fprintf内存泄漏

Question

我正在使用XCode 4.2.1中的Instruments来查找一些内存泄漏.我发现了一个非常奇怪的(至少对我而言)内存泄漏:(该函数values_table_get_value返回一个double,并且output = stdout)

这两个问题是:它是真正的内存泄漏吗？我该如何清理它？(fprintf格式%.3f错了double？

为了表明泄漏是在fprintf中,我将函数的返回值更改为5.0:

并将返回值移动到临时变量:

更确切地说,这是一张asm代码的图片,显示泄漏是:

我做了一个非常简单的测试:使用sprintf+ 打印fprintf,但是我在sprintf上得到了泄漏:

我也尝试printf直接使用,我得到它的泄漏.

我真的认为问题在于格式.

最后的尝试,表明没有任何与我的功能相关的东西:

只是为了检查,我用valgrind执行:( values_table_print是函数名) valgrind --leak-check=full --show-reachable=yes ./leastsquares

我的软件版本:valgrind --version:valgrind-3.7.0 gcc --version i686-apple-darwin11-llvm-gcc-4.2(GCC)4.2.1(基于Apple Inc. build 5658)(LLVM build 2336.1.00 )

Answer 1

不要浪费时间调试

你的设置可能有一个糟糕的gcc或valgrind构建或只是不是最新的.

我刚尝试过:

gcc -o junk /tmp/junk.cpp && ~/src/valgrind/coregrind/valgrind --leak-check=full --show-reachable=yes /tmp/junk

在下面的代码片段中

#include <stdio.h>

int main()
{
    printf( "%.3f", 3.0 );
}

组态

• OSX 10.7.2
• 的valgrind-3.7.0.SVN

• gcc版本4.2.1(基于Apple Inc. build 5658)(LLVM build 2335.15.00)

  使用内置规格.目标:i686-apple-darwin11配置:/private/var/tmp/llvmgcc42/llvmgcc42-2335.15~25/src/configure --disable-checking --enable-werror --prefix =/Developer/usr/llvm-gcc -4.2 --mandir =/share/man --enable-languages = c,objc,c ++,obj-c ++ --program-prefix = llvm- --program-transform-name =/^ [cg] [^ .- ]*$/s/$/ - 4.2/--with-slibdir =/usr/lib --build = i686-apple-darwin11 --enable-llvm =/private/var/tmp/llvmgcc42/llvmgcc42-2335.15~25/dst-llvmCore/Developer/usr/local --program-prefix = i686-apple-darwin11- --host = x86_64-apple-darwin11 --target = i686-apple-darwin11 --with-gxx-include-dir = /usr/include/c++/4.2.1线程模型:posix gcc版本4.2.1(基于Apple Inc. build 5658)(LLVM build 2335.15.00)

Valgrind输出

==58980== Memcheck, a memory error detector
==58980== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al.
==58980== Using Valgrind-3.7.0.SVN and LibVEX; rerun with -h for copyright info
==58980== Command: /tmp/junk
==58980== 
--58980-- /tmp/junk:
--58980-- dSYM directory is missing; consider using --dsymutil=yes
UNKNOWN task message [id 3229, to mach_task_self(), reply 0x2503]
UNKNOWN task message [id 3229, to mach_task_self(), reply 0x2503]
UNKNOWN task message [id 3414, to mach_task_self(), reply 0x2503]
--58980-- WARNING: unhandled syscall: unix:357
--58980-- You may be able to write your own handler.
--58980-- Read the file README_MISSING_SYSCALL_OR_IOCTL.
--58980-- Nevertheless we consider this a bug.  Please report
--58980-- it at http://valgrind.org/support/bug_reports.html.
3.000==58980== 
==58980== HEAP SUMMARY:
==58980==     in use at exit: 0 bytes in 0 blocks
==58980==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==58980== 
==58980== All heap blocks were freed -- no leaks are possible
==58980== 
==58980== For counts of detected and suppressed errors, rerun with: -v
==58980== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)