New upstream version 1.9

[debian/gzip] / m4 / getdtablesize.m4

diff --git a/m4/getdtablesize.m4 b/m4/getdtablesize.m4
index 1bf4db043e6e241c538e78f7d5e68da80c209316..4cc1a8ff21e7f22952b8725f446a03e99ae2c494 100644 (file)
--- a/m4/getdtablesize.m4
+++ b/m4/getdtablesize.m4
@@ -1,5 +1,5 @@
-# getdtablesize.m4 serial 6
-dnl Copyright (C) 2008-2016 Free Software Foundation, Inc.
+# getdtablesize.m4 serial 7
+dnl Copyright (C) 2008-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -12,29 +12,43 @@ AC_DEFUN([gl_FUNC_GETDTABLESIZE],
   AC_CHECK_DECLS_ONCE([getdtablesize])
   if test $ac_cv_func_getdtablesize = yes &&
      test $ac_cv_have_decl_getdtablesize = yes; then
-    # Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft limit
-    # up to an unchangeable hard limit; all other platforms correctly
-    # require setrlimit before getdtablesize() can report a larger value.
     AC_CACHE_CHECK([whether getdtablesize works],
       [gl_cv_func_getdtablesize_works],
-      [AC_RUN_IFELSE([
-        AC_LANG_PROGRAM([[#include <unistd.h>]],
-          [int size = getdtablesize();
-           if (dup2 (0, getdtablesize()) != -1)
-             return 1;
-           if (size != getdtablesize())
-             return 2;
-          ])],
-        [gl_cv_func_getdtablesize_works=yes],
-        [gl_cv_func_getdtablesize_works=no],
-        [case "$host_os" in
-          cygwin*) # on cygwin 1.5.25, getdtablesize() automatically grows
-            gl_cv_func_getdtablesize_works="guessing no" ;;
-          *) gl_cv_func_getdtablesize_works="guessing yes" ;;
-         esac])
+      [dnl There are two concepts: the "maximum possible file descriptor value + 1"
+       dnl and the "maximum number of open file descriptors in a process".
+       dnl Per SUSv2 and POSIX, getdtablesize() should return the first one.
+       dnl On most platforms, the first and the second concept are the same.
+       dnl On OpenVMS, however, they are different and getdtablesize() returns
+       dnl the second one; thus the test below fails. But we don't care
+       dnl because there's no good way to write a replacement getdtablesize().
+       case "$host_os" in
+         vms*) gl_cv_func_getdtablesize_works="no (limitation)" ;;
+         *)
+           dnl Cygwin 1.7.25 automatically increases the RLIMIT_NOFILE soft
+           dnl limit up to an unchangeable hard limit; all other platforms
+           dnl correctly require setrlimit before getdtablesize() can report
+           dnl a larger value.
+           AC_RUN_IFELSE([
+             AC_LANG_PROGRAM([[#include <unistd.h>]],
+               [int size = getdtablesize();
+                if (dup2 (0, getdtablesize()) != -1)
+                  return 1;
+                if (size != getdtablesize())
+                  return 2;
+               ])],
+             [gl_cv_func_getdtablesize_works=yes],
+             [gl_cv_func_getdtablesize_works=no],
+             [case "$host_os" in
+                cygwin*) # on cygwin 1.5.25, getdtablesize() automatically grows
+                  gl_cv_func_getdtablesize_works="guessing no" ;;
+                *) gl_cv_func_getdtablesize_works="guessing yes" ;;
+              esac
+             ])
+           ;;
+       esac
       ])
     case "$gl_cv_func_getdtablesize_works" in
-      *yes) ;;
+      *yes | "no (limitation)") ;;
       *) REPLACE_GETDTABLESIZE=1 ;;
     esac
   else