1 files changed, 100 insertions, 0 deletions

diff --git a/gl/m4/fclose.m4 b/gl/m4/fclose.m4
new file mode 100644
index 00000000..cfb92e28
--- /dev/null
+++ b/gl/m4/fclose.m4
@@ -0,0 +1,100 @@
+# fclose.m4
+# serial 12
+dnl Copyright (C) 2008-2025 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.
+dnl This file is offered as-is, without any warranty.
+
+AC_DEFUN_ONCE([gl_FUNC_FCLOSE],
+[
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  gl_FUNC_FFLUSH_STDIN
+  case "$gl_cv_func_fflush_stdin" in
+    *yes) ;;
+    *) REPLACE_FCLOSE=1 ;;
+  esac
+
+  AC_REQUIRE([gl_FUNC_CLOSE])
+  if test $REPLACE_CLOSE = 1; then
+    REPLACE_FCLOSE=1
+  fi
+
+  case "$host_os" in
+    openedition) REPLACE_FCLOSE=1 ;;
+  esac
+
+  if test $REPLACE_FCLOSE = 0; then
+    gl_FUNC_FCLOSE_STDIN
+    case "$gl_cv_func_fclose_stdin" in
+      *yes) ;;
+      *) REPLACE_FCLOSE=1 ;;
+    esac
+  fi
+])
+
+dnl Determine whether fclose works on input streams.
+dnl Sets gl_cv_func_fclose_stdin.
+
+AC_DEFUN([gl_FUNC_FCLOSE_STDIN],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CHECK_HEADERS_ONCE([unistd.h])
+  AC_CACHE_CHECK([whether fclose works on input streams],
+    [gl_cv_func_fclose_stdin],
+    [echo hello world > conftest.txt
+     AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <fcntl.h>
+            #include <stdio.h>
+            #if HAVE_UNISTD_H
+            # include <unistd.h>
+            #else /* on Windows with MSVC */
+            # include <io.h>
+            #endif
+           ]GL_MDA_DEFINES],
+          [[int fd;
+            int fd2;
+            FILE *fp;
+            fd = open ("conftest.txt", O_RDONLY);
+            if (fd < 0)
+              return 1;
+            if (lseek (fd, 1, SEEK_SET) != 1)
+              return 2;
+            fd2 = dup (fd);
+            if (fd2 < 0)
+              return 3;
+            fp = fdopen (fd2, "r");
+            if (fp == NULL)
+              return 4;
+            if (fgetc (fp) != 'e')
+              { fclose (fp); return 5; }
+            /* This fclose() call should reposition the underlying file
+               descriptor.  */
+            if (fclose (fp) != 0)
+              return 6;
+            if (lseek (fd2, 0, SEEK_CUR) != -1) /* should fail with EBADF */
+              return 7;
+            /* Verify the file position.  */
+            if (lseek (fd, 0, SEEK_CUR) != 2)
+              return 8;
+            return 0;
+          ]])],
+       [gl_cv_func_fclose_stdin=yes],
+       [gl_cv_func_fclose_stdin=no],
+       [case "$host_os" in
+                              # Guess no on glibc systems.
+          *-gnu* | gnu*)      gl_cv_func_fclose_stdin="guessing no" ;;
+                              # Guess yes on musl systems.
+          *-musl* | midipix*) gl_cv_func_fclose_stdin="guessing yes" ;;
+                              # Guess no on native Windows.
+          mingw* | windows*)  gl_cv_func_fclose_stdin="guessing no" ;;
+                              # If we don't know, obey --enable-cross-guesses.
+          *)                  gl_cv_func_fclose_stdin="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm conftest.txt
+    ])
+])