2015-04-04 152 views
2

我正在使用clang编译器和libC++标准库在C++ 11的mac上构建动态库。当我在我的测试代码上运行valgrind时,链接到我的动态库,我得到一块肯定丢失的内存。这里是Valgrind的报告:用户泄漏,libC++泄漏或误报

==45659== 36 bytes in 1 blocks are definitely lost in loss record 57 of 228 
==45659== at 0x66BB: malloc (vg_replace_malloc.c:300) 
==45659== by 0x31EAB0: __Balloc_D2A (in /usr/lib/system/libsystem_c.dylib) 
==45659== by 0x31F2A5: __d2b_D2A (in /usr/lib/system/libsystem_c.dylib) 
==45659== by 0x31BED6: __dtoa (in /usr/lib/system/libsystem_c.dylib) 
==45659== by 0x3438A9: __vfprintf (in /usr/lib/system/libsystem_c.dylib) 
==45659== by 0x36A2DA: __v2printf (in /usr/lib/system/libsystem_c.dylib) 
==45659== by 0x34FF66: _vsnprintf (in /usr/lib/system/libsystem_c.dylib) 
==45659== by 0x34FFC5: vsnprintf_l (in /usr/lib/system/libsystem_c.dylib) 
==45659== by 0x34057A: snprintf_l (in /usr/lib/system/libsystem_c.dylib) 
==45659== by 0x10C75A: std::__1::num_put<char, std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> > >::do_put(std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> >, std::__1::ios_base&, char, double) const (in /usr/lib/libc++.1.dylib) 
==45659== by 0xF3221: std::__1::basic_ostream<char, std::__1::char_traits<char> >::operator<<(double) (in /usr/lib/libc++.1.dylib) 
==45659== by 0x12102: lmpsdata::header_data::write_dimension(std::__1::basic_ofstream<char, std::__1::char_traits<char> >&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) (header_data.cpp:75) 
==45659== 
==45659== LEAK SUMMARY: 
==45659== definitely lost: 36 bytes in 1 blocks 
==45659== indirectly lost: 0 bytes in 0 blocks 
==45659==  possibly lost: 0 bytes in 0 blocks 
==45659== still reachable: 18,340 bytes in 215 blocks 
==45659==   suppressed: 25,274 bytes in 374 blocks 

这特定的代码段不涉及我是动态分配的任何内存,只有STL对象和流使用。我已经将头文件和valgrind报告的方法连接起来导致泄漏。有人能解释一下这里发生了什么吗?我感到非常困惑。如果需要了解更多信息,请让我知道

header_data.h

#ifndef ____header_data__ 
#define ____header_data__ 

#include <string> 
#include <fstream> 
#include <cstdint> 
#include <vector> 
#include <map> 

namespace lmpsdata { 
class header_data 
{//LAMMPS header information 
    //only the point particle header information has been implemented 
    //since the current atom base class is designed for point particles only 
public: 
    header_data():xdim(2), ydim(2), zdim(2), tiltdim(3) {} 
    //methods 
    void read(const std::string &, const std::string &); 
    void write(std::ofstream &, const std::string &); //this write command will replace the one 
    std::string check_header_keyword(const std::string &, bool &); 
    uint64_t get(const std::string&); 
    std::vector<double>& get_vector(const std::string&); 
    void set(const std::string&, uint64_t); 
    void set_vector(const std::string&, std::vector<double>&); 

private: 
    //methods 
    void read_dimension(const std::string&, const std::string&); 
    void write_dimension(std::ofstream&, const std::string&); 

    //members 
    uint64_t atomnum; 
    uint64_t bondnum; 
    uint64_t anglenum; 
    uint64_t dihedralnum; 
    uint64_t impropernum; 
    uint64_t atomtypenum; 
    uint64_t bondtypenum; 
    uint64_t angletypenum; 
    uint64_t dihedraltypenum; 
    uint64_t impropertypenum; 
    uint64_t extrabondnum; 

    std::vector<double> xdim; 
    std::vector<double> ydim; 
    std::vector<double> zdim; 
    std::vector<double> tiltdim;//for use with triclinic system 

    std::map<std::string, uint64_t&> int_map { 
     {"atoms", atomnum}, 
     {"bonds", bondnum}, 
     {"angles", anglenum}, 
     {"dihedrals", dihedralnum}, 
     {"impropers", impropernum}, 
     {"atom types", atomtypenum}, 
     {"bond types", bondtypenum}, 
     {"angle types", angletypenum}, 
     {"dihedral types", dihedraltypenum}, 
     {"improper types", impropertypenum}, 
     {"extra bond per atom", extrabondnum}, 
    }; 
    std::map<std::string, std::vector<double>&> v_map { 
     {"xlo xhi", xdim}, 
     {"ylo yhi", ydim}, 
     {"zlo zhi", zdim}, 
     {"xy xz yz", tiltdim} 
    }; 
}; 
} 
#endif /* defined(____header_data__) */ 

lmpsdata.cpp仅write_dimension方法和文件的开头显示

#include "header_data.h" 
#include <stdexcept> 
using namespace lmpsdata; 
void header_data::write_dimension(std::ofstream &file, const std::string& keyword) 
{ 
    std::vector<double>& data = v_map.at(keyword); 
    for (auto value: data) { 
     file << value << " "; 
    } 
} 

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您是否已确认您传入'header_data :: write_dimension()'的流正确关闭并在事后删除?另外,你是否尝试将语句'file << value <<“”;'分解为多个语句和行,以查明问题是否与ofstream或格式化命令相关?另外,您是否使用最近的Valgrind版本? – oliver 2015-04-07 14:00:02

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上面的valgrind报告发生在ostream关闭和左侧打开的情况下。我第一次跑valgrind,我忘了关闭流,我认为这是问题。但问题仍然存在。 – 2015-04-21 16:24:56

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我正在使用valgrind-3.10.1。稍后我会检查格式。 – 2015-04-21 16:50:34

回答

1

你还没有提到你正在使用的OSX和valgrind的确切版本。我一直无法完全重现我使用的版本(OSX 10.10; valgrind HEAD == Valgrind-3.11.0.SVN)。

这不是在C++标准库中,而是在C库中。您应该能够重现它(几乎相同)用简单的代码:

#include <stdio.h> 
#include <xlocale.h> 

int 
main(int argc, char **argv) 
{ 
    locale_t loc = newlocale(LC_NUMERIC_MASK, "C", (locale_t)0); 
    double d = 22.22; 
    char buffer[1024]; 
    snprintf_l(buffer, 1024, loc, "%f\n", d); 
    printf("%s", buffer); 
    freelocale(loc); 
} 

valgrind --show-leak-kinds=all --leak-check=full ./leak运行我看到一些“仍可达”泄漏(你应该表现在这种情况下,实际泄漏):

==26151== 32 bytes in 1 blocks are still reachable in loss record 28 of 85 
==26151== at 0x10000850B: malloc (in /usr/local/Cellar/valgrind/HEAD/lib/valgrind/vgpreload_memcheck-amd64-darwin.so) 
==26151== by 0x1002BC7DF: __Balloc_D2A (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002B9533: __rv_alloc_D2A (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002B9B3A: __dtoa (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002E1D52: __vfprintf (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x10030A9AE: __v2printf (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002EF154: _vsnprintf (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002EF1B3: vsnprintf_l (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002DF5F7: snprintf_l (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x100000ECA: main (leak.cpp:10) 
==26151== 
==26151== 36 bytes in 1 blocks are still reachable in loss record 30 of 85 
==26151== at 0x10000850B: malloc (in /usr/local/Cellar/valgrind/HEAD/lib/valgrind/vgpreload_memcheck-amd64-darwin.so) 
==26151== by 0x1002BC7DF: __Balloc_D2A (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002BD055: __d2b_D2A (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002B986B: __dtoa (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002E1D52: __vfprintf (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x10030A9AE: __v2printf (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002EF154: _vsnprintf (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002EF1B3: vsnprintf_l (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002DF5F7: snprintf_l (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x100000ECA: main (leak.cpp:10) 
==26151== 
==26151== 80 bytes in 1 blocks are still reachable in loss record 47 of 85 
==26151== at 0x10000850B: malloc (in /usr/local/Cellar/valgrind/HEAD/lib/valgrind/vgpreload_memcheck-amd64-darwin.so) 
==26151== by 0x1002BC736: __Balloc_D2A (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002BD055: __d2b_D2A (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002B986B: __dtoa (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002E1D52: __vfprintf (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x10030A9AE: __v2printf (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002EF154: _vsnprintf (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002EF1B3: vsnprintf_l (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x1002DF5F7: snprintf_l (in /usr/lib/system/libsystem_c.dylib) 
==26151== by 0x100000ECA: main (leak.cpp:10) 

我会对它进行抑制,因为它几乎毫无疑问不是真正的泄漏,完全不受你的控制。

看着已发布的OSX libc source,我看不到错误出现在哪里 - 320和后来的所有看起来都不错;底层代码似乎在必要时分配和释放。但是,这个错误可能已经被引入并修复,因为我没有对所有来源进行详尽的拖网。有问题的文件是vfprintf.c,您正在查看dtoaresult作业&空闲。

要确定您的libc的版本,你可以这样做:

$ otool -l /usr/lib/system/libsystem_c.dylib | grep -A5 ID_ 

在我的系统我得到的输出:

  cmd LC_ID_DYLIB 
     cmdsize 64 
     name /usr/lib/system/libsystem_c.dylib (offset 24) 
    time stamp 1 Thu Jan 1 01:00:01 1970 
     current version 1044.10.1 
compatibility version 1.0.0 

997,我想,是小牛队(10.9)。我不知道他们是否在特拉维斯时间框架的某一时刻在代码中引入了泄漏,然后对其进行了修复 - 在__vfprintf例程中似乎没有代码路径,这些代码路径实际上在任何已发布的源代码中都有泄漏。

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我在小牛(10.9)中,libsystem_c.dylib的版本是997.90.3。当我在valgrind中运行代码时,我没有发现任何明显的泄漏,只有4个仍然可以访问,它们与你的一样。我认为你的权利可能不是真正的泄漏。我想知道这是否是valgrind-3.10.1和C++ 11的问题。 – 2015-04-21 16:49:17

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valgrind 3.10.1误报漏洞很容易造成问题,因为它无法正确跟踪分配情况 - 我已经看到了其中的一部分,通常系统级别的压缩文件用于防止报告这些泄漏。 – Petesh 2015-04-21 17:56:09

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谢谢我将研究如何设置一个压缩文件。 – 2015-04-29 00:13:51