I'm trying to pass pointers to two `struct timevals` to a function that would output the elapsed time between the two in a C program. However, even if I dereference these pointers, nvcc throws the error "expression must have class type" (this is a CUDA program). Here is the relevant code from main(): struct timeval begin, end; if (tflag) { HostStartTimer(&begin) }; // CUDA Kernel execution if (tflag) { HostStopTimer(&begin, &end); } And the function definition for HostStopTimer(): void HostStopTimer(struct timeval *begin, stuct timeval *end) { long elapsed; gettimeofday(end, NULL); elapsed = ((*end.tv_sec - *begin.tv_sec)*1000000 + *end.tv_usec - *begin.tv_usec); printf("Host elapsed time: %ldus\n", elapsed); } The line causing the error is the assignment to `elapsed`. I don't have much experience using structs in C, much less passing pointers to structs to functions, so I'm not sure what is causing the error.