DPI-C import --- Returning string value from C with a "char **var" argument

SystemVerilog
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2

In reply to Luca Iovinella:

Most simulators will generate the correct header file for DPI calls. You can use this header file in your C code to ensure compatibility.

The correct C prototype is:

int my_dpi(const char arg, const char* ret);

Since the second argument is a pointer to a pointer, you need to de-reference it when it’s being assigned:

int my_dpi(const char *arg, const char **ret) {
printf(“DPI Received arg: %s\n”, arg);
*ret = “HELLO”;
return TRUE;
}

You need to ensure that anything returned back to the simulator has a suitable lifetime and isn’t destroyed on the C side as this may result in invalid data being returned.