copy struct to buffer

[tom]

how to copy struct to buffer?

char * buffer;
buffer=(char *)malloc(5*20);
Data_O tt;
strcpy(tt.Name1 , "John ");
strcpy(tt.Name2 , "Brown ");
memcpy(buffer + 0,(const void*)tt, sizeof (tt)); // dasn't work
strcpy(tt.Name1 , "Tom ");
strcpy(tt.Name2 , "Backer ");
memcpy(buffer + 5,(const void*)tt, sizeof (tt)); // dasn't work
....

struct Data_O
{
char Name1[10+1];
char Name2[10+1];
};
t.

[Krishanu Debnath]

tom wrote:

how to copy struct to buffer?

char * buffer;
buffer=(char *)malloc(5*20);
Data_O tt;
strcpy(tt.Name1 , "John ");
strcpy(tt.Name2 , "Brown ");

Try this:

memcpy(buffer, &tt, sizeof tt);

memcpy(buffer + 0,(const void*)tt, sizeof (tt)); // dasn't work
strcpy(tt.Name1 , "Tom ");
strcpy(tt.Name2 , "Backer ");
memcpy(buffer + 5,(const void*)tt, sizeof (tt)); // dasn't work

memcpy(buffer + sizeof tt, &tt, sizeof tt);

Krishanu

[heltena]

char * buffer;
buffer=(char *)malloc(5*20);
Data_O tt;
strcpy(tt.Name1 , "John ");
strcpy(tt.Name2 , "Brown ");
memcpy(buffer + 0,(const void*)tt, sizeof (tt)); // dasn't work

tt is not a pointer, you must be use &tt.

strcpy(tt.Name1 , "Tom ");
strcpy(tt.Name2 , "Backer ");
memcpy(buffer + 5,(const void*)tt, sizeof (tt)); // dasn't work

Why not buffer + sizeof(tt) ?

Or:

char* buffer = new char[5 * sizeof(Data_O) ];
Data_O* tt = (Data_O*) buffer;
strcpy(tt->Name1, "John..");
strcpy(tt->Name2, "Brown");
tt = (Data_O*) (buffer + sizeof(Data_O)) ;
strcpy(tt->Name1, "Tom");
strcpy(tt->Name2, "Backer");
....
delete[] buffer;