Generic vector implementation in C using preprocessor macros.

vector.h

#ifndef VECTOR_H
#define VECTOR_H

#include <stdint.h>
#include <stddef.h>
#include <malloc.h>

#define VECTOR(_type)                   VECTOR_##_type##_t
#define VECTOR_INIT(_type, _vec)        VECTOR_##_type##init(_vec)
#define VECTOR_FREE(_type, _vec)        VECTOR_##_type##free(_vec)
#define VECTOR_PUSH(_type, _vec, _item) VECTOR_##_type##push(_vec, _item)
#define VECTOR_POP(_type, _vec)         VECTOR_##_type##pop(_vec)

#define VECTOR_STUB(_type)                                      \
    typedef struct {                                            \
        _type *items;                                           \
        size_t count;                                           \
        size_t size;                                            \
    } VECTOR(_type);                                            \
                                                                \
    void                                                        \
    VECTOR_##_type##init(VECTOR(_type) * vec) {                 \
        vec->items = NULL;                                      \
        vec->count = 0;                                         \
        vec->size = 0;                                          \
    }                                                           \
                                                                \
    void                                                        \
    VECTOR_##_type##free(VECTOR(_type) * vec) {                 \
        free(vec->items);                                       \
        vec->count = 0;                                         \
        vec->size = 0;                                          \
    }                                                           \
                                                                \
    void                                                        \
    VECTOR_##_type##push(VECTOR(_type) * vec, _type item) {     \
        if (vec->size < vec->count + 1) {                       \
            vec->size = (vec->size < 8 ? 8 : vec->size * 2);    \
            vec->items = realloc(                               \
                vec->items, vec->size * sizeof(_type)           \
            );                                                  \
        }                                                       \
        vec->items[vec->count++] = item;                        \
    }                                                           \
                                                                \
    _type                                                       \
    VECTOR_##_type##pop(VECTOR(_type) * vec) {                  \
        /*XXX CHECK COUNT TO PREVENT BUFFER UNDERFLOW*/         \
        return vec->items[vec->count--];                        \
    }

#endif /* VECTOR_H */

vector_example.c

#include <vector.h>

// DECLARE VECTOR
VECTOR_STUB(int)

int main() {
    VECTOR(int) vec;
    VECTOR_INIT(int, &vec);

    for (int i = 200; i > 0; i--)
        VECTOR_PUSH(int, &vec, i);

    for (int i = 0; i < 100; i++) {
        int x = VECTOR_POP(int, &vec);
        printf("%d ==> %d\n", i, x);
    }

    VECTOR_FREE(int, &vec);
    return 0;
}