database, DBTYPE type,
u_int32_t flags, int mode) DB->open;
 }
 
 but real problem is 'DB->open', can anoybody suggest a workaround for this. DB
is just a simple struct (struct DB;)


 
 The function name is not 'DB->open'. That's something used in the 
 comments. Nearly all functions in Berkeley DB are declared as function 
 pointers used as struct fields. So what you'll want is something like this:
 
 extern(C):
 
 struct DB
 {
      int function(DB* db, DB_TXN* txnid, char* file, char* database, 
 DBTYPE type, u_int32_t flags, int mode) open;
 }
 
 Along with all of the rest of the DB function pointers and the numerous 
 inner structs declared in the C headers.


thank you so much Mike. yeah i just noticed that.
Aug 31 2009
prev sibling parent BLS <windevguy hotmail.de> writes:
JT wrote:

 i'm trying to create a binding for berkeley db dll and quickly ran into some
problems, how do i translate statement below.
 
 int DB->open(DB *db, DB_TXN *txnid, const char *file,
     const char *database, DBTYPE type, u_int32_t flags, int mode);
 
 my normal approach would be,
 
 extern (C) {
 	int function(DB* db, DB_TXN* txnid, char* file, char* database, DBTYPE type,
u_int32_t flags, int mode) DB->open;
 }
 
 but real problem is 'DB->open', can anoybody suggest a workaround for this. DB
is just a simple struct (struct DB;)


Maybe this project is interesting. last update may 2007

http://code.google.com/p/db4d/
Sep 03 2009