/in/vector.c: In function 'construct':
/in/vector.c:11:5: error: 'v' undeclared (first use in this function)
     v->data = NULL;
     ^
/in/vector.c:11:5: note: each undeclared identifier is reported only once for each function it appears in
/in/vector.c: In function 'destruct':
/in/vector.c:18:11: error: 'vector {aka struct vector_t}' has no member named 'data'
     free(v->data);
           ^~
/in/vector.c: In function 'extend':
/in/vector.c:21:21: error: unused parameter 'v' [-Werror=unused-parameter]
 void extend(vector *v)
                     ^
/in/vector.c: In function 'contract':
/in/vector.c:25:23: error: unused parameter 'v' [-Werror=unused-parameter]
 void contract(vector *v)
                       ^
/in/vector.c: In function 'push_back':
/in/vector.c:31:9: error: 'index' undeclared (first use in this function)
     if (index >= v->limit)
         ^~~~~
/in/vector.c:33:16: error: 'return' with a value, in function returning void [-Werror]
         return NULL;
                ^~~~
/in/vector.c:29:6: note: declared here
 void push_back(vector *v, int element)
      ^~~~~~~~~
/in/vector.c:35:13: error: 'vector {aka struct vector_t}' has no member named 'data'
     return v->data[index];
             ^~
/in/vector.c:35:12: error: 'return' with a value, in function returning void [-Werror]
     return v->data[index];
            ^
/in/vector.c:29:6: note: declared here
 void push_back(vector *v, int element)
      ^~~~~~~~~
/in/vector.c:29:31: error: unused parameter 'element' [-Werror=unused-parameter]
 void push_back(vector *v, int element)
                               ^~~~~~~
/in/vector.c: In function 'pop_back':
/in/vector.c:41:9: error: 'index' undeclared (first use in this function)
     if (index >= v->limit)
         ^~~~~
/in/vector.c:45:38: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
     for (int i = index, j = index; i < v->limit; i++)
                                      ^
/in/vector.c:47:10: error: 'vector {aka struct vector_t}' has no member named 'data'
         v->data[j] = v->data[i];
          ^~
/in/vector.c:47:23: error: 'vector {aka struct vector_t}' has no member named 'data'
         v->data[j] = v->data[i];
                       ^~
/in/vector.c: In function 'get':
/in/vector.c:59:16: error: return makes integer from pointer without a cast [-Werror=int-conversion]
         return NULL;
                ^~~~
/in/vector.c:61:13: error: 'vector {aka struct vector_t}' has no member named 'data'
     return v->data[index];
             ^~
/in/vector.c: In function 'change':
/in/vector.c:65:21: error: unused parameter 'v' [-Werror=unused-parameter]
 void change(vector *v, unsigned int index, int element)
                     ^
/in/vector.c:65:37: error: unused parameter 'index' [-Werror=unused-parameter]
 void change(vector *v, unsigned int index, int element)
                                     ^~~~~
/in/vector.c:65:48: error: unused parameter 'element' [-Werror=unused-parameter]
 void change(vector *v, unsigned int index, int element)
                                                ^~~~~~~
/in/vector.c: In function 'print':
/in/vector.c:70:20: error: unused parameter 'v' [-Werror=unused-parameter]
 void print(vector *v)
                    ^
/in/vector.c: In function 'construct':
/in/vector.c:15:1: error: control reaches end of non-void function [-Werror=return-type]
 }
 ^
/in/vector.c: In function 'get':
/in/vector.c:64:1: error: control reaches end of non-void function [-Werror=return-type]
 }
 ^
cc1: all warnings being treated as errors