# FP_COMPUTE_INT(EXPRESSION, VARIABLE, INCLUDES, IF-FAILS)
# --------------------------------------------------------
# Assign VARIABLE the value of the compile-time EXPRESSION using INCLUDES for
# compilation. Execute IF-FAILS when unable to determine the value. Works for
# cross-compilation, too.
#
# Implementation note: We are lazy and use an internal autoconf macro, but it
# is supported in autoconf versions 2.50 up to the actual 2.57, so there is
# little risk.
AC_DEFUN([FP_COMPUTE_INT],
[_AC_COMPUTE_INT([$1], [$2], [$3], [$4])[]dnl
])# FP_COMPUTE_INT


# FP_CHECK_CONST(EXPRESSION, [INCLUDES = DEFAULT-INCLUDES], [VALUE-IF-FAIL = -1])
# -------------------------------------------------------------------------------
# Defines CONST_EXPRESSION to the value of the compile-time EXPRESSION, using
# INCLUDES. If the value cannot be determined, use VALUE-IF-FAIL.
AC_DEFUN([FP_CHECK_CONST],
[AS_VAR_PUSHDEF([fp_Cache], [fp_cv_const_$1])[]dnl
AC_CACHE_CHECK([value of $1], fp_Cache,
[FP_COMPUTE_INT([$1], fp_check_const_result, [AC_INCLUDES_DEFAULT([$2])],
                [fp_check_const_result=m4_default([$3], ['-1'])])
AS_VAR_SET(fp_Cache, [$fp_check_const_result])])[]dnl
AC_DEFINE_UNQUOTED(AS_TR_CPP([CONST_$1]), AS_VAR_GET(fp_Cache), [The value of $1.])[]dnl
AS_VAR_POPDEF([fp_Cache])[]dnl
])# FP_CHECK_CONST


# FP_CHECK_CONSTS_TEMPLATE(EXPRESSION...)
# ---------------------------------------
# autoheader helper for FP_CHECK_CONSTS
m4_define([FP_CHECK_CONSTS_TEMPLATE],
[AC_FOREACH([fp_Const], [$1],
  [AH_TEMPLATE(AS_TR_CPP(CONST_[]fp_Const),
               [The value of ]fp_Const[.])])[]dnl
])# FP_CHECK_CONSTS_TEMPLATE


# FP_CHECK_CONSTS(EXPRESSION..., [INCLUDES = DEFAULT-INCLUDES], [VALUE-IF-FAIL = -1])
# -----------------------------------------------------------------------------------
# List version of FP_CHECK_CONST
AC_DEFUN([FP_CHECK_CONSTS],
[FP_CHECK_CONSTS_TEMPLATE([$1])dnl
for fp_const_name in $1
do
FP_CHECK_CONST([$fp_const_name], [$2], [$3])
done
])# FP_CHECK_CONSTS