getprogname: Move declaration from "getprogname.h" to <stdlib.h>

getprogname: Move declaration from "getprogname.h" to <stdlib.h>

[Bruno Haible]

Why is the getprogname() function declared in "getprogname.h"?

All platforms that have this function — Mac OS X, FreeBSD, NetBSD,
OpenBSD >= 5.4, Solaris >= 11, Cygwin, Android API level >= 21 —
declare it in <stdlib.h>. It thus appears very unlikely that, if
glibc ever adds this function, they would choose to declare it
in a header file other than <stdlib.h>.

I can find no rationale in the mailing list archive from 2016.

So, it makes sense to move the declaration of this function to <stdlib.h>.
For a transition period, "getprogname.h" can continue to exist, but will
emit a deprecation warning.


2023-01-21  Bruno Haible  <bruno@clisp.org>

	getprogname: Move declaration from "getprogname.h" to <stdlib.h>.
	* lib/stdlib.in.h (getprogname): New declaration.
	* lib/getprogname.h: Add deprecation warning.
	(getprogname): Remove declaration.
	* lib/getprogname.c: Include <stdlib.h> instead of getprogname.h.
	* m4/stdlib_h.m4 (gl_STDLIB_H): Test whether getprogname is declared.
	(gl_STDLIB_H_REQUIRE_DEFAULTS): Initialize GNULIB_GETPROGNAME.
	(gl_STDLIB_H_DEFAULTS): Initialize HAVE_GETPROGNAME.
	* m4/getprogname.m4 (gl_PREREQ_GETPROGNAME): New macro, extracted from
	gl_FUNC_GETPROGNAME. Set HAVE_GETPROGNAME.
	(gl_FUNC_GETPROGNAME): Remove code that was moved to
	gl_PREREQ_GETPROGNAME.
	* modules/stdlib (Makefile.am): Substitute GNULIB_GETPROGNAME and
	HAVE_GETPROGNAME.
	* modules/getprogname (Depends-on): Add stdlib.
	(configure.ac): Define a module indicator. Invoke gl_PREREQ_GETPROGNAME.
	(Makefile.am): Don't compile getprogname.c if not needed.
	(Include): List <stdlib.h> instead of getprogname.h.
	* tests/test-getprogname.c: Include <stdlib.h> instead of getprogname.h.
	* NEWS: Mention the change.
	* lib/argmatch.c: Don't include getprogname.h.
	* lib/c-stack.c: Likewise.
	* lib/error.c: Likewise.
	* lib/git-merge-changelog.c: Likewise.

diff --git a/NEWS b/NEWS
index b54781a6f8..e8cc0c4ae7 100644
--- a/NEWS
+++ b/NEWS
@@ -74,6 +74,9 @@ User visible incompatible changes
 
 Date        Modules         Changes
 
+2023-01-21  getprogname     The include file is changed from "getprogname.h"
+                            to <stdlib.h>.
+
 2023-01-15  stdalign        This module is deprecated.  Use alignasof instead.
 
 2023-01-07  timer_time      Link with $(TIMER_TIME_LIB) instead of
diff --git a/lib/argmatch.c b/lib/argmatch.c
index 1e5b77bf32..9cddb37d69 100644
--- a/lib/argmatch.c
+++ b/lib/argmatch.c
@@ -32,7 +32,6 @@
 
 #include "error.h"
 #include "quotearg.h"
-#include "getprogname.h"
 
 #if USE_UNLOCKED_IO
 # include "unlocked-io.h"
diff --git a/lib/c-stack.c b/lib/c-stack.c
index 079d86846d..f0078d51ad 100644
--- a/lib/c-stack.c
+++ b/lib/c-stack.c
@@ -52,7 +52,6 @@
 #include <sigsegv.h>
 
 #include "exitfail.h"
-#include "getprogname.h"
 #include "idx.h"
 #include "ignore-value.h"
 
diff --git a/lib/error.c b/lib/error.c
index 6875f134ed..ef4372875f 100644
--- a/lib/error.c
+++ b/lib/error.c
@@ -42,8 +42,6 @@
 # define USE_UNLOCKED_IO 0
 # define _GL_ATTRIBUTE_FORMAT_PRINTF_STANDARD(a, b)
 # define _GL_ARG_NONNULL(a)
-#else
-# include "getprogname.h"
 #endif
 
 #if USE_UNLOCKED_IO
diff --git a/lib/getprogname.c b/lib/getprogname.c
index 32c96043b0..279d79f012 100644
--- a/lib/getprogname.c
+++ b/lib/getprogname.c
@@ -16,11 +16,10 @@
 
 #include <config.h>
 
-/* Specification.  */
-#include "getprogname.h"
+/* Specification.  Also get __argv declaration.  */
+#include <stdlib.h>
 
 #include <errno.h> /* get program_invocation_name declaration */
-#include <stdlib.h> /* get __argv declaration */
 
 #ifdef _AIX
 # include <unistd.h>
@@ -53,13 +52,12 @@
 
 #if defined __SCO_VERSION__ || defined __sysv5__
 # include <fcntl.h>
-# include <stdlib.h>
 # include <string.h>
 #endif
 
 #include "basename-lgpl.h"
 
-#ifndef HAVE_GETPROGNAME             /* not Mac OS X, FreeBSD, NetBSD, OpenBSD >= 5.4, Cygwin */
+#ifndef HAVE_GETPROGNAME  /* not Mac OS X, FreeBSD, NetBSD, OpenBSD >= 5.4, Solaris >= 11, Cygwin, Android API level >= 21 */
 char const *
 getprogname (void)
 {
diff --git a/lib/getprogname.h b/lib/getprogname.h
index 4b9126f9d7..13314f21e2 100644
--- a/lib/getprogname.h
+++ b/lib/getprogname.h
@@ -19,22 +19,8 @@
 
 #include <stdlib.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/* Return the base name of the executing program.
-   On native Windows this will usually end in ".exe" or ".EXE". */
-#ifndef HAVE_GETPROGNAME
-extern char const *getprogname (void)
-# ifdef HAVE_DECL_PROGRAM_INVOCATION_NAME
-  _GL_ATTRIBUTE_PURE
-# endif
-  ;
-#endif
-
-#ifdef __cplusplus
-}
+#if __GNUC__ || (__clang_major__ >= 4)
+# warning "The include file getprogname.h is deprecated. Use <stdlib.h> instead."
 #endif
 
 #endif
diff --git a/lib/git-merge-changelog.c b/lib/git-merge-changelog.c
index 5708dd5eac..67a932c5df 100644
--- a/lib/git-merge-changelog.c
+++ b/lib/git-merge-changelog.c
@@ -176,7 +176,6 @@
 #include "minmax.h"
 #include "c-strstr.h"
 #include "fwriteerror.h"
-#include "getprogname.h"
 
 #define ASSERT(expr) \
   do                                                                         \
diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index b79e5f7096..55f31feb42 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -430,6 +430,26 @@ _GL_WARN_ON_USE (getloadavg, "getloadavg is not portable - "
 # endif
 #endif
 
+#if @GNULIB_GETPROGNAME@
+/* Return the base name of the executing program.
+   On native Windows this will usually end in ".exe" or ".EXE". */
+# if !@HAVE_GETPROGNAME@
+#  ifdef HAVE_DECL_PROGRAM_INVOCATION_NAME
+_GL_FUNCDECL_SYS (getprogname, const char *, (void) _GL_ATTRIBUTE_PURE);
+#  else
+_GL_FUNCDECL_SYS (getprogname, const char *, (void));
+#  endif
+# endif
+_GL_CXXALIAS_SYS (getprogname, const char *, (void));
+_GL_CXXALIASWARN (getprogname);
+#elif defined GNULIB_POSIXCHECK
+# undef getprogname
+# if HAVE_RAW_DECL_GETPROGNAME
+_GL_WARN_ON_USE (getprogname, "getprogname is unportable - "
+                 "use gnulib module getprogname for portability");
+# endif
+#endif
+
 #if @GNULIB_GETSUBOPT@
 /* Assuming *OPTIONP is a comma separated list of elements of the form
    "token" or "token=value", getsubopt parses the first of these elements.
diff --git a/m4/getprogname.m4 b/m4/getprogname.m4
index 7c306c80a9..0a4b9c874a 100644
--- a/m4/getprogname.m4
+++ b/m4/getprogname.m4
@@ -5,12 +5,19 @@
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
-# serial 5
+# serial 6
 
 AC_DEFUN([gl_FUNC_GETPROGNAME],
 [
-  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   gl_CHECK_FUNCS_ANDROID([getprogname], [[#include <stdlib.h>]])
+  if test $ac_cv_func_getprogname = no; then
+    HAVE_GETPROGNAME=0
+  fi
+])
+
+AC_DEFUN([gl_PREREQ_GETPROGNAME],
+[
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   AC_CHECK_FUNCS_ONCE([getexecname])
   ac_found=0
   AC_CHECK_DECLS([program_invocation_name], [ac_found=1], [],
diff --git a/m4/stdlib_h.m4 b/m4/stdlib_h.m4
index e96be22f58..f1f2d04047 100644
--- a/m4/stdlib_h.m4
+++ b/m4/stdlib_h.m4
@@ -1,4 +1,4 @@
-# stdlib_h.m4 serial 66
+# stdlib_h.m4 serial 67
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -23,7 +23,7 @@ AC_DEFUN_ONCE([gl_STDLIB_H],
 # include <random.h>
 #endif
     ]], [_Exit aligned_alloc atoll canonicalize_file_name free
-    getloadavg getsubopt grantpt
+    getloadavg getprogname getsubopt grantpt
     initstate initstate_r mbtowc mkdtemp mkostemp mkostemps mkstemp mkstemps
     posix_memalign posix_openpt ptsname ptsname_r qsort_r
     random random_r reallocarray realpath rpmatch secure_getenv setenv
@@ -73,6 +73,7 @@ AC_DEFUN([gl_STDLIB_H_REQUIRE_DEFAULTS],
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_CANONICALIZE_FILE_NAME])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FREE_POSIX])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETLOADAVG])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETPROGNAME])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GETSUBOPT])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_GRANTPT])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_MALLOC_GNU])
@@ -130,6 +131,7 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
   HAVE_DECL_FCVT=1;          AC_SUBST([HAVE_DECL_FCVT])
   HAVE_DECL_GCVT=1;          AC_SUBST([HAVE_DECL_GCVT])
   HAVE_DECL_GETLOADAVG=1;    AC_SUBST([HAVE_DECL_GETLOADAVG])
+  HAVE_GETPROGNAME=1;        AC_SUBST([HAVE_GETPROGNAME])
   HAVE_GETSUBOPT=1;          AC_SUBST([HAVE_GETSUBOPT])
   HAVE_GRANTPT=1;            AC_SUBST([HAVE_GRANTPT])
   HAVE_INITSTATE=1;          AC_SUBST([HAVE_INITSTATE])
diff --git a/modules/getprogname b/modules/getprogname
index 94e55186d5..dadbffbbd6 100644
--- a/modules/getprogname
+++ b/modules/getprogname
@@ -7,18 +7,26 @@ lib/getprogname.c
 m4/getprogname.m4
 
 Depends-on:
-basename-lgpl
-extensions
-open
+stdlib
+basename-lgpl   [test $HAVE_GETPROGNAME = 0]
+extensions      [test $HAVE_GETPROGNAME = 0]
+open            [test $HAVE_GETPROGNAME = 0]
 
 configure.ac:
 gl_FUNC_GETPROGNAME
+gl_CONDITIONAL([GL_COND_OBJ_GETPROGNAME], [test $HAVE_GETPROGNAME = 0])
+AM_COND_IF([GL_COND_OBJ_GETPROGNAME], [
+  gl_PREREQ_GETPROGNAME
+])
+gl_STDLIB_MODULE_INDICATOR([getprogname])
 
 Makefile.am:
-lib_SOURCES += getprogname.h getprogname.c
+if GL_COND_OBJ_GETPROGNAME
+lib_SOURCES += getprogname.c
+endif
 
 Include:
-"getprogname.h"
+<stdlib.h>
 
 License:
 LGPLv2+
diff --git a/modules/stdlib b/modules/stdlib
index 45d8f59331..1e6e18f53c 100644
--- a/modules/stdlib
+++ b/modules/stdlib
@@ -42,6 +42,7 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
 	      -e 's/@''GNULIB_CANONICALIZE_FILE_NAME''@/$(GNULIB_CANONICALIZE_FILE_NAME)/g' \
 	      -e 's/@''GNULIB_FREE_POSIX''@/$(GNULIB_FREE_POSIX)/g' \
 	      -e 's/@''GNULIB_GETLOADAVG''@/$(GNULIB_GETLOADAVG)/g' \
+	      -e 's/@''GNULIB_GETPROGNAME''@/$(GNULIB_GETPROGNAME)/g' \
 	      -e 's/@''GNULIB_GETSUBOPT''@/$(GNULIB_GETSUBOPT)/g' \
 	      -e 's/@''GNULIB_GRANTPT''@/$(GNULIB_GRANTPT)/g' \
 	      -e 's/@''GNULIB_MALLOC_GNU''@/$(GNULIB_MALLOC_GNU)/g' \
@@ -91,6 +92,7 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
 	      -e 's|@''HAVE_DECL_FCVT''@|$(HAVE_DECL_FCVT)|g' \
 	      -e 's|@''HAVE_DECL_GCVT''@|$(HAVE_DECL_GCVT)|g' \
 	      -e 's|@''HAVE_DECL_GETLOADAVG''@|$(HAVE_DECL_GETLOADAVG)|g' \
+	      -e 's|@''HAVE_GETPROGNAME''@|$(HAVE_GETPROGNAME)|g' \
 	      -e 's|@''HAVE_GETSUBOPT''@|$(HAVE_GETSUBOPT)|g' \
 	      -e 's|@''HAVE_GRANTPT''@|$(HAVE_GRANTPT)|g' \
 	      -e 's|@''HAVE_INITSTATE''@|$(HAVE_INITSTATE)|g' \
diff --git a/tests/test-getprogname.c b/tests/test-getprogname.c
index 0c1f1fcfa7..168c0cb91c 100644
--- a/tests/test-getprogname.c
+++ b/tests/test-getprogname.c
@@ -16,7 +16,8 @@
 
 #include <config.h>
 
-#include "getprogname.h"
+#include <stdlib.h>
+
 #include <string.h>
 #include <assert.h>
 

Re: getprogname: Move declaration from "getprogname.h" to <stdlib.h>

[Paul Eggert]

On 1/21/23 02:56, Bruno Haible wrote:
> For a transition period, "getprogname.h" can continue to exist, but will
> emit a deprecation warning.

Thanks for doing all that. I've removed "#include <getprogname.h>" from 
the programs I help maintain, and wouldn't object to a very short 
transition period since the current #warning is something I would treat 
like a diagnostic that getprogname.h is missing.

Re: getprogname: Move declaration from "getprogname.h" to <stdlib.h>

[Bruno Haible]

Paul Eggert wrote:
> I ... wouldn't object to a very short transition period

Short transition periods tend to cause unnecessary hassle to some users.
I therefore favour 1 year or 2 years as a transition period.

> since the current #warning is something I would treat 
> like a diagnostic that getprogname.h is missing.

I don't understand. Is the #warning that I added misleading? Then, by
all means, please provide a better message. (The compiler typically
reports the location of the warning; so, from the compiler's diagnostic
it should be clear that there still is a getprogname.h. No?)

Bruno

Re: getprogname: Move declaration from "getprogname.h" to <stdlib.h>

[Paul Eggert]

On 1/21/23 18:10, Bruno Haible wrote:
> I don't understand. Is the #warning that I added misleading?

No, all I meant was that if I see the warning I do the same thing that I 
do if I see the error from the missing #include, so there's not much 
point in having a transition period with the warning.

Things can be different the transition involves other ports or rarely 
used platforms. But this one involves all GNU/Linux platforms so I see 
the #warning right away.

Re: transition periods

[Bruno Haible]

Paul Eggert wrote:
> if I see the warning I do the same thing that I 
> do if I see the error from the missing #include, so there's not much 
> point in having a transition period with the warning.

I see a value for the transition period in three cases:

1)
> Things can be different the transition involves other ports or rarely 
> used platforms. But this one involves all GNU/Linux platforms so I see 
> the #warning right away.

The package might use the getprogname module only on specific platforms.
Thus, even though our change in Gnulib affected all platforms, in the
specific package it may not be visible immediately.

2) The maintainer may have a fixed release date scheduled. He then
wants to upgrade to a newer Gnulib, to fix some issue, but without
getting dragged into other changes.

3) The package may have a master branch and a release branch. The maintainer
uses "diff -r" to compare the code in the two branches. The two branches
may use different versions of Gnulib (via git submodules). Extra changes
between the two branches are unwelcome, even small ones. Thus the maintainer
will not want to remove '#include "getprogname.h"' statements as long as
his release branch is active; this can be several months.

These are just the scenarios that come out of my experience as maintainer /
release manager. I'm sure distro packagers have their habits, and some of
them will also favour longer transition periods.

Bruno