FD_SETSIZE并选择增加限制 [英] Increasing limit of FD_SETSIZE and select

问题描述

我想提高FD_SETSIZE宏值我的系统。
有什么办法来增加FD_SETSIZE所以选择不会失败

I want to increase FD_SETSIZE macro value for my system. Is there any way to increase FD_SETSIZE so select will not fail

推荐答案

每标准，没有办法增加 FD_SETSIZE 。某些程序和库（libevent的想到）尝试为 FD_SET 对象分配额外的空间，通过较大的值比 FD_SETSIZE 到 FD _ * 宏，但是这是一个非常糟糕的主意，因为强大的实现可能的参数执行边界检查和中止如果它是超出范围。

Per the standards, there is no way to increase FD_SETSIZE. Some programs and libraries (libevent comes to mind) try to work around this by allocating additional space for the fd_set object and passing values larger than FD_SETSIZE to the FD_* macros, but this is a very bad idea since robust implementations may perform bounds-checking on the argument and abort if it's out of range.

我有一个替代的解决方案，应始终正常工作（即使它不是由标准的要求）。相反，一个 FD_SET 的对象，分配他们的大到足以容纳最大FD你需要，那么使用数组 FD_SET（FD％FD_SETSIZE ，＆安培; fds_array [FD / FD_SETSIZE]）等访问设置

I have an alternate solution that should always work (even though it's not required to by the standards). Instead of a single fd_set object, allocate an array of them large enough to hold the max fd you'll need, then use FD_SET(fd%FD_SETSIZE, &fds_array[fd/FD_SETSIZE]) etc. to access the set.

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