How to pass char* arguments to DLL

Hello,

I loaded a DLL into Matlab via "loadlibrary". There is a C function prototyp with a filepath like:

extern "C" int LoadFile (const char* path);

This function appears in my mfile like:

fcns.name{fcnNum}='LoadFile '; fcns.calltype{fcnNum}='cdecl'; fcns.LHS{fcnNum}='int32'; fcns.RHS{fcnNum}={'uint8Ptr'};fcnNum=fcnNum+1;

How can i create a valid pointer with the filepath?

I tried:

ptr = libpointer('uint8Ptr','a.xsn')

which leads to an error.

Any help would be great. Best regards.