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[英]Is read() on a nonblocking socket “greedy” on platforms other than Linux (OSX, FreeBSD)?
[英]Socket on linux work but not on osx
我正在为一个问题而苦苦挣扎,我的Linux套接字接口工作正常,但是在osx上,我没有使用gdb接收/发送任何数据,我发现select不会设置fd_set,因此我的代码永远不会读套接字:这可能是导致选择的代码:
static inline int max_fd_plusone(t_list *fds)
{
int max;
t_list *tmp;
t_selfd *fd;
max = -1;
tmp = fds;
while (tmp)
{
fd = (t_selfd*)tmp->data;
max = fd->fd > max ? fd->fd : max;
tmp = tmp->next;
}
return (max + 1);
}
static inline void set_fdset(t_list *fds, fd_set *setr, fd_set *setw)
{
t_list *tmp;
t_selfd *fd;
FD_ZERO(setr);
FD_ZERO(setw);
tmp = fds;
while (tmp)
{
fd = (t_selfd*)tmp->data;
if ((fd->checktype & FDREAD) == FDREAD)
FD_SET(fd->fd, setr);
if ((fd->checktype & FDWRITE) == FDWRITE)
FD_SET(fd->fd, setw);
tmp = tmp->next;
}
}
t_selfd *create_fd(int fd, void *data, int (*call)())
{
t_selfd *res;
if ((res = malloc(1 * sizeof(t_selfd))) == NULL)
return (NULL);
res->fd = fd;
res->etype = 0;
res->checktype = FDREAD;
res->data = data;
res->callback = call;
res->to_close = 0;
res->rbuff = create_ring_buffer(BUFSIZ * 2);
res->wbuff = create_ring_buffer(BUFSIZ * 2);
if (!res->rbuff || !res->wbuff)
{
destroy_ring_buffer(res->rbuff);
destroy_ring_buffer(res->wbuff);
free(res);
return (NULL);
}
return (res);
}
void do_select(t_list *fds, struct timeval *tv, void *global_arg)
{
fd_set setr;
fd_set setw;
t_list *tmp;
t_list *nexttmp;
t_selfd *fd;
nexttmp = NULL;
set_fdset(fds, &setr, &setw);
if ((select(max_fd_plusone(fds), &setr, &setw, NULL, tv) == -1))
return ;
tmp = fds;
nexttmp = tmp->next;
while (tmp)
{
fd = (t_selfd*)tmp->data;
fd->etype = (FD_ISSET(fd->fd, &setr)) * FDREAD
+ (FD_ISSET(fd->fd, &setw)) * FDWRITE;
fd->checktype = 0;
fd->callback(fd, global_arg);
tmp = nexttmp;
nexttmp = tmp ? tmp->next : NULL;
}
}
这看起来很可疑:
fd->etype = (FD_ISSET(fd->fd, &setr)) * FDREAD
+ (FD_ISSET(fd->fd, &setw)) * FDWRITE;
您假设FD_ISSET返回一个特定值(最有可能为1),而仅记录为返回非零或零。 操作系统之间肯定会有不同。
Linux在此返回归一化的布尔值(0或1),而MacOS则不。
注意:由于您似乎正在设计某些库,因此最好使用更现代的界面(例如poll
而不是select
。 如果执行的文件描述符过多,Select的性能会很差,并且可能会完全失败。
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