c - ‘->’ 的无效类型参数(有 ‘fd_set’ )

Question

我知道这不是出现此错误的第一个线程，但我真的无法理解问题所在...我的代码如下:

/* File descriptor sets */
struct descs {
    fd_set read;
    fd_set write;
    fd_set except;
};

typedef struct descs descs_t;

/* Server representation */
struct server {
    int                 sock;                   /* Server sock descriptor */
    struct sockaddr_in  addr;                   /* Server address */
    socklen_t           addrlen;                /* Server address size */
    char                buffer[BUFFER_SIZE];    /* Message buffer */
    int                 len;                    /* Message buffer length */
};

typedef struct server server_t;

void build_fds(struct server *srv, struct descs *fd) {
    FD_ZERO(fd->read);
    FD_SET(STDIN_FILENO, fd->read);
    FD_SET(srv->sock, fd->read);

    FD_ZERO(fd->write);
    // there is smth to send, set up write_fd for server socket
    if (srv->len > 0) {
        FD_SET(srv->sock, fd->write);
    }

    FD_ZERO(fd->except);
    FD_SET(STDIN_FILENO, fd->except);
    FD_SET(srv->sock, fd->except);
}

我通过指针传递我的结构，所以我必须使用 -> 但它因错误而崩溃:

chatcl.c: In function ‘build_fds’:
chatcl.c:37: error: invalid type argument of ‘->’ (have ‘fd_set’)
chatcl.c:38: error: invalid type argument of ‘->’ (have ‘fd_set’)
chatcl.c:39: error: invalid type argument of ‘->’ (have ‘fd_set’)
chatcl.c:41: error: invalid type argument of ‘->’ (have ‘fd_set’)
chatcl.c:44: error: invalid type argument of ‘->’ (have ‘fd_set’)
chatcl.c:47: error: invalid type argument of ‘->’ (have ‘fd_set’)
chatcl.c:48: error: invalid type argument of ‘->’ (have ‘fd_set’)
chatcl.c:49: error: invalid type argument of ‘->’ (have ‘fd_set’)
make: *** [chatcl] Error 1

我的代码有什么问题？

Answer 1

您缺少 &，即您需要数据结构的地址，例如

#include <sys/select.h>

struct descs {
  fd_set a;
};

void func(struct descs *d) {
  FD_ZERO(&d->a);
}