Multi-line macro results in "Expected a Declaration" error - c++

Question

I am trying to use CUDA C for GPU computing, in particular matrix inversion problem. Meanwhile at the beginning of my code I have defined function. But, that seems to give me an error of "expected declation" at the line where I initiate "do".
I am new to C++ so haven't tried much.
#include<cublas_v2.h>
#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#define cudacall(call)
do
{
cudaError_t err = (call);
if (cudaSuccess != err)
{
fprintf(stderr, "CUDA Error:\nFile = %s\nLine = %d\nReason = %s\n", __FILE__, __LINE__, cudaGetErrorString(err));
cudaDeviceReset();
exit(EXIT_FAILURE)
}
}
while (0);
"Expected Declaration"

Answer 1

Multi-line macros need to have a \ to indicate that they continue on the next line. I lined all of them up at the end; scroll to see them.
#define cudacall(call) \
do { \
cudaError_t err = (call); \
if (cudaSuccess != err) { \
fprintf(stderr, "CUDA Error:\nFile = %s\nLine = %d\nReason = %s\n", \
__FILE__, __LINE__, cudaGetErrorString(err)); \
cudaDeviceReset(); \
exit(EXIT_FAILURE) \
} \
} while (0);
In general, please avoid macros if you can. Use lambdas and higher-order functions instead:
template<class F>
void cudacall(F&& func) {
cudaError_t err = func();
if (cudaSuccess != err) {
fprintf(stderr, "CUDA Error:\nFile = %s\nLine = %d\nReason = %s\n",
__FILE__, __LINE__, cudaGetErrorString(err));
cudaDeviceReset();
exit(EXIT_FAILURE);
}
}
We can use it like this:
void dostuff() {
bool wasICalled = false;
cudacall([&]() {
// Code goes here
// We can access and modify local variables inside a lambda
wasICalled = true;
// Return the error
return cudaError_t{};
});
}