【发布时间】：2015-04-04 04:04:46
【问题描述】：
我正在使用 clang 编译器和 libc++ 标准库在 C++11 的 mac 上构建一个动态库。当我在链接到动态库的测试代码上运行 valgrind 时，我得到一块肯定丢失的内存。这是 valgrind 报告：
==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
该特定代码部分不处理我动态分配的任何内存，仅使用 STL 对象和流。我附上了头文件和 valgrind 报告的导致泄漏的方法。有人可以解释一下这里发生了什么吗？我真的很困惑。
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 仅显示 write_dimension 方法和文件开头
#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 << " ";
}
}
如果需要更多信息，请告诉我。
【问题讨论】：
-
您是否确保传入
header_data::write_dimension()的ofstream 被正确关闭并在之后被删除？另外，您是否尝试过将语句file << value << " ";拆分为多个语句和行，以找出问题是否与 ofstream 或格式化命令有关？另外，您使用的是最新的 Valgrind 版本吗？ -
上述 valgrind 报告发生在 ostream 关闭和打开的情况下。第一次运行 valgrind 时，我忘记了关闭流，我认为这就是问题所在。但问题仍然存在。
-
我正在使用 valgrind-3.10.1。我稍后会检查格式。
标签： c++ memory-leaks clang valgrind libc++