a structure with a vector as a member

[AfricanDude]

Hello:
I have this interesting problem...
I have to use a c-library that contains a function that is defined as follow:

int func(char * cpData);

I have been using a structure accually a nested structure as follows

struct A
{
char cString;
char cAnotherstring;
}sA;

struct B
{
int iIndex;
float fData[MAXDATA];

}sB;

struct C
{
struct A nA;
struct B nB[8];

}sStream;


I can call this structure with now problems
using func((char *) &sStream);


I wanted to use a vector for the float fData

such as the struct B is as follows:

struct B
{
int iIndex;
vector< float> fData;
} sB;


when I call the function I getting garbaged data.
I do take care of reserving the data size.
In fact I can see that the correct data iscorrect, just prior to calling
this legecy function.

Is there a way I can convert somehow to c-array which the function understands
but be able to take advantage of the vector.

Your speedy reply wiill be vey much appreciated.

AD

[wien]

I already answered this question in the other thread you had going. Maybe a mod could flip my post over here since the question/answer is not really related to that thread.

[AfricanDude]

As you see I have to use a c library, and I can not do what you are suggesting
can I, I geuss May be I do not understand what you have said.
Could you elaborate more.

Thanx

AD

[wien]

Well.. You are using a std::vector, so you're obiously on C++. If you serialize your struct using >>, << and std::ostream (std::ostringstream to be specific), you can still plug the result of that operation into a C function by getting a std::string of the stream (str() member-function), and passing that string to the C-function using std::string's c_str() member-function.

[wien]

Note that you won't get the binary representation of the struct by using std::ostream though. Only a textual representation. If you need the binary representation, you will have to write your own serializer. I did write one myself a while back, and I would have shared, if only I could find it.

[AfricanDude]

That is over my head for now.
But I will chew on it for a while
Thank you for yor time

AD

[wien]

Reccomended reading: http://www.parashift.com/c++-faq-lit...alization.html