noreturn: New module.

* lib/noreturn.h: New file.
* modules/noreturn: New file.
* tests/test-noreturn.c: New file.
* modules/noreturn-tests: New file.
* tests/test-noreturn-c++.cc: New file.
* modules/noreturn-c++-tests: New file.

7 files changed, 297 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 43e6639592..00d9277aaa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2017-04-28  Bruno Haible  <bruno@clisp.org>
+
+	noreturn: New module.
+	* lib/noreturn.h: New file.
+	* modules/noreturn: New file.
+	* tests/test-noreturn.c: New file.
+	* modules/noreturn-tests: New file.
+	* tests/test-noreturn-c++.cc: New file.
+	* modules/noreturn-c++-tests: New file.
+
 2017-04-27  Bruno Haible  <bruno@clisp.org>
 
 	wctype-h: Fix compilation error with the original mingw.org mingw.
diff --git a/lib/noreturn.h b/lib/noreturn.h
new file mode 100644
index 0000000000..353a1e41b0
--- /dev/null
+++ b/lib/noreturn.h
@@ -0,0 +1,111 @@
+/* Macros for declaring functions as non-returning.
+
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert and Bruno Haible.  */
+
+#ifndef _NORETURN_H
+#define _NORETURN_H 1
+
+/* A "non-returning" function is a function which cannot return normally.
+   It can transfer control only through longjmp(), throw (in C++), or similar
+   mechanisms.
+
+   This file defines two macros _GL_NORETURN_FUNC and _GL_NORETURN_FUNCPTR,
+   that declare a function to be non-returning.
+   _GL_NORETURN_FUNC is for use in function declarations and function
+   definitions.
+   _GL_NORETURN_FUNCPTR is for use on function pointers.
+
+   Comparison of this file with <stdnoreturn.h>:
+   <stdnoreturn.h> defines a macro (or keyword) _Noreturn that declares
+   a function to be non-returning.  _Noreturn is only for use in function
+   declarations and function definitions.
+   Therefore, if the non-returning functions you have to declare are unlikely
+   to be accessed through function pointers, and if the efficiency with C++
+   compilers other than g++, clang, MSVC++ is not an issue to you, you can use
+   module 'stdnoreturn' instead of this one, and _Noreturn instead of
+   _GL_NORETURN_FUNC.
+ */
+
+/* Declares that a function is nonreturning.
+   Use in C only code:
+     _GL_NORETURN_FUNC extern void func (void);
+     extern _GL_NORETURN_FUNC void func (void);
+     extern void _GL_NORETURN_FUNC func (void);
+   Use in C++ only code for a function with C linkage:
+     extern "C" { _GL_NORETURN_FUNC void func (void); }
+   Use in C++ only code for a function with C++ linkage:
+     _GL_NORETURN_FUNC extern void func (void);
+   Use in C & C++ code for a function with C linkage:
+     #ifdef __cplusplus
+     extern "C" {
+     #endif
+     _GL_NORETURN_FUNC void func (void);
+     #ifdef __cplusplus
+     }
+     #endif
+   Use in C & C++ code for a function with current language linkage:
+     _GL_NORETURN_FUNC extern void func (void);
+ */
+#if (3 <= __GNUC__ || (__GNUC__ == 2 && 8 <= __GNUC_MINOR__)) \
+    || (0x5110 <= __SUNPRO_C)
+  /* For compatibility with _GL_NORETURN_FUNCPTR on clang, use
+     __attribute__((__noreturn__)), not _Noreturn.  */
+# define _GL_NORETURN_FUNC __attribute__ ((__noreturn__))
+#elif 1200 <= _MSC_VER
+  /* Use MSVC specific syntax.  */
+# define _GL_NORETURN_FUNC __declspec (noreturn)
+#elif defined __cplusplus
+  /* Use ISO C++11 syntax when the compiler supports it.  */
+# if (__cplusplus >= 201103 && !(__GNUC__ == 4 && __GNUC_MINOR__ == 7)) \
+     || (_MSC_VER >= 1900)
+#  define _GL_NORETURN_FUNC [[noreturn]]
+# else
+#  define _GL_NORETURN_FUNC /* empty */
+# endif
+#else
+  /* Use ISO C11 syntax when the compiler supports it.  */
+# if __STDC_VERSION__ >= 201112 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)
+#  define _GL_NORETURN_FUNC _Noreturn
+# else
+#  define _GL_NORETURN_FUNC /* empty */
+# endif
+#endif
+
+/* Declares that a function is nonreturning.
+   Use in types and declarations that involve function pointers:
+     _GL_NORETURN_FUNCPTR void (*funcptr) (void);
+ */
+#if (3 <= __GNUC__ || (__GNUC__ == 2 && 8 <= __GNUC_MINOR__)) \
+    || (0x5110 <= __SUNPRO_C)
+# define _GL_NORETURN_FUNCPTR __attribute__ ((__noreturn__))
+#else
+# define _GL_NORETURN_FUNCPTR /* empty */
+#endif
+
+/* Comments about the compiler dependent language features:
+   - '_Noreturn'    - standardized by ISO C11, available in C only (not in C++),
+                      and not applicable to pointers.
+   - '[[noreturn]]' - standardized by ISO C++11, available in C++ only,
+                      and not applicable to pointers.
+   - '__attribute__((__noreturn__))' - available in GCC and clang only,
+                                       both in C and C++.
+   - '__declspec(noreturn)' - available in MSVC only,
+                              both in C and C++, not applicable to pointers.
+ */
+
+#endif /* _NORETURN_H */
diff --git a/modules/noreturn b/modules/noreturn
new file mode 100644
index 0000000000..388ee0c325
--- /dev/null
+++ b/modules/noreturn
@@ -0,0 +1,20 @@
+Description:
+Macros for declaring functions as non-returning.
+
+Files:
+lib/noreturn.h
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+
+Include:
+<noreturn.h>
+
+License:
+LGPLv2+
+
+Maintainer:
+Bruno Haible
diff --git a/modules/noreturn-c++-tests b/modules/noreturn-c++-tests
new file mode 100644
index 0000000000..e8a346650b
--- /dev/null
+++ b/modules/noreturn-c++-tests
@@ -0,0 +1,17 @@
+Files:
+tests/test-noreturn-c++.cc
+
+Status:
+c++-test
+
+Depends-on:
+ansi-c++-opt
+
+configure.ac:
+
+Makefile.am:
+if ANSICXX
+TESTS += test-noreturn-c++
+check_PROGRAMS += test-noreturn-c++
+test_noreturn_c___SOURCES = test-noreturn-c++.cc
+endif
diff --git a/modules/noreturn-tests b/modules/noreturn-tests
new file mode 100644
index 0000000000..61ec22b557
--- /dev/null
+++ b/modules/noreturn-tests
@@ -0,0 +1,11 @@
+Files:
+tests/test-noreturn.c
+
+Depends-on:
+noreturn-c++-tests
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-noreturn
+check_PROGRAMS += test-noreturn
diff --git a/tests/test-noreturn-c++.cc b/tests/test-noreturn-c++.cc
new file mode 100644
index 0000000000..d576b66f1e
--- /dev/null
+++ b/tests/test-noreturn-c++.cc
@@ -0,0 +1,60 @@
+/* Test of macros for declaring functions as non-returning.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2017.  */
+
+#include <config.h>
+
+#include <noreturn.h>
+
+/* Test _GL_NORETURN_FUNC on function declarations.  */
+
+extern "C" { _GL_NORETURN_FUNC void func1_c (void); }
+_GL_NORETURN_FUNC extern void func1_cxx (void);
+
+/* Test _GL_NORETURN_FUNC on function definitions.  */
+
+_GL_NORETURN_FUNC void funcd_cxx (void)
+{
+  for (;;)
+    ;
+}
+
+/* Test _GL_NORETURN_FUNCPTR.  */
+
+_GL_NORETURN_FUNCPTR void (*func1_c_ptr) (void) = func1_c;
+_GL_NORETURN_FUNCPTR void (*func1_cxx_ptr) (void) = func1_cxx;
+_GL_NORETURN_FUNCPTR void (*funcd_cxx_ptr) (void) = funcd_cxx;
+
+/* These could also be defined in a separate compilation unit.  */
+
+void func1_c (void)
+{
+  for (;;)
+    ;
+}
+
+void func1_cxx (void)
+{
+  for (;;)
+    ;
+}
+
+
+int
+main ()
+{
+}
diff --git a/tests/test-noreturn.c b/tests/test-noreturn.c
new file mode 100644
index 0000000000..e7c162a069
--- /dev/null
+++ b/tests/test-noreturn.c
@@ -0,0 +1,68 @@
+/* Test of macros for declaring functions as non-returning.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2017.  */
+
+#include <config.h>
+
+#include <noreturn.h>
+
+/* Test _GL_NORETURN_FUNC on function declarations.  */
+
+_GL_NORETURN_FUNC extern void func1 (void);
+extern _GL_NORETURN_FUNC void func2 (void);
+extern void _GL_NORETURN_FUNC func3 (void);
+
+/* Test _GL_NORETURN_FUNC on function definitions.  */
+
+_GL_NORETURN_FUNC void funcd (void)
+{
+  for (;;)
+    ;
+}
+
+/* Test _GL_NORETURN_FUNCPTR.  */
+
+_GL_NORETURN_FUNCPTR void (*func1_ptr) (void) = func1;
+_GL_NORETURN_FUNCPTR void (*func2_ptr) (void) = func2;
+_GL_NORETURN_FUNCPTR void (*func3_ptr) (void) = func3;
+_GL_NORETURN_FUNCPTR void (*funcd_ptr) (void) = funcd;
+
+/* These could also be defined in a separate compilation unit.  */
+
+void func1 (void)
+{
+  for (;;)
+    ;
+}
+
+void func2 (void)
+{
+  for (;;)
+    ;
+}
+
+void func3 (void)
+{
+  for (;;)
+    ;
+}
+
+
+int
+main ()
+{
+}