为什么在Windows上编译cups库后执行以下代码my_get_dests(0, 0, &dests)一直都返回0,找不到打印机,请各路英雄指点迷津
```c
#include <stdio.h>
#include <cups/cups.h>
typedef struct {
int num_dests;
cups_dest_t *dests;
} my_user_data_t;
int my_dest_cb(my_user_data_t *user_data, unsigned flags, cups_dest_t *dest) {
if (flags & CUPS_DEST_FLAGS_REMOVED) {
user_data->num_dests = cupsRemoveDest(dest->name, dest->instance, user_data->num_dests, &(user_data->dests));
}
else {
user_data->num_dests = cupsCopyDest(dest, user_data->num_dests, &(user_data->dests));
}
return 1;
}
int my_get_dests(cups_ptype_t type, cups_ptype_t mask, cups_dest_t **dests) {
my_user_data_t user_data = { 0, NULL };
if (!cupsEnumDests(CUPS_DEST_FLAGS_NONE, 1000, NULL, type, mask, (cups_dest_cb_t)my_dest_cb, &user_data)) {
cupsFreeDests(user_data.num_dests, user_data.dests);
*dests = NULL;
return 0;
}
else {
*dests = user_data.dests;
return user_data.num_dests;
}
}
int main(int argc, const char * argv[]) {
cups_dest_t *dests = NULL;
int num_dests = my_get_dests(0, 0, &dests);
printf("Destination found: %d\n", num_dests);
return 0;
}
```