c - 错误: dereferencing pointer to incomplete type when accessing struct

Question

我不确定为什么会发生这种情况。我正在做一项作业，但代码不知何故无法编译。

这是头文件

#include <stdint.h>

typedef struct
{
    uint8_t jump_code[3];   /* Ignore this */
    char oemname[8];        /* Might as well ignore this one too */
    uint8_t ssize[2];       /* Sector size in bytes */
    uint8_t csize;          /* Cluster size in sectors */
    uint8_t reserved[2];    /* Number of reserved sectors for boot sectors */
    uint8_t numfat;         /* Number of FATs */
    uint8_t numroot[2];     /* Number of Root directory entries */
    uint8_t sectors16[2];   /* number of sectors in the file system */
    uint8_t media[1];       /* Media descriptor type */
    uint8_t sectperfat16[2];/* Number of sectors per FAT */
    uint8_t sectpertrack[2];/* Number of sectors per track */
    uint8_t heads[2];       /* Number of heads */
    uint8_t prevsect[2];    /* Number of sectors before FS partition */
    uint8_t ignore[482];    /* Ignore these */
} boot_sect_t;

这是给出错误的部分:

struct boot_sect_t* boot = malloc(sizeof(boot_sect_t));
boot->ssize[0] = buffer[11]; //error here
boot->ssize[1] = buffer[12]; //error here

错误是:

error: dereferencing pointer to incomplete type when accessing struct

Answer 1

你需要改变

struct boot_sect_t* boot = malloc(sizeof(boot_sect_t));

至

boot_sect_t* boot = malloc(sizeof(boot_sect_t));

boot_sect_t 已经是 typedef。无需编写struct boot_sect_t。