#ifndef CHARVEC_H#define CHARVEC_H#include <unistd.h>typedef struct charvec {    char *a;    unsigned int len;    unsigned int max;    void *((*alloc)(void*, size_t));    void (*free)(void*);} charvec_t;int charvec_fini(charvec_t *t);int charvec_need(charvec_t *t, unsigned int n);int charvec_more(charvec_t *t, unsigned int n);int charvec_append(charvec_t *t, char e);int charvec_fit(charvec_t *t);#define charvec_INIT(a,f)  {0, 0, 0, a, f}#endif /* CHARVEC_H */