gh-83923: Added os.getdtablesize function to os module

Doc/library/os.rst

@@ -2229,6 +2229,13 @@ features:
 
    Return a string representing the current working directory.
 
+.. function:: getdtablesize()
+
+   Return the maximum number of files a process can have open.
+
+   .. versionadded:: 3.14
+
+   .. availability:: Unix.
 
 .. function:: getcwdb()
 

Lib/test/test_os.py

@@ -113,6 +113,12 @@ def test_getcwd(self):
         cwd = os.getcwd()
         self.assertIsInstance(cwd, str)
 
+    @unittest.skipUnless(hasattr(os, 'getdtablesize'), 'need os.getdtablesize()')
+    def test_getdtablesize(self):
+        size = os.getdtablesize()
+        self.assertIsInstance(size, int)
+        self.assertGreaterEqual(size, 0)
+
     def test_getcwd_long_path(self):
         # bpo-37412: On Linux, PATH_MAX is usually around 4096 bytes. On
         # Windows, MAX_PATH is defined as 260 characters, but Windows supports

Misc/NEWS.d/next/Library/2024-09-24-14-15-34.gh-issue-83923.YunOLX.rst

@@ -0,0 +1,2 @@
+Added :func:`os.getdtablesize` to :mod:`os` (supported only on unix-like
+systems)

Modules/posixmodule.c

@@ -4218,6 +4218,22 @@ os_getcwdb_impl(PyObject *module)
     return posix_getcwd(1);
 }
 
+#ifndef MS_WINDOWS
+/*[clinic input]
+os.getdtablesize
+
+Return the maximum number of files a process can have open.
+[clinic start generated code]*/
+
+static PyObject *
+os_getdtablesize_impl(PyObject *module)
+{
+    int size;
+
+    size = getdtablesize();
+    return PyLong_FromLong(size);
+}
+#endif  /* !MS_WINDOWS */
 
 #if ((!defined(HAVE_LINK)) && defined(MS_WINDOWS))
 #define HAVE_LINK 1
@@ -16843,6 +16859,7 @@ static PyMethodDef posix_methods[] = {
     OS_CTERMID_METHODDEF
     OS_GETCWD_METHODDEF
     OS_GETCWDB_METHODDEF
+    OS_GETDTABLESIZE_METHODDEF
     OS_LINK_METHODDEF
     OS_LISTDIR_METHODDEF
     OS_LISTDRIVES_METHODDEF

configure.ac

@@ -5149,7 +5149,7 @@ AC_CHECK_FUNCS([ \
   fork fork1 fpathconf fstatat ftime ftruncate futimens futimes futimesat \
   gai_strerror getegid geteuid getgid getgrent getgrgid getgrgid_r \
   getgrnam_r getgrouplist gethostname getitimer getloadavg getlogin \
-  getpeername getpgid getpid getppid getpriority _getpty \
+  getpeername getpgid getpid getppid getpriority _getpty getdtablesize \
   getpwent getpwnam_r getpwuid getpwuid_r getresgid getresuid getrusage getsid getspent \
   getspnam getuid getwd grantpt if_nameindex initgroups kill killpg lchown linkat \
   lockf lstat lutimes madvise mbrtowc memrchr mkdirat mkfifo mkfifoat \