# # Determine if the printf() functions have the %a format character. # This is modified from: # http://www.gnu.org/software/ac-archive/htmldoc/ac_cxx_have_ext_slist.html AC_DEFUN([AC_C_PRINTF_A], [AC_CACHE_CHECK([if printf has the %a format character],[llvm_cv_c_printf_a], [AC_LANG_PUSH([C]) AC_RUN_IFELSE([ AC_LANG_PROGRAM([[ #include <stdio.h> #include <stdlib.h> ]],[[ volatile double A, B; char Buffer[100]; A = 1; A /= 10.0; sprintf(Buffer, "%a", A); B = atof(Buffer); if (A != B) return (1); if (A != 0x1.999999999999ap-4) return (1); return (0);]])], llvm_cv_c_printf_a=yes, llvmac_cv_c_printf_a=no, llvmac_cv_c_printf_a=no) AC_LANG_POP([C])]) if test "$llvm_cv_c_printf_a" = "yes"; then AC_DEFINE([HAVE_PRINTF_A],[1],[Define to have the %a format string]) fi ])