softdevice_enable returns error code 2

[telemedcar]

Hello,

I am using SoftDevice V4.0.3 and nRF52832.

In this code snipet I got the error code 2 when trying to enable SoftDevice :

int main (void) {

ret_code_t err_code;

uint32_t ram_start = 0;
error_code = softdevice_app_ram_start_get(&ram_start);
APP_ERROR_CHECK(err_code);

error_code = softdevice_enable(&ram_start);
APP_ERR_CHECK(err_code);

}

What does this error code mean and did I forget to initialize something ?

Best regards,

[telemedcar]

Actually I just want to enable SoftDevice to use the SoC library and did not therefore configure any BLE stack role. Can I do that ?