--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/chkspawn.c	Fri Oct 19 14:06:22 2007 +0200
@@ -0,0 +1,48 @@
+#include "substdio.h"
+#include "subfd.h"
+#include "fmt.h"
+#include "select.h"
+#include "exit.h"
+#include "auto_spawn.h"
+
+char num[FMT_ULONG];
+fd_set fds;
+
+void main()
+{
+  unsigned long hiddenlimit;
+  unsigned long maxnumd;
+ 
+  hiddenlimit = sizeof(fds) * 8;
+  maxnumd = (hiddenlimit - 5) / 2;
+ 
+  if (auto_spawn < 1) {
+    substdio_puts(subfderr,"Oops. You have set conf-spawn lower than 1.\n");
+    substdio_flush(subfderr);
+    _exit(1);
+  }
+
+  if (auto_spawn > 255) {
+    substdio_puts(subfderr,"Oops. You have set conf-spawn higher than 255.\n");
+    substdio_flush(subfderr);
+    _exit(1);
+  }
+
+  if (auto_spawn > maxnumd) {
+    substdio_puts(subfderr,"Oops. Your system's FD_SET() has a hidden limit of ");
+    substdio_put(subfderr,num,fmt_ulong(num,hiddenlimit));
+    substdio_puts(subfderr," descriptors.\n\
+This means that the qmail daemons could crash if you set the run-time\n\
+concurrency higher than ");
+    substdio_put(subfderr,num,fmt_ulong(num,maxnumd));
+    substdio_puts(subfderr,". So I'm going to insist that the concurrency\n\
+limit in conf-spawn be at most ");
+    substdio_put(subfderr,num,fmt_ulong(num,maxnumd));
+    substdio_puts(subfderr,". Right now it's ");
+    substdio_put(subfderr,num,fmt_ulong(num,(unsigned long) auto_spawn));
+    substdio_puts(subfderr,".\n");
+    substdio_flush(subfderr);
+    _exit(1);
+  }
+  _exit(0);
+}