Creating the environment

After declaring the necessary program variables, the example continues by creating an environment:

  error = GRBloadenv(&env, "mip1.log");
  if (error || env == NULL) {
    fprintf(stderr, "Error: could not create environment\n");
Later requests to create optimization models will always require an environment, so environment creation should always be the first step when using the Gurobi optimizer. The second argument to GRBloadenv() provides the name of the Gurobi log file. If the argument is an empty string or NULL, no log file will be written.

Note that environment creation may fail, so you should check the return value of the call.