I'm on OpenBSD 5.7 amd64, w/ all the latest stable patches. When I simply launch xfce (from ports), an xterm, and ~34 "xedit" windows, I get: "Maximum number of clients reachedError: Can't open display: :0.0". I think I also had the same problem earlier when running fvwm instead of xfce.
I've searched thru code (not yet exhaustively), searched the mailing lists, & the web with DuckDuckGo(DDG), and tried various things. Most DDG search results talk about buggy apps, or closing windows, but I don't think that's my problem as I don't have that many windows open. Three of the search results say this (though the info could be old, by several years or more): "By default, the X server has a limit of just 128. In order to increase this limit, you need to run at least Solaris 8 or an earlier release with the Xserver patch applies that fixes bug: 4185418 the X server should support more connections .Then change the Xservers configuration file and add the "-clients 1024" option to the X commandline." However, I've passed "-clients 1024" to the startx command with no effect, and I don't see that as a parameter in 'man X' or 'man Xservers'. Maybe that parameter needs to go in a config file somewhere, but I'm floundering at this point in the X config stuff. When I searched through the xenocara code, I found that the error comes from xserver/os/connection.c, where a constant "NOROOM" contains the error message, and interesting functions being called include AllocNewConnection, ErrorConnMax, and InitConnectionLimits which is where the variable "MaxClients" is being set. When I opened enough "xedit" windows to reproduce the error, just now, then closed one of them and ran "xwininfo -root -children|wc" I got a result of 213. Then I killed those 17 xedit windows (I have other things open now also) and "xwininfo -root -children|wc" said 94. That's about as far as I've got, since I'm new enough with this to be unsure whether I'm going in a good direction, diagnostically; my ignorance might be causing this to take longer than needed, and I'm hoping not to have to run X in gdb.... Any ideas appreciated. Thanks!! Luke