问使用calloc和freeing分配内存

EN

invalid operands to binary != (have ‘struct Devices_names’ and ‘void *’)

#include <stdio.h>
#include <stdlib.h>

static struct Devices_names {
#define MAX_NAME_LEN 80
    int id;
    char name[MAX_NAME_LEN];
} *devname;

static void g_create_device_names(size_t devices);
static void g_get_device_names();
static void destroy_devices();

int main(void)
{
#define DEVICES 5
    g_create_device_names(DEVICES);

    g_get_device_names();

    destroy_devices();

    return 0;
}

static void g_create_device_names(size_t devices)
{
    size_t i = 0;
    devname = calloc(devices, sizeof *devname);
    if(devname == NULL) {
        exit(0);
    }

    for(i = 0; i < devices; i++) {
        devname[i].id = i;
        sprintf(devname[i].name, "device: %d", i);
    }
}

static void g_get_device_names()
{
    size_t i = 0;

    for(i = 0; devname[i] != NULL; i++) { <-- ERROR HERE
        printf("Device id --- [ %d ]\n", devname[i].id);
        printf("Device name - [ %s ]\n", devname[i].name);
    }
}

static void destroy_devices()
{
    while(devname != NULL) {
        free(devname++);
    }
}