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-rw-r--r--ares/m4/cares-functions.m4106
1 files changed, 106 insertions, 0 deletions
diff --git a/ares/m4/cares-functions.m4 b/ares/m4/cares-functions.m4
index 70864ab7b..d98513573 100644
--- a/ares/m4/cares-functions.m4
+++ b/ares/m4/cares-functions.m4
@@ -43,6 +43,27 @@ cares_includes_string="\
])
+dnl CARES_INCLUDES_SYS_UIO
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when sys/uio.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_SYS_UIO], [
+cares_includes_sys_uio="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_UIO_H
+# include <sys/uio.h>
+#endif
+/* includes end */"
+ AC_CHECK_HEADERS(
+ sys/types.h sys/uio.h,
+ [], [], [$cares_includes_sys_uio])
+])
+
+
dnl CARES_CHECK_FUNC_STRCASECMP
dnl -------------------------------------------------
dnl Verify if strcasecmp is available, prototyped, and
@@ -636,3 +657,88 @@ AC_DEFUN([CARES_CHECK_FUNC_STRNICMP], [
ac_cv_func_strnicmp="no"
fi
])
+
+
+dnl CARES_CHECK_FUNC_WRITEV
+dnl -------------------------------------------------
+dnl Verify if writev is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_writev, then
+dnl HAVE_WRITEV will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_WRITEV], [
+ AC_REQUIRE([CARES_INCLUDES_SYS_UIO])dnl
+ #
+ tst_links_writev="unknown"
+ tst_proto_writev="unknown"
+ tst_compi_writev="unknown"
+ tst_allow_writev="unknown"
+ #
+ AC_MSG_CHECKING([if writev can be linked])
+ AC_LINK_IFELSE([
+ AC_LANG_FUNC_LINK_TRY([writev])
+ ],[
+ AC_MSG_RESULT([yes])
+ tst_links_writev="yes"
+ ],[
+ AC_MSG_RESULT([no])
+ tst_links_writev="no"
+ ])
+ #
+ if test "$tst_links_writev" = "yes"; then
+ AC_MSG_CHECKING([if writev is prototyped])
+ AC_EGREP_CPP([writev],[
+ $cares_includes_sys_uio
+ ],[
+ AC_MSG_RESULT([yes])
+ tst_proto_writev="yes"
+ ],[
+ AC_MSG_RESULT([no])
+ tst_proto_writev="no"
+ ])
+ fi
+ #
+ if test "$tst_proto_writev" = "yes"; then
+ AC_MSG_CHECKING([if writev is compilable])
+ AC_COMPILE_IFELSE([
+ AC_LANG_PROGRAM([[
+ $cares_includes_sys_uio
+ ]],[[
+ if(0 != writev(0, 0, 0))
+ return 1;
+ ]])
+ ],[
+ AC_MSG_RESULT([yes])
+ tst_compi_writev="yes"
+ ],[
+ AC_MSG_RESULT([no])
+ tst_compi_writev="no"
+ ])
+ fi
+ #
+ if test "$tst_compi_writev" = "yes"; then
+ AC_MSG_CHECKING([if writev usage allowed])
+ if test "x$cares_disallow_writev" != "xyes"; then
+ AC_MSG_RESULT([yes])
+ tst_allow_writev="yes"
+ else
+ AC_MSG_RESULT([no])
+ tst_allow_writev="no"
+ fi
+ fi
+ #
+ AC_MSG_CHECKING([if writev might be used])
+ if test "$tst_links_writev" = "yes" &&
+ test "$tst_proto_writev" = "yes" &&
+ test "$tst_compi_writev" = "yes" &&
+ test "$tst_allow_writev" = "yes"; then
+ AC_MSG_RESULT([yes])
+ AC_DEFINE_UNQUOTED(HAVE_WRITEV, 1,
+ [Define to 1 if you have the writev function.])
+ ac_cv_func_writev="yes"
+ else
+ AC_MSG_RESULT([no])
+ ac_cv_func_writev="no"
+ fi
+])