File I/O

[Bruce Peaslee]

I'm getting to the point where some I/O would be useful. Maybe a short example?ÂÃ,  ÂÃ, 

Also, FileRequest() returns type HEAP. How does that work?

Thanks.

[Ionic Wind Support Team]

See editor.src.  Uses file I/O.  Or ask a specific question

HEAP is the same as string.  It is just dynamically allocated, the compiler handles it internally.

[Bruce Peaslee]

See editor.src.ÂÃ,  Uses file I/O.ÂÃ,  Or ask a specific question

Duh.ÂÃ,  :-[ÂÃ,  I was just studying it, too.

HEAP is the same as string.ÂÃ,  It is just dynamically allocated, the compiler handles it internally.

Got it.

[Parker]

I assume that HEAP is the same as in IB, where it works like this:

Code Select Expand

pointer pMem;
pMem = AllocHeap(6);
*(string)pMem = "Hello"; // five characters plus the null
return *(string)pMem;

And then anything that uses that function, the compiler will call FreeHeap after the statement is done executing. I do wonder though, how it's different to return the type STRING rather than HEAP, what the compiler does differently.

[Ionic Wind Support Team]

Use heap when the length of the returned string is an unknown at compile time.   Returning a string does the same memory management but the length of the string itself is fixed.

FileRequest can return an unlimited amount of multiple selected filenames.  A string or dstring type wouldn't work since we don't know how many files a user is going to select, and you wouldn't want a limit on that.

[Bruce Peaslee]

Here's a question. How do I read/write by UDT to disk?

[Ionic Wind Support Team]

write(file, udt, len(udt));
read(file, udt, len(udt));

use SEEK for positioning.

//read the 4th record
seek(file, len(udt) * 3);
reac(file, udt, len(udt);