gh-138850: Add --disable-epoll to configure (GH-145768)

* gh-138850: Add --disable-epoll to configure


Co-authored-by: Petr Viktorin <encukou@gmail.com>

Author: mtelka

Doc/library/select.rst

@@ -62,7 +62,7 @@ The module defines the following:
 
    *sizehint* informs epoll about the expected number of events to be
    registered.  It must be positive, or ``-1`` to use the default. It is only
-   used on older systems where :c:func:`!epoll_create1` is not available;
+   used on older systems where :manpage:`epoll_create1(2)` is not available;
    otherwise it has no effect (though its value is still checked).
 
    *flags* is deprecated and completely ignored.  However, when supplied, its
@@ -89,6 +89,11 @@ The module defines the following:
       The *flags* parameter.  ``select.EPOLL_CLOEXEC`` is used by default now.
       Use :func:`os.set_inheritable` to make the file descriptor inheritable.
 
+   .. versionchanged:: next
+
+      When CPython is built, this function may be disabled using
+      :option:`--disable-epoll`.
+
 
 .. function:: poll()
 

Doc/using/configure.rst

@@ -463,6 +463,17 @@ General Options
 
    ``pkg-config`` options.
 
+.. option:: --disable-epoll
+
+   Build without ``epoll``, meaning that :py:func:`select.epoll` will not be
+   present even if the system provides an
+   :manpage:`epoll_create <epoll_create(2)>` function.
+   This may be used on systems where :manpage:`!epoll_create` or
+   :manpage:`epoll_create1 <epoll_create1(2)>` is available
+   but incompatible with Linux semantics.
+
+   .. versionadded:: next
+
 
 C compiler options
 ------------------

Misc/NEWS.d/next/Build/2026-03-10-16-58-55.gh-issue-138850.CkqTw6.rst

@@ -0,0 +1 @@
+Add :option:`--disable-epoll` to ``configure``

configure

@@ -5389,8 +5389,20 @@ PY_CHECK_FUNC([symlink], [@%:@include <unistd.h>])
 PY_CHECK_FUNC([fchdir], [@%:@include <unistd.h>])
 PY_CHECK_FUNC([fsync], [@%:@include <unistd.h>])
 PY_CHECK_FUNC([fdatasync], [@%:@include <unistd.h>])
-PY_CHECK_FUNC([epoll_create], [@%:@include <sys/epoll.h>], [HAVE_EPOLL])
-PY_CHECK_FUNC([epoll_create1], [@%:@include <sys/epoll.h>])
+
+AC_MSG_CHECKING([for --disable-epoll])
+AC_ARG_ENABLE([epoll],
+  [AS_HELP_STRING([--disable-epoll], [disable epoll (default is yes if supported)])],
+  [AS_VAR_IF([enable_epoll], [no], [disable_epoll=yes], [disable_epoll=no])],
+  [disable_epoll=no]
+)
+AC_MSG_RESULT([$disable_epoll])
+if test "$disable_epoll" = "no"
+then
+  PY_CHECK_FUNC([epoll_create], [@%:@include <sys/epoll.h>], [HAVE_EPOLL])
+  PY_CHECK_FUNC([epoll_create1], [@%:@include <sys/epoll.h>])
+fi
+
 PY_CHECK_FUNC([kqueue],[
 #include <sys/types.h>
 #include <sys/event.h>