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From: Steven Bardwell <SBardwell AT lbmsys DOT com>
To: "cygwin AT cygwin DOT com" <cygwin AT cygwin DOT com>
Subject: FD_SETSIZE and sizeof(fd_set)
Date: Wed, 22 Jun 2016 22:19:20 +0000
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I am running into a problem with the fd_set structure that someone may know the answer to. 

I would like to be able to call select() on more than 64 open files, so I have done the following:

1)   the include section of the program has the code:

#undef FD_SETSIZE
#define FD_SETSIZE 256
#include <sys/types.h>

2) however, when I query the size of the fd_set structure, sizeof(fd_set) return 8 bytes. 

This obviously breaks things when the fd is greater than 64.

Is there a proper way of supporting more than 64 open files in a process? I am guessing there is an easy answer -- if not, I can supply sample code that shows the problem.

Steve Bardwell


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