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From: Ken Brown <>
Subject: [newlib-cygwin] Cygwin: getdtablesize: always return OPEN_MAX_MAX
Date: Mon,  1 Feb 2021 14:58:54 +0000 (GMT)	[thread overview]
Message-ID: <> (raw);h=3d256e22e22d435d13cfecf39c15338cfbd6f587

commit 3d256e22e22d435d13cfecf39c15338cfbd6f587
Author: Ken Brown <>
Date:   Wed Jan 27 20:06:22 2021 -0500

    Cygwin: getdtablesize: always return OPEN_MAX_MAX
    According to the Linux man page for getdtablesize(3), the latter is
    supposed to return "the maximum number of files a process can have
    open, one more than the largest possible value for a file descriptor."
    The constant OPEN_MAX_MAX is the only limit enforced by Cygwin, so we
    now return that.
    Previously getdtablesize returned the current size of cygheap->fdtab,
    Cygwin's internal file descriptor table.  But this is a dynamically
    growing table, and its current size does not reflect an actual limit
    on the number of open files.
    With this change, gnulib now reports that getdtablesize and
    fcntl(F_DUPFD) work on Cygwin.  Packages like GNU tar that use the
    corresponding gnulib modules will no longer use gnulib replacements on

 winsup/cygwin/ | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/winsup/cygwin/ b/winsup/cygwin/
index 82ddad46d..d293ff2c0 100644
--- a/winsup/cygwin/
+++ b/winsup/cygwin/
@@ -2887,7 +2887,7 @@ setdtablesize (int size)
 extern "C" int
 getdtablesize ()
-  return cygheap->fdtab.size;
+  return OPEN_MAX_MAX;
 extern "C" int

                 reply	other threads:[~2021-02-01 14:58 UTC|newest]

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