avoid name clash with posix_close (closes #20594)

Misc/NEWS

@@ -44,6 +44,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #20594: Avoid name clash with the libc function posix_close.
+
 - Issue #19856: shutil.move() failed to move a directory to other directory
   on Windows if source name ends with os.altsep.
 

Modules/posixmodule.c

@@ -6581,8 +6581,12 @@ PyDoc_STRVAR(posix_close__doc__,
 "close(fd)\n\n\
 Close a file descriptor (for low level IO).");
 
+/*
+The underscore at end of function name avoids a name clash with the libc
+function posix_close.
+*/
 static PyObject *
-posix_close(PyObject *self, PyObject *args)
+posix_close_(PyObject *self, PyObject *args)
 {
     int fd, res;
     if (!PyArg_ParseTuple(args, "i:close", &fd))
@@ -8960,7 +8964,7 @@ static PyMethodDef posix_methods[] = {
     {"tcsetpgrp",       posix_tcsetpgrp, METH_VARARGS, posix_tcsetpgrp__doc__},
 #endif /* HAVE_TCSETPGRP */
     {"open",            posix_open, METH_VARARGS, posix_open__doc__},
-    {"close",           posix_close, METH_VARARGS, posix_close__doc__},
+    {"close",           posix_close_, METH_VARARGS, posix_close__doc__},
     {"closerange",      posix_closerange, METH_VARARGS, posix_closerange__doc__},
     {"dup",             posix_dup, METH_VARARGS, posix_dup__doc__},
     {"dup2",            posix_dup2, METH_VARARGS, posix_dup2__doc__},