Re: avoiding unnecessary dependency on -lrt and -lpthread

[Paul Eggert]

Jim Meyering <address@hidden> writes:

> gethrxtime uses clock_gettime on Linux systems (and any other system
> without nanouptime), so such systems will get link errors for
> clock_gettime if it's in a separate library like -lrt.

Sorry, I didn't test with new-enough GNU/Linux systems.  I installed
this further patch to work around the problem.  This is "make check"
tested with Debian GNU/Linux 3.0 and 3.1-beta (x86), Solaris 8 64-bit
sparc (Forte 6 cc), Solaris 9 32-bit sparc (Forte 7 c89), and OpenBSD
3.4 x86.

2005-02-21  Paul Eggert  <address@hidden>

        * m4/xnanosleep.m4: New file.
        * lib/Makefile.am (libfetish_a_SOURCES): Remove xnanosleep.c,
        xnanosleep.h; now done by ../m4/xnanosleep.m4 automatically.
        * m4/gethrxtime.m4 (gl_PREREQ_GETHRXTIME): Require gl_CLOCK_TIME,
        gl_USE_SYSTEM_EXTENSIONS.  Check whether CLOCK_MONOTONIC is
        defined, and set LIB_GETHRXTIME accordingly.  This is needed
        for newer GNU/Linux systems that have clock_gettime, so that they
        link in the appropriate library for it when needed.
        * m4/prereq.m4 (gl_PREREQ): Require gl_XNANOSLEEP.
        * src/Makefile.am (dd_LDADD, shred_LDADD): Add $(LIB_GETHRXTIME).
        (nanosec_libs): Add $(LIB_XNANOSLEEP).  Needed for newer GNU/Linux
        hosts with clock_gettime.

--- /dev/null   2003-03-18 13:55:57 -0800
+++ m4/xnanosleep.m4    2005-02-21 22:52:42 -0800
@@ -0,0 +1,35 @@
+# xnanosleep.m4 serial 1
+dnl Copyright (C) 2005 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 Written by Paul Eggert.
+
+AC_DEFUN([gl_XNANOSLEEP],
+[
+  AC_LIBSOURCES([xnanosleep.c, xnanosleep.h])
+  AC_LIBOBJ([xnanosleep])
+
+  dnl Prerequisites of lib/xnanosleep.c.
+  AC_REQUIRE([gl_PREREQ_GETHRXTIME])
+
+  LIB_XNANOSLEEP=
+  case $LIB_GETHRXTIME in
+  ?*)
+    AC_CACHE_CHECK([whether __linux__ is defined],
+      gl_cv_have___linux__,
+      [AC_EGREP_CPP([have___linux__],
+       [
+#        ifdef __linux__
+         have___linux__
+#        endif
+       ],
+       gl_cv_have___linux__=yes,
+       gl_cv_have___linux__=no)])
+    if test $gl_cv_have___linux__ = yes; then
+      LIB_XNANOSLEEP=$LIB_GETHRXTIME
+    fi;;
+  esac
+  AC_SUBST([LIB_XNANOSLEEP])
+])
Index: lib/Makefile.am
===================================================================
RCS file: /fetish/cu/lib/Makefile.am,v
retrieving revision 1.213
diff -p -u -r1.213 Makefile.am
--- lib/Makefile.am     20 Feb 2005 12:25:43 -0000      1.213
+++ lib/Makefile.am     22 Feb 2005 06:58:35 -0000
@@ -56,7 +56,6 @@ libfetish_a_SOURCES = \
   xgetcwd.c xgetcwd.h \
   xgethostname.c xgethostname.h \
   xmemcoll.c xmemcoll.h \
-  xnanosleep.c xnanosleep.h \
   xreadlink.c xreadlink.h \
   xstrndup.c xstrndup.h \
   xstrtod.c xstrtod.h \
Index: m4/gethrxtime.m4
===================================================================
RCS file: /fetish/cu/m4/gethrxtime.m4,v
retrieving revision 1.1
diff -p -u -r1.1 gethrxtime.m4
--- m4/gethrxtime.m4    21 Feb 2005 08:06:25 -0000      1.1
+++ m4/gethrxtime.m4    22 Feb 2005 06:58:35 -0000
@@ -1,9 +1,11 @@
-# gethrxtime.m4 serial 1
+# gethrxtime.m4 serial 2
 dnl Copyright (C) 2005 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 Written by Paul Eggert.
+
 AC_DEFUN([gl_GETHRXTIME],
 [
   AC_LIBSOURCES([gethrxtime.c, gethrxtime.h, xtime.h])
@@ -48,10 +50,27 @@ AC_DEFUN([gl_XTIME],
 # Prerequisites of lib/gethrxtime.c.
 AC_DEFUN([gl_PREREQ_GETHRXTIME],
 [
-  dnl Do not AC_REQUIRE([gl_CLOCK_TIME]), since that would unnecessarily
-  dnl require -lrt on Solaris.  Invocations of clock_gettime should be
-  dnl safe in gethrxtime.c since Solaris has native gethrtime.
   AC_REQUIRE([AC_HEADER_TIME])
+  AC_REQUIRE([gl_CLOCK_TIME])
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
   AC_CHECK_FUNCS_ONCE(gettimeofday microuptime nanouptime)
-  :
+
+  if test $ac_cv_func_nanouptime != yes; then
+    LIB_GETHRXTIME=
+    AC_CACHE_CHECK([whether CLOCK_MONOTONIC is defined],
+      gl_cv_have_CLOCK_MONOTONIC,
+      [AC_EGREP_CPP([have_CLOCK_MONOTONIC],
+       [
+#        include <time.h>
+#        ifdef CLOCK_MONOTONIC
+         have_CLOCK_MONOTONIC
+#        endif
+       ],
+       gl_cv_have_CLOCK_MONOTONIC=yes,
+       gl_cv_have_CLOCK_MONOTONIC=no)])
+    if test $gl_cv_have_CLOCK_MONOTONIC = yes; then
+      LIB_GETHRXTIME=$LIB_CLOCK_GETTIME
+    fi
+    AC_SUBST([LIB_GETHRXTIME])
+  fi
 ])
Index: m4/prereq.m4
===================================================================
RCS file: /fetish/cu/m4/prereq.m4,v
retrieving revision 1.101
diff -p -u -r1.101 prereq.m4
--- m4/prereq.m4        21 Feb 2005 08:12:37 -0000      1.101
+++ m4/prereq.m4        22 Feb 2005 06:58:35 -0000
@@ -119,6 +119,7 @@ AC_DEFUN([gl_PREREQ],
   AC_REQUIRE([gl_UTIMENS])
   AC_REQUIRE([gl_XALLOC])
   AC_REQUIRE([gl_XGETCWD])
+  AC_REQUIRE([gl_XNANOSLEEP])
   AC_REQUIRE([gl_XREADLINK])
   AC_REQUIRE([gl_XSTRTOD])
   AC_REQUIRE([gl_XSTRTOL])
Index: src/Makefile.am
===================================================================
RCS file: /fetish/cu/src/Makefile.am,v
retrieving revision 1.50
diff -p -u -r1.50 Makefile.am
--- src/Makefile.am     21 Feb 2005 08:13:12 -0000      1.50
+++ src/Makefile.am     22 Feb 2005 06:58:36 -0000
@@ -43,10 +43,10 @@ test_LDADD = $(LDADD) $(LIB_EACCESS)
 __LDADD = $(LDADD) $(LIB_EACCESS)
 
 # for clock_gettime and fdatasync
-dd_LDADD = $(LDADD) $(LIB_FDATASYNC)
+dd_LDADD = $(LDADD) $(LIB_GETHRXTIME) $(LIB_FDATASYNC)
 dir_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME)
 ls_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME)
-shred_LDADD = $(LDADD) $(LIB_FDATASYNC)
+shred_LDADD = $(LDADD) $(LIB_GETHRXTIME) $(LIB_FDATASYNC)
 vdir_LDADD = $(LDADD) $(LIB_CLOCK_GETTIME)
 
 ## If necessary, add -lm to resolve use of pow in lib/strtod.c.
@@ -69,7 +69,7 @@ seq_LDADD = $(LDADD) $(SEQ_LIBM)
 # If necessary, add -lm to resolve the `pow' reference in lib/strtod.c
 # or for the fesetround reference in programs using nanosec.c.
 nanosec_libs = \
-  $(LDADD) $(FESETROUND_LIBM) $(POW_LIB) $(LIB_NANOSLEEP)
+  $(LDADD) $(FESETROUND_LIBM) $(POW_LIB) $(LIB_XNANOSLEEP) $(LIB_NANOSLEEP)
 
 sleep_LDADD = $(nanosec_libs)
 tail_LDADD = $(nanosec_libs)