- html - 出于某种原因,IE8 对我的 Sass 文件中继承的 html5 CSS 不友好?
- JMeter 在响应断言中使用 span 标签的问题
- html - 在 :hover and :active? 上具有不同效果的 CSS 动画
- html - 相对于居中的 html 内容固定的 CSS 重复背景?
我的.c文件代码:
#include <stdio.h>
/* i had made the coding wrong on purpose. */
int main(){
int g = 10;
int h;
printf("I am %d age.\n");
printf("I am %dtall.\n", h);
return 0;
}
我运行了这段代码:gcc -Wall -g -o ex4 ex4.c
在我的终端中,这是我得到的输出:
ex4.c:8:17: warning: more '%' conversions than data arguments [-Wformat]
printf("I am %d age.\n");
~^
ex4.c:5:7: warning: unused variable 'g' [-Wunused-variable]
int g = 10;
^
ex4.c:9:28: warning: variable 'h' is uninitialized when used here
[-Wuninitialized]
printf("I am %dtall.\n", h);
^
ex4.c:6:8: note: initialize the variable 'h' to silence this warning
int h;
^
= 0
3 warnings generated.
我继续尝试使用 valgrind 检查内存泄漏:
valgrind ./ex4
这是我终端上的输出:
iPatrickMac:trying_valgrind patrick$ valgrind ./ex4
==10836== Memcheck, a memory error detector
==10836== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==10836== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==10836== Command: ./ex4
==10836==
==10836== Syscall param msg->desc.port.name points to uninitialised byte(s)
==10836== at 0x1003A834A: mach_msg_trap (in /usr/lib/system/libsystem_kernel.dylib)
==10836== by 0x1003A7796: mach_msg (in /usr/lib/system/libsystem_kernel.dylib)
==10836== by 0x1003A1485: task_set_special_port (in /usr/lib/system/libsystem_kernel.dylib)
==10836== by 0x10053D10E: _os_trace_create_debug_control_port (in /usr/lib/system/libsystem_trace.dylib)
==10836== by 0x10053D458: _libtrace_init (in /usr/lib/system/libsystem_trace.dylib)
==10836== by 0x1000A69DF: libSystem_initializer (in /usr/lib/libSystem.B.dylib)
==10836== by 0x100018A1A: ImageLoaderMachO::doModInitFunctions(ImageLoader::LinkContext const&) (in /usr/lib/dyld)
==10836== by 0x100018C1D: ImageLoaderMachO::doInitialization(ImageLoader::LinkContext const&) (in /usr/lib/dyld)
==10836== by 0x1000144A9: ImageLoader::recursiveInitialization(ImageLoader::LinkContext const&, unsigned int, char const*, ImageLoader::InitializerTimingList&, ImageLoader::UninitedUpwards&) (in /usr/lib/dyld)
==10836== by 0x100014440: ImageLoader::recursiveInitialization(ImageLoader::LinkContext const&, unsigned int, char const*, ImageLoader::InitializerTimingList&, ImageLoader::UninitedUpwards&) (in /usr/lib/dyld)
==10836== by 0x100013523: ImageLoader::processInitializers(ImageLoader::LinkContext const&, unsigned int, ImageLoader::InitializerTimingList&, ImageLoader::UninitedUpwards&) (in /usr/lib/dyld)
==10836== by 0x1000135B8: ImageLoader::runInitializers(ImageLoader::LinkContext const&, ImageLoader::InitializerTimingList&) (in /usr/lib/dyld)
==10836== Address 0x10488bdcc is on thread 1's stack
==10836== in frame #2, created by task_set_special_port (???:)
==10836==
I am 76077616 age.
==10836== Conditional jump or move depends on uninitialised value(s)
==10836== at 0x1002A64D7: __vfprintf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002CE422: __v2printf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A433D: vfprintf_l (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A2247: printf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x100000F67: main (ex4.c:9)
==10836==
==10836== Conditional jump or move depends on uninitialised value(s)
==10836== at 0x1002A8E87: __ultoa (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002CE422: __v2printf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A433D: vfprintf_l (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A2247: printf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x100000F67: main (ex4.c:9)
==10836==
==10836== Conditional jump or move depends on uninitialised value(s)
==10836== at 0x10009A142: _platform_memchr$VARIANT$Haswell (in /usr/local/Cellar/valgrind/3.13.0/lib/valgrind/vgpreload_memcheck-amd64-darwin.so)
==10836== by 0x10029E4D1: __sfvwrite (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A8898: __vfprintf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002CE422: __v2printf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A433D: vfprintf_l (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A2247: printf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x100000F67: main (ex4.c:9)
==10836==
==10836== Syscall param write(buf) points to uninitialised byte(s)
==10836== at 0x1003B047E: write$NOCANCEL (in /usr/lib/system/libsystem_kernel.dylib)
==10836== by 0x1002A3200: _swrite (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x10029BD26: __sflush (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x10029E584: __sfvwrite (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A8952: __vfprintf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002CE422: __v2printf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A433D: vfprintf_l (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A2247: printf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x100000F67: main (ex4.c:9)
==10836== Address 0x100b57b85 is 5 bytes inside a block of size 4,096 alloc'd
==10836== at 0x100098616: malloc (in /usr/local/Cellar/valgrind/3.13.0/lib/valgrind/vgpreload_memcheck-amd64-darwin.so)
==10836== by 0x10029EFD8: __smakebuf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002B3B1D: __swsetup (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002CE1BE: __v2printf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A433D: vfprintf_l (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x1002A2247: printf (in /usr/lib/system/libsystem_c.dylib)
==10836== by 0x100000F53: main (ex4.c:8)
==10836==
I am 1tall.
==10836==
==10836== HEAP SUMMARY:
==10836== in use at exit: 22,136 bytes in 160 blocks
==10836== total heap usage: 176 allocs, 16 frees, 28,280 bytes allocated
==10836==
==10836== LEAK SUMMARY:
==10836== definitely lost: 0 bytes in 0 blocks
==10836== indirectly lost: 0 bytes in 0 blocks
==10836== possibly lost: 72 bytes in 3 blocks
==10836== still reachable: 200 bytes in 6 blocks
==10836== suppressed: 21,864 bytes in 151 blocks
==10836== Rerun with --leak-check=full to see details of leaked memory
==10836==
==10836== For counts of detected and suppressed errors, rerun with: -v
==10836== Use --track-origins=yes to see where uninitialised values come from
==10836== ERROR SUMMARY: 5 errors from 5 contexts (suppressed: 4 from 4)
我很困惑为什么我的 valgrind 不显示错误行并且显示其他路径。
是我的编译有问题还是 macOS sierra 上的 valgrind 有问题?帮助大家):
这一切是什么:
==10836== Syscall param msg->desc.port.name points to uninitialised byte(s)
==10836== at 0x1003A834A: mach_msg_trap (in /usr/lib/system/libsystem_kernel.dylib)
==10836== by 0x1003A7796: mach_msg (in /usr/lib/system/libsystem_kernel.dylib)
==10836== by 0x1003A1485: task_set_special_port (in /usr/lib/system/libsystem_kernel.dylib)
==10836== by 0x10053D10E: _os_trace_create_debug_control_port (in /usr/lib/system/libsystem_trace.dylib)
==10836== by 0x10053D458: _libtrace_init (in /usr/lib/system/libsystem_trace.dylib)
==10836== by 0x1000A69DF: libSystem_initializer (in /usr/lib/libSystem.B.dylib)
==10836== by 0x100018A1A: ImageLoaderMachO::doModInitFunctions(ImageLoader::LinkContext const&) (in /usr/lib/dyld)
==10836== by 0x100018C1D: ImageLoaderMachO::doInitialization(ImageLoader::LinkContext const&) (in /usr/lib/dyld)
==10836== by 0x1000144A9: ImageLoader::recursiveInitialization(ImageLoader::LinkContext const&, unsigned int, char const*, ImageLoader::InitializerTimingList&, ImageLoader::UninitedUpwards&) (in /usr/lib/dyld)
==10836== by 0x100014440: ImageLoader::recursiveInitialization(ImageLoader::LinkContext const&, unsigned int, char const*, ImageLoader::InitializerTimingList&, ImageLoader::UninitedUpwards&) (in /usr/lib/dyld)
==10836== by 0x100013523: ImageLoader::processInitializers(ImageLoader::LinkContext const&, unsigned int, ImageLoader::InitializerTimingList&, ImageLoader::UninitedUpwards&) (in /usr/lib/dyld)
==10836== by 0x1000135B8: ImageLoader::runInitializers(ImageLoader::LinkContext const&, ImageLoader::InitializerTimingList&) (in /usr/lib/dyld)
==10836== Address 0x10488bdcc is on thread 1's stack
==10836== in frame #2, created by task_set_special_port (???:)
显示错误行的 valgrind 示例:
==5190== Use of uninitialised value of size 4
==5190== at 0x4078B2B: _itoa_word (_itoa.c:195)
==5190== by 0x407CE55: vfprintf (vfprintf.c:1619)
==5190== by 0x40831DE: printf (printf.c:35)
==5190== by 0x4052112: (below main) (libc-start.c:226)
==5190==
==5190== Conditional jump or move depends on uninitialised value(s)
==5190== at 0x4078B33: _itoa_word (_itoa.c:195)
==5190== by 0x407CE55: vfprintf (vfprintf.c:1619)
==5190== by 0x40831DE: printf (printf.c:35)
==5190== by 0x4052112: (below main) (libc-start.c:226)
==5190==
==5190== Conditional jump or move depends on uninitialised value(s)
==5190== at 0x407CC10: vfprintf (vfprintf.c:1619)
==5190== by 0x40831DE: printf (printf.c:35)
==5190== by 0x4052112: (below main) (libc-start.c:226)
==5190==
==5190== Conditional jump or move depends on uninitialised value(s)
==5190== at 0x407C742: vfprintf (vfprintf.c:1619)
==5190== by 0x40831DE: printf (printf.c:35)
==5190== by 0x4052112: (below main) (libc-start.c:226)
我怎样才能让 macOS Sierra 上的 valgrind 相应地显示错误行,而不显示其他奇怪的路径,而我不知道它们是什么。
最佳答案
C11 标准,第 §7.21.6.1 章
[..] If there are insufficient arguments for the format, the behavior is undefined. [..]
因此,您没有忽略此警告是件好事,因为此调用的结果行为是未定义。
关于c - 为什么我的 Valgrind 不显示错误行,而是显示 macOS Seirra 中的其他路径,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/46753689/
#include using namespace std; class C{ private: int value; public: C(){ value = 0;
这个问题已经有答案了: What is the difference between char a[] = ?string?; and char *p = ?string?;? (8 个回答) 已关闭
关闭。此题需要details or clarity 。目前不接受答案。 想要改进这个问题吗?通过 editing this post 添加详细信息并澄清问题. 已关闭 7 年前。 此帖子已于 8 个月
除了调试之外,是否有任何针对 c、c++ 或 c# 的测试工具,其工作原理类似于将独立函数复制粘贴到某个文本框,然后在其他文本框中输入参数? 最佳答案 也许您会考虑单元测试。我推荐你谷歌测试和谷歌模拟
我想在第二台显示器中移动一个窗口 (HWND)。问题是我尝试了很多方法,例如将分辨率加倍或输入负值,但它永远无法将窗口放在我的第二台显示器上。 关于如何在 C/C++/c# 中执行此操作的任何线索 最
我正在寻找 C/C++/C## 中不同类型 DES 的现有实现。我的运行平台是Windows XP/Vista/7。 我正在尝试编写一个 C# 程序,它将使用 DES 算法进行加密和解密。我需要一些实
很难说出这里要问什么。这个问题模棱两可、含糊不清、不完整、过于宽泛或夸夸其谈,无法以目前的形式得到合理的回答。如需帮助澄清此问题以便重新打开,visit the help center . 关闭 1
有没有办法强制将另一个 窗口置于顶部? 不是应用程序的窗口,而是另一个已经在系统上运行的窗口。 (Windows, C/C++/C#) 最佳答案 SetWindowPos(that_window_ha
假设您可以在 C/C++ 或 Csharp 之间做出选择,并且您打算在 Windows 和 Linux 服务器上运行同一服务器的多个实例,那么构建套接字服务器应用程序的最明智选择是什么? 最佳答案 如
你们能告诉我它们之间的区别吗? 顺便问一下,有什么叫C++库或C库的吗? 最佳答案 C++ 标准库 和 C 标准库 是 C++ 和 C 标准定义的库,提供给 C++ 和 C 程序使用。那是那些词的共同
下面的测试代码,我将输出信息放在注释中。我使用的是 gcc 4.8.5 和 Centos 7.2。 #include #include class C { public:
很难说出这里问的是什么。这个问题是含糊的、模糊的、不完整的、过于宽泛的或修辞性的,无法以目前的形式得到合理的回答。如需帮助澄清此问题以便重新打开它,visit the help center 。 已关
我的客户将使用名为 annoucement 的结构/类与客户通信。我想我会用 C++ 编写服务器。会有很多不同的类继承annoucement。我的问题是通过网络将这些类发送给客户端 我想也许我应该使用
我在 C# 中有以下函数: public Matrix ConcatDescriptors(IList> descriptors) { int cols = descriptors[0].Co
我有一个项目要编写一个函数来对某些数据执行某些操作。我可以用 C/C++ 编写代码,但我不想与雇主共享该函数的代码。相反,我只想让他有权在他自己的代码中调用该函数。是否可以?我想到了这两种方法 - 在
我使用的是编写糟糕的第 3 方 (C/C++) Api。我从托管代码(C++/CLI)中使用它。有时会出现“访问冲突错误”。这使整个应用程序崩溃。我知道我无法处理这些错误[如果指针访问非法内存位置等,
关闭。这个问题不符合Stack Overflow guidelines .它目前不接受答案。 我们不允许提问寻求书籍、工具、软件库等的推荐。您可以编辑问题,以便用事实和引用来回答。 关闭 7 年前。
已关闭。此问题不符合Stack Overflow guidelines 。目前不接受答案。 要求我们推荐或查找工具、库或最喜欢的场外资源的问题对于 Stack Overflow 来说是偏离主题的,因为
我有一些 C 代码,将使用 P/Invoke 从 C# 调用。我正在尝试为这个 C 函数定义一个 C# 等效项。 SomeData* DoSomething(); struct SomeData {
这个问题已经有答案了: Why are these constructs using pre and post-increment undefined behavior? (14 个回答) 已关闭 6
我是一名优秀的程序员,十分优秀!