168. Calling the strcat() foreign function

The strcat() foreign function is part of the C standard library and has the following signature (https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/strcat-wcscat-mbscat):

char *strcat(char *strDestination, const char *strSource);

This function appends the strSource at the end of the strDestination. The function doesn’t get these strings. It gets two pointers to these strings (so, two ADDRESS) and doesn’t return a value, so we rely on FunctionDescriptor.ofVoid(), as follows:

Linker linker = Linker.nativeLinker();
SymbolLookup libLookup = linker.defaultLookup();
try (Arena arena = Arena.ofConfined()) {
  MemorySegment segmentStrcat
    = libLookup.find("strcat").get();
  MethodHandle func = linker.downcallHandle(
    segmentStrcat, FunctionDescriptor.ofVoid(
      ValueLayout.ADDRESS, ValueLayout.ADDRESS));
  ...

Since the arguments of strcat() are two pointers (ADDRESS), we have to create...