#include <cstdio>
#include <string>
#define MAX_LEN 512
int main()
{
std::string imageFileName = "/image/file/name";
imageFileName.resize(MAX_LEN);
// ...
if (int len = (imageFileName.size() >= MAX_LEN))
{
printf("File path %s is too long (max len: %d): %d\n",
imageFileName.c_str(), MAX_LEN, len);
return EXIT_FAILURE;
}
printf("File path %s is valid\n", imageFileName.c_str());
// ...
}