Memory returned by NTDIRECT.DLL Orders, and use of SetAllocReturnString arguments

[douggreen]

I'm calling SetAllocReturnString and SetMaxReturnStringLength from a DLL and would like to know what the arguments to SetAllocReturnString do.

Mostly though, I'd like to know if the memory returned by Orders needs to be freed in my DLL (if I don't return that string to TradeStation) or if I should possibly use a different argument than SetAllocReturnString(1) so I don't need to free the memory. I tried calling free() on this string and threw an exception.

[NinjaTrader_Dexter]

Hello douggreen,

Thank you for your post.

SetAllocReturnString() parameters are as follows:
0 = string is written to a static buffer, overwriting any previous string at this buffer
1 = a new memory buffer is allocated for each returned string

TS may try to free the memory for strings returned from the NTDirect dll. Note, the wrapper NT functions in the ELD file will set SetAllocReturnString for you. If you need to set it manually for some reason though, you would want to use SetAllocReturnString(1) in case TS tries to free it.

If you are using the DLL outside of TS and are using SetAllocReturnString(1), you would be expected to free the memory in your code or else you will introduce a memory leak as NTDirect.dll will not take care of these dynamic memory buffers. It may be more ideal to use the 0 parameter in this case.

Please see this forum post for a full description of the function and how the string memory buffers are managed: http://www.ninjatrader.com/support/f...ad.php?t=39988 .

Please let me know if I can assist any further.