# math_h.m4 serial 114 dnl Copyright (C) 2007-2012 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. AC_DEFUN([gl_MATH_H], [ AC_REQUIRE([gl_MATH_H_DEFAULTS]) gl_CHECK_NEXT_HEADERS([math.h]) AC_CACHE_CHECK([whether NAN macro works], [gl_cv_header_math_nan_works], [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include ]], [[/* Solaris 10 has a broken definition of NAN. Other platforms fail to provide NAN, or provide it only in C99 mode; this test only needs to fail when NAN is provided but wrong. */ float f = 1.0f; #ifdef NAN f = NAN; #endif return f == 0;]])], [gl_cv_header_math_nan_works=yes], [gl_cv_header_math_nan_works=no])]) if test $gl_cv_header_math_nan_works = no; then REPLACE_NAN=1 fi AC_CACHE_CHECK([whether HUGE_VAL works], [gl_cv_header_math_huge_val_works], [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include ]], [[/* Solaris 10 has a broken definition of HUGE_VAL. */ double d = HUGE_VAL; return d == 0;]])], [gl_cv_header_math_huge_val_works=yes], [gl_cv_header_math_huge_val_works=no])]) if test $gl_cv_header_math_huge_val_works = no; then REPLACE_HUGE_VAL=1 fi dnl Check for declarations of anything we want to poison if the dnl corresponding gnulib module is not in use. gl_WARN_ON_USE_PREPARE([[#include ]], [acosf acosl asinf asinl atanf atanl cbrt cbrtf cbrtl ceilf ceill copysign copysignf copysignl cosf cosl coshf expf expl exp2 exp2f exp2l expm1 expm1f expm1l fabsf fabsl floorf floorl fma fmaf fmal fmod fmodf fmodl frexpf frexpl hypotf hypotl ilogb ilogbf ilogbl ldexpf ldexpl log logf logl log10 log10f log10l log1p log1pf log1pl log2 log2f log2l logb logbf logbl modf modff modfl powf remainder remainderf remainderl rint rintf rintl round roundf roundl sinf sinl sinhf sqrtf sqrtl tanf tanl tanhf trunc truncf truncl]) ]) AC_DEFUN([gl_MATH_MODULE_INDICATOR], [ dnl Use AC_REQUIRE here, so that the default settings are expanded once only. AC_REQUIRE([gl_MATH_H_DEFAULTS]) gl_MODULE_INDICATOR_SET_VARIABLE([$1]) dnl Define it also as a C macro, for the benefit of the unit tests. gl_MODULE_INDICATOR_FOR_TESTS([$1]) ]) AC_DEFUN([gl_MATH_H_DEFAULTS], [ GNULIB_ACOSF=0; AC_SUBST([GNULIB_ACOSF]) GNULIB_ACOSL=0; AC_SUBST([GNULIB_ACOSL]) GNULIB_ASINF=0; AC_SUBST([GNULIB_ASINF]) GNULIB_ASINL=0; AC_SUBST([GNULIB_ASINL]) GNULIB_ATANF=0; AC_SUBST([GNULIB_ATANF]) GNULIB_ATANL=0; AC_SUBST([GNULIB_ATANL]) GNULIB_ATAN2F=0; AC_SUBST([GNULIB_ATAN2F]) GNULIB_CBRT=0; AC_SUBST([GNULIB_CBRT]) GNULIB_CBRTF=0; AC_SUBST([GNULIB_CBRTF]) GNULIB_CBRTL=0; AC_SUBST([GNULIB_CBRTL]) GNULIB_CEIL=0; AC_SUBST([GNULIB_CEIL]) GNULIB_CEILF=0; AC_SUBST([GNULIB_CEILF]) GNULIB_CEILL=0; AC_SUBST([GNULIB_CEILL]) GNULIB_COPYSIGN=0; AC_SUBST([GNULIB_COPYSIGN]) GNULIB_COPYSIGNF=0; AC_SUBST([GNULIB_COPYSIGNF]) GNULIB_COPYSIGNL=0; AC_SUBST([GNULIB_COPYSIGNL]) GNULIB_COSF=0; AC_SUBST([GNULIB_COSF]) GNULIB_COSL=0; AC_SUBST([GNULIB_COSL]) GNULIB_COSHF=0; AC_SUBST([GNULIB_COSHF]) GNULIB_EXPF=0; AC_SUBST([GNULIB_EXPF]) GNULIB_EXPL=0; AC_SUBST([GNULIB_EXPL]) GNULIB_EXP2=0; AC_SUBST([GNULIB_EXP2]) GNULIB_EXP2F=0; AC_SUBST([GNULIB_EXP2F]) GNULIB_EXP2L=0; AC_SUBST([GNULIB_EXP2L]) GNULIB_EXPM1=0; AC_SUBST([GNULIB_EXPM1]) GNULIB_EXPM1F=0; AC_SUBST([GNULIB_EXPM1F]) GNULIB_EXPM1L=0; AC_SUBST([GNULIB_EXPM1L]) GNULIB_FABSF=0; AC_SUBST([GNULIB_FABSF]) GNULIB_FABSL=0; AC_SUBST([GNULIB_FABSL]) GNULIB_FLOOR=0; AC_SUBST([GNULIB_FLOOR]) GNULIB_FLOORF=0; AC_SUBST([GNULIB_FLOORF]) GNULIB_FLOORL=0; AC_SUBST([GNULIB_FLOORL]) GNULIB_FMA=0; AC_SUBST([GNULIB_FMA]) GNULIB_FMAF=0; AC_SUBST([GNULIB_FMAF]) GNULIB_FMAL=0; AC_SUBST([GNULIB_FMAL]) GNULIB_FMOD=0; AC_SUBST([GNULIB_FMOD]) GNULIB_FMODF=0; AC_SUBST([GNULIB_FMODF]) GNULIB_FMODL=0; AC_SUBST([GNULIB_FMODL]) GNULIB_FREXPF=0; AC_SUBST([GNULIB_FREXPF]) GNULIB_FREXP=0; AC_SUBST([GNULIB_FREXP]) GNULIB_FREXPL=0; AC_SUBST([GNULIB_FREXPL]) GNULIB_HYPOT=0; AC_SUBST([GNULIB_HYPOT]) GNULIB_HYPOTF=0; AC_SUBST([GNULIB_HYPOTF]) GNULIB_HYPOTL=0; AC_SUBST([GNULIB_HYPOTL]) GNULIB_ILOGB=0; AC_SUBST([GNULIB_ILOGB]) GNULIB_ILOGBF=0; AC_SUBST([GNULIB_ILOGBF]) GNULIB_ILOGBL=0; AC_SUBST([GNULIB_ILOGBL]) GNULIB_ISFINITE=0; AC_SUBST([GNULIB_ISFINITE]) GNULIB_ISINF=0; AC_SUBST([GNULIB_ISINF]) GNULIB_ISNAN=0; AC_SUBST([GNULIB_ISNAN]) GNULIB_ISNANF=0; AC_SUBST([GNULIB_ISNANF]) GNULIB_ISNAND=0; AC_SUBST([GNULIB_ISNAND]) GNULIB_ISNANL=0; AC_SUBST([GNULIB_ISNANL]) GNULIB_LDEXPF=0; AC_SUBST([GNULIB_LDEXPF]) GNULIB_LDEXPL=0; AC_SUBST([GNULIB_LDEXPL]) GNULIB_LOG=0; AC_SUBST([GNULIB_LOG]) GNULIB_LOGF=0; AC_SUBST([GNULIB_LOGF]) GNULIB_LOGL=0; AC_SUBST([GNULIB_LOGL]) GNULIB_LOG10=0; AC_SUBST([GNULIB_LOG10]) GNULIB_LOG10F=0; AC_SUBST([GNULIB_LOG10F]) GNULIB_LOG10L=0; AC_SUBST([GNULIB_LOG10L]) GNULIB_LOG1P=0; AC_SUBST([GNULIB_LOG1P]) GNULIB_LOG1PF=0; AC_SUBST([GNULIB_LOG1PF]) GNULIB_LOG1PL=0; AC_SUBST([GNULIB_LOG1PL]) GNULIB_LOG2=0; AC_SUBST([GNULIB_LOG2]) GNULIB_LOG2F=0; AC_SUBST([GNULIB_LOG2F]) GNULIB_LOG2L=0; AC_SUBST([GNULIB_LOG2L]) GNULIB_LOGB=0; AC_SUBST([GNULIB_LOGB]) GNULIB_LOGBF=0; AC_SUBST([GNULIB_LOGBF]) GNULIB_LOGBL=0; AC_SUBST([GNULIB_LOGBL]) GNULIB_MODF=0; AC_SUBST([GNULIB_MODF]) GNULIB_MODFF=0; AC_SUBST([GNULIB_MODFF]) GNULIB_MODFL=0; AC_SUBST([GNULIB_MODFL]) GNULIB_POWF=0; AC_SUBST([GNULIB_POWF]) GNULIB_REMAINDER=0; AC_SUBST([GNULIB_REMAINDER]) GNULIB_REMAINDERF=0; AC_SUBST([GNULIB_REMAINDERF]) GNULIB_REMAINDERL=0; AC_SUBST([GNULIB_REMAINDERL]) GNULIB_RINT=0; AC_SUBST([GNULIB_RINT]) GNULIB_RINTF=0; AC_SUBST([GNULIB_RINTF]) GNULIB_RINTL=0; AC_SUBST([GNULIB_RINTL]) GNULIB_ROUND=0; AC_SUBST([GNULIB_ROUND]) GNULIB_ROUNDF=0; AC_SUBST([GNULIB_ROUNDF]) GNULIB_ROUNDL=0; AC_SUBST([GNULIB_ROUNDL]) GNULIB_SIGNBIT=0; AC_SUBST([GNULIB_SIGNBIT]) GNULIB_SINF=0; AC_SUBST([GNULIB_SINF]) GNULIB_SINL=0; AC_SUBST([GNULIB_SINL]) GNULIB_SINHF=0; AC_SUBST([GNULIB_SINHF]) GNULIB_SQRTF=0; AC_SUBST([GNULIB_SQRTF]) GNULIB_SQRTL=0; AC_SUBST([GNULIB_SQRTL]) GNULIB_TANF=0; AC_SUBST([GNULIB_TANF]) GNULIB_TANL=0; AC_SUBST([GNULIB_TANL]) GNULIB_TANHF=0; AC_SUBST([GNULIB_TANHF]) GNULIB_TRUNC=0; AC_SUBST([GNULIB_TRUNC]) GNULIB_TRUNCF=0; AC_SUBST([GNULIB_TRUNCF]) GNULIB_TRUNCL=0; AC_SUBST([GNULIB_TRUNCL]) dnl Assume proper GNU behavior unless another module says otherwise. HAVE_ACOSF=1; AC_SUBST([HAVE_ACOSF]) HAVE_ACOSL=1; AC_SUBST([HAVE_ACOSL]) HAVE_ASINF=1; AC_SUBST([HAVE_ASINF]) HAVE_ASINL=1; AC_SUBST([HAVE_ASINL]) HAVE_ATANF=1; AC_SUBST([HAVE_ATANF]) HAVE_ATANL=1; AC_SUBST([HAVE_ATANL]) HAVE_ATAN2F=1; AC_SUBST([HAVE_ATAN2F]) HAVE_CBRT=1; AC_SUBST([HAVE_CBRT]) HAVE_CBRTF=1; AC_SUBST([HAVE_CBRTF]) HAVE_CBRTL=1; AC_SUBST([HAVE_CBRTL]) HAVE_COPYSIGN=1; AC_SUBST([HAVE_COPYSIGN]) HAVE_COPYSIGNL=1; AC_SUBST([HAVE_COPYSIGNL]) HAVE_COSF=1; AC_SUBST([HAVE_COSF]) HAVE_COSL=1; AC_SUBST([HAVE_COSL]) HAVE_COSHF=1; AC_SUBST([HAVE_COSHF]) HAVE_EXPF=1; AC_SUBST([HAVE_EXPF]) HAVE_EXPL=1; AC_SUBST([HAVE_EXPL]) HAVE_EXPM1=1; AC_SUBST([HAVE_EXPM1]) HAVE_EXPM1F=1; AC_SUBST([HAVE_EXPM1F]) HAVE_FABSF=1; AC_SUBST([HAVE_FABSF]) HAVE_FABSL=1; AC_SUBST([HAVE_FABSL]) HAVE_FMA=1; AC_SUBST([HAVE_FMA]) HAVE_FMAF=1; AC_SUBST([HAVE_FMAF]) HAVE_FMAL=1; AC_SUBST([HAVE_FMAL]) HAVE_FMODF=1; AC_SUBST([HAVE_FMODF]) HAVE_FMODL=1; AC_SUBST([HAVE_FMODL]) HAVE_FREXPF=1; AC_SUBST([HAVE_FREXPF]) HAVE_HYPOTF=1; AC_SUBST([HAVE_HYPOTF]) HAVE_HYPOTL=1; AC_SUBST([HAVE_HYPOTL]) HAVE_ILOGB=1; AC_SUBST([HAVE_ILOGB]) HAVE_ILOGBF=1; AC_SUBST([HAVE_ILOGBF]) HAVE_ILOGBL=1; AC_SUBST([HAVE_ILOGBL]) HAVE_ISNANF=1; AC_SUBST([HAVE_ISNANF]) HAVE_ISNAND=1; AC_SUBST([HAVE_ISNAND]) HAVE_ISNANL=1; AC_SUBST([HAVE_ISNANL]) HAVE_LDEXPF=1; AC_SUBST([HAVE_LDEXPF]) HAVE_LOGF=1; AC_SUBST([HAVE_LOGF]) HAVE_LOGL=1; AC_SUBST([HAVE_LOGL]) HAVE_LOG10F=1; AC_SUBST([HAVE_LOG10F]) HAVE_LOG10L=1; AC_SUBST([HAVE_LOG10L]) HAVE_LOG1P=1; AC_SUBST([HAVE_LOG1P]) HAVE_LOG1PF=1; AC_SUBST([HAVE_LOG1PF]) HAVE_LOG1PL=1; AC_SUBST([HAVE_LOG1PL]) HAVE_LOGBF=1; AC_SUBST([HAVE_LOGBF]) HAVE_LOGBL=1; AC_SUBST([HAVE_LOGBL]) HAVE_MODFF=1; AC_SUBST([HAVE_MODFF]) HAVE_MODFL=1; AC_SUBST([HAVE_MODFL]) HAVE_POWF=1; AC_SUBST([HAVE_POWF]) HAVE_REMAINDER=1; AC_SUBST([HAVE_REMAINDER]) HAVE_REMAINDERF=1; AC_SUBST([HAVE_REMAINDERF]) HAVE_RINT=1; AC_SUBST([HAVE_RINT]) HAVE_RINTL=1; AC_SUBST([HAVE_RINTL]) HAVE_SINF=1; AC_SUBST([HAVE_SINF]) HAVE_SINL=1; AC_SUBST([HAVE_SINL]) HAVE_SINHF=1; AC_SUBST([HAVE_SINHF]) HAVE_SQRTF=1; AC_SUBST([HAVE_SQRTF]) HAVE_SQRTL=1; AC_SUBST([HAVE_SQRTL]) HAVE_TANF=1; AC_SUBST([HAVE_TANF]) HAVE_TANL=1; AC_SUBST([HAVE_TANL]) HAVE_TANHF=1; AC_SUBST([HAVE_TANHF]) HAVE_DECL_ACOSL=1; AC_SUBST([HAVE_DECL_ACOSL]) HAVE_DECL_ASINL=1; AC_SUBST([HAVE_DECL_ASINL]) HAVE_DECL_ATANL=1; AC_SUBST([HAVE_DECL_ATANL]) HAVE_DECL_CBRTF=1; AC_SUBST([HAVE_DECL_CBRTF]) HAVE_DECL_CBRTL=1; AC_SUBST([HAVE_DECL_CBRTL]) HAVE_DECL_CEILF=1; AC_SUBST([HAVE_DECL_CEILF]) HAVE_DECL_CEILL=1; AC_SUBST([HAVE_DECL_CEILL]) HAVE_DECL_COPYSIGNF=1; AC_SUBST([HAVE_DECL_COPYSIGNF]) HAVE_DECL_COSL=1; AC_SUBST([HAVE_DECL_COSL]) HAVE_DECL_EXPL=1; AC_SUBST([HAVE_DECL_EXPL]) HAVE_DECL_EXP2=1; AC_SUBST([HAVE_DECL_EXP2]) HAVE_DECL_EXP2F=1; AC_SUBST([HAVE_DECL_EXP2F]) HAVE_DECL_EXP2L=1; AC_SUBST([HAVE_DECL_EXP2L]) HAVE_DECL_EXPM1L=1; AC_SUBST([HAVE_DECL_EXPM1L]) HAVE_DECL_FLOORF=1; AC_SUBST([HAVE_DECL_FLOORF]) HAVE_DECL_FLOORL=1; AC_SUBST([HAVE_DECL_FLOORL]) HAVE_DECL_FREXPL=1; AC_SUBST([HAVE_DECL_FREXPL]) HAVE_DECL_LDEXPL=1; AC_SUBST([HAVE_DECL_LDEXPL]) HAVE_DECL_LOGL=1; AC_SUBST([HAVE_DECL_LOGL]) HAVE_DECL_LOG10L=1; AC_SUBST([HAVE_DECL_LOG10L]) HAVE_DECL_LOG2=1; AC_SUBST([HAVE_DECL_LOG2]) HAVE_DECL_LOG2F=1; AC_SUBST([HAVE_DECL_LOG2F]) HAVE_DECL_LOG2L=1; AC_SUBST([HAVE_DECL_LOG2L]) HAVE_DECL_LOGB=1; AC_SUBST([HAVE_DECL_LOGB]) HAVE_DECL_REMAINDER=1; AC_SUBST([HAVE_DECL_REMAINDER]) HAVE_DECL_REMAINDERL=1; AC_SUBST([HAVE_DECL_REMAINDERL]) HAVE_DECL_RINTF=1; AC_SUBST([HAVE_DECL_RINTF]) HAVE_DECL_ROUND=1; AC_SUBST([HAVE_DECL_ROUND]) HAVE_DECL_ROUNDF=1; AC_SUBST([HAVE_DECL_ROUNDF]) HAVE_DECL_ROUNDL=1; AC_SUBST([HAVE_DECL_ROUNDL]) HAVE_DECL_SINL=1; AC_SUBST([HAVE_DECL_SINL]) HAVE_DECL_SQRTL=1; AC_SUBST([HAVE_DECL_SQRTL]) HAVE_DECL_TANL=1; AC_SUBST([HAVE_DECL_TANL]) HAVE_DECL_TRUNC=1; AC_SUBST([HAVE_DECL_TRUNC]) HAVE_DECL_TRUNCF=1; AC_SUBST([HAVE_DECL_TRUNCF]) HAVE_DECL_TRUNCL=1; AC_SUBST([HAVE_DECL_TRUNCL]) REPLACE_CBRTF=0; AC_SUBST([REPLACE_CBRTF]) REPLACE_CBRTL=0; AC_SUBST([REPLACE_CBRTL]) REPLACE_CEIL=0; AC_SUBST([REPLACE_CEIL]) REPLACE_CEILF=0; AC_SUBST([REPLACE_CEILF]) REPLACE_CEILL=0; AC_SUBST([REPLACE_CEILL]) REPLACE_EXPM1=0; AC_SUBST([REPLACE_EXPM1]) REPLACE_EXPM1F=0; AC_SUBST([REPLACE_EXPM1F]) REPLACE_EXP2=0; AC_SUBST([REPLACE_EXP2]) REPLACE_EXP2L=0; AC_SUBST([REPLACE_EXP2L]) REPLACE_FABSL=0; AC_SUBST([REPLACE_FABSL]) REPLACE_FLOOR=0; AC_SUBST([REPLACE_FLOOR]) REPLACE_FLOORF=0; AC_SUBST([REPLACE_FLOORF]) REPLACE_FLOORL=0; AC_SUBST([REPLACE_FLOORL]) REPLACE_FMA=0; AC_SUBST([REPLACE_FMA]) REPLACE_FMAF=0; AC_SUBST([REPLACE_FMAF]) REPLACE_FMAL=0; AC_SUBST([REPLACE_FMAL]) REPLACE_FMOD=0; AC_SUBST([REPLACE_FMOD]) REPLACE_FMODF=0; AC_SUBST([REPLACE_FMODF]) REPLACE_FMODL=0; AC_SUBST([REPLACE_FMODL]) REPLACE_FREXPF=0; AC_SUBST([REPLACE_FREXPF]) REPLACE_FREXP=0; AC_SUBST([REPLACE_FREXP]) REPLACE_FREXPL=0; AC_SUBST([REPLACE_FREXPL]) REPLACE_HUGE_VAL=0; AC_SUBST([REPLACE_HUGE_VAL]) REPLACE_HYPOT=0; AC_SUBST([REPLACE_HYPOT]) REPLACE_HYPOTF=0; AC_SUBST([REPLACE_HYPOTF]) REPLACE_HYPOTL=0; AC_SUBST([REPLACE_HYPOTL]) REPLACE_ILOGB=0; AC_SUBST([REPLACE_ILOGB]) REPLACE_ILOGBF=0; AC_SUBST([REPLACE_ILOGBF]) REPLACE_ISFINITE=0; AC_SUBST([REPLACE_ISFINITE]) REPLACE_ISINF=0; AC_SUBST([REPLACE_ISINF]) REPLACE_ISNAN=0; AC_SUBST([REPLACE_ISNAN]) REPLACE_LDEXPL=0; AC_SUBST([REPLACE_LDEXPL]) REPLACE_LOG=0; AC_SUBST([REPLACE_LOG]) REPLACE_LOGF=0; AC_SUBST([REPLACE_LOGF]) REPLACE_LOGL=0; AC_SUBST([REPLACE_LOGL]) REPLACE_LOG10=0; AC_SUBST([REPLACE_LOG10]) REPLACE_LOG10F=0; AC_SUBST([REPLACE_LOG10F]) REPLACE_LOG10L=0; AC_SUBST([REPLACE_LOG10L]) REPLACE_LOG1P=0; AC_SUBST([REPLACE_LOG1P]) REPLACE_LOG1PF=0; AC_SUBST([REPLACE_LOG1PF]) REPLACE_LOG1PL=0; AC_SUBST([REPLACE_LOG1PL]) REPLACE_LOG2=0; AC_SUBST([REPLACE_LOG2]) REPLACE_LOG2F=0; AC_SUBST([REPLACE_LOG2F]) REPLACE_LOG2L=0; AC_SUBST([REPLACE_LOG2L]) REPLACE_LOGB=0; AC_SUBST([REPLACE_LOGB]) REPLACE_LOGBF=0; AC_SUBST([REPLACE_LOGBF]) REPLACE_LOGBL=0; AC_SUBST([REPLACE_LOGBL]) REPLACE_MODF=0; AC_SUBST([REPLACE_MODF]) REPLACE_MODFF=0; AC_SUBST([REPLACE_MODFF]) REPLACE_MODFL=0; AC_SUBST([REPLACE_MODFL]) REPLACE_NAN=0; AC_SUBST([REPLACE_NAN]) REPLACE_REMAINDER=0; AC_SUBST([REPLACE_REMAINDER]) REPLACE_REMAINDERF=0; AC_SUBST([REPLACE_REMAINDERF]) REPLACE_REMAINDERL=0; AC_SUBST([REPLACE_REMAINDERL]) REPLACE_ROUND=0; AC_SUBST([REPLACE_ROUND]) REPLACE_ROUNDF=0; AC_SUBST([REPLACE_ROUNDF]) REPLACE_ROUNDL=0; AC_SUBST([REPLACE_ROUNDL]) REPLACE_SIGNBIT=0; AC_SUBST([REPLACE_SIGNBIT]) REPLACE_SIGNBIT_USING_GCC=0; AC_SUBST([REPLACE_SIGNBIT_USING_GCC]) REPLACE_SQRTL=0; AC_SUBST([REPLACE_SQRTL]) REPLACE_TRUNC=0; AC_SUBST([REPLACE_TRUNC]) REPLACE_TRUNCF=0; AC_SUBST([REPLACE_TRUNCF]) REPLACE_TRUNCL=0; AC_SUBST([REPLACE_TRUNCL]) ]) # gl_LONG_DOUBLE_VS_DOUBLE # determines whether 'long double' and 'double' have the same representation. # Sets variable HAVE_SAME_LONG_DOUBLE_AS_DOUBLE to 0 or 1, and defines # HAVE_SAME_LONG_DOUBLE_AS_DOUBLE accordingly. # The currently known platforms where this is the case are: # Linux/HPPA, Minix 3.1.8, AIX 5, AIX 6 and 7 with xlc, MSVC 9. AC_DEFUN([gl_LONG_DOUBLE_VS_DOUBLE], [ AC_CACHE_CHECK([whether long double and double are the same], [gl_cv_long_double_equals_double], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM([[#include ]], [[typedef int check[sizeof (long double) == sizeof (double) && LDBL_MANT_DIG == DBL_MANT_DIG && LDBL_MAX_EXP == DBL_MAX_EXP && LDBL_MIN_EXP == DBL_MIN_EXP ? 1 : -1]; ]])], [gl_cv_long_double_equals_double=yes], [gl_cv_long_double_equals_double=no]) ]) if test $gl_cv_long_double_equals_double = yes; then AC_DEFINE([HAVE_SAME_LONG_DOUBLE_AS_DOUBLE], [1], [Define to 1 if 'long double' and 'double' have the same representation.]) HAVE_SAME_LONG_DOUBLE_AS_DOUBLE=1 else HAVE_SAME_LONG_DOUBLE_AS_DOUBLE=0 fi AC_SUBST([HAVE_SAME_LONG_DOUBLE_AS_DOUBLE]) ])