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From: "adrian.hawryluk at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/46908] New: printf not handling printing of double correctly in certain cases Date: Sun, 12 Dec 2010 16:12:00 -0000 [thread overview] Message-ID: <bug-46908-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46908 Summary: printf not handling printing of double correctly in certain cases Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned@gcc.gnu.org ReportedBy: adrian.hawryluk@gmail.com Host: Windows XP SP2 Target: mingw32 Build: 4.5.0 This is a weird one. Under different compile options, it does it wrong in different ways. :) #include <stdio.h> #include <math.h> void printld(long double* pld) { int i; printf("*%p = ", pld); for (i = 0; i < sizeof(long double); ++i) { printf("%02x ", ((unsigned char*)pld)[i]); } printf("\n"); } int main() { long double number1 = 1.0; long double number2 = 1.0; printf ("%lf, %lf\n", number1, number2); printf ("Enter number1: "); scanf ("%lf", &number1); printf ("Enter number2: "); scanf ("%lf", &number2); printf ("%lf, %lf\n", number1, number2); printf ("%lf, %lf\n", number1, number1); printld(&number1); printld(&number2); return 0; } C:\tmp>gcc -o tmp.exe file.c C:\tmp>tmp 0.000000, 0.000000 Enter number1: 3 Enter number2: 4 3.000000, 0.000000 3.000000, 0.000000 *0022FF30 = 00 00 00 00 00 00 08 40 ff 3f 00 00 *0022FF20 = 00 00 00 00 00 00 10 40 ff 3f 00 00 C:\tmp>gcc -std=c99 -o tmp.exe file.c C:\tmp>tmp 1.000000, 1.000000 Enter number1: 3 Enter number2: 4 0.000000, 0.000000 0.000000, 0.000000 *0022ff30 = 00 00 00 00 00 00 08 40 ff 3f 00 00 *0022ff20 = 00 00 00 00 00 00 10 40 ff 3f 00 00 There was even a way of printing the same variable (number1) twice on a line and it would output it twice. That is why I had put in: printf ("%lf, %lf\n", number1, number1); as a test, but it didn't show up in this test code. C:\tmp>gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=c:/mingw/bin/../libexec/gcc/mingw32/4.5.0/lto-wrapper.exe Target: mingw32 Configured with: ../gcc-4.5.0/configure --enable-languages=c,c++,ada,fortran,objc,obj-c++ --disable-sjlj-exceptions --with-dwarf2 --enable-shared --enable-libgomp --disable-win32-registry --enable-libstdcxx-debug --enable-version-specific-runtime-libs --disable-werror --build=mingw32 --prefix=/mingw Thread model: win32 gcc version 4.5.0 (GCC) -- A
next reply other threads:[~2010-12-12 16:12 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-12-12 16:12 adrian.hawryluk at gmail dot com [this message] 2010-12-12 16:51 ` [Bug c/46908] " schwab@linux-m68k.org 2010-12-12 17:32 ` manu at gcc dot gnu.org 2010-12-12 22:53 ` adrian.hawryluk at gmail dot com 2010-12-12 22:55 ` adrian.hawryluk at gmail dot com 2010-12-12 23:09 ` adrian.hawryluk at gmail dot com 2010-12-13 18:28 ` [Bug target/46908] " jsm28 at gcc dot gnu.org
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