Program Runs Fine for Hours and Eventually Seg Faults with Memory Address 0x10 [closed]

Tag: c++,c,memory,arm

So I've been tracking some memory issue for the longest time. I'm coding in C++ and I can see that my program mostly works. I am monitoring my resources and I dont think I have a memory leak because my memory used stays below 12% (I'm on a system with 256MB memory). I can let this thing run for hours and it works but eventually it segfaults.

It is hard to anaylize this issue because it takes so long for an issue to actually come up. It just crashed after running it in a debugger all day and I can see that I am doing some work on what should be a valid pointer address.

  sprintf(asciihex, "%x", var[c] & MASK);  //Where var is a pointer
                                           //MASK is 0xff

I know this works because my program runs with valid info for hours, but when the program crashes, instead of my var being a valid pointer (0xbb6b03408), the memory address is (0x10).

Also other variables (it is part of a struct) are actually NULLed. So I am trying to figure out what is going on here. My code has a check for NULL pointers and skips over them but 0x10 isn't considered NULL so it breaks. I've seen other values like 0x15 and 0x18 so I dont want to just add more checks for those, I want to find the root cause.

Any suggestions would be great!

Best How To :

I predict that your struct is being dynamically allocated via new or malloc and someone is either eating the std::bad_alloc exception without handling it or ignoring a NULL return.

An address of 0x10 is almost certainly NULL plus the struct member offset. That would also explain the zeroed fields because most operating systems map a virtual zero page at NULL.

To add onto this, if the code is being compiled without C++ exception handling, I often see it doesn't expect NULL returns from new calls. That's because normally a failed memory allocation would throw the exception instead of returning a value.

You can't just turn off exception handling in the compiler without fixing the code as well.

scanf get multiple values at once

c,char,segmentation-fault,user-input,scanf

I'm not saying that it cannot be done using scanf(), but IMHO, that's not the best way to do it. Instead, use fgets() to read the whole like, use strtok() to tokenize the input and then, based on the first token value, iterate over the input string as required. A...

Add more features to stack container

c++,visual-c++,stl

If this is interview question or something , and you have to do it anyways , you can do this like ,below code . derive from std::stack , and overload [] operator #include <iostream> #include <algorithm> #include <stack> #include <exception> #include <stdexcept> template <typename T> class myStack:public std::stack<T> { public:...

How to read string until two consecutive spaces?

c,format,sscanf,c-strings

The scanf family of functions are good for simple parsing, but not for more complicated things like you seem to do. You could probably solve it by using e.g. strstr to find the comment starter "//", terminate the string there, and then remove trailing space....

Method returning std::vector>

c++

Your error is actually coming from: array.push_back(day); This tries to put a copy of day in the vector, which is not permitted since it is unique. Instead you could write array.push_back( std::move(day) ); however the following would be better, replacing auto day...: array.emplace_back(); ...

dispatch response packet according to packet sequence id

c++,boost,boost-asio

You could use std::promise and std::future (or their boost counterparts if your are not yet on C++11). The idea is to store a std::shared_ptr<std::promise<bool>> with the current sequence id as a key in the map whenever a request is sent. In the blocking send function you wait for the corresponding...

OpenCV - Detection of moving object C++

c++,opencv

Plenty of solutions are possible. A geometric approach would detect that the one moving blob is too big to be a single passenger car. Still, this may indicate a car with a caravan. That leads us to another question: if you have two blobs moving close together, how do you...

Copy text and placeholders, variables to the clipboard

c++,qt,clipboard

You're not using the function setText correctly. The canonical prototype is text(QString & subtype, Mode mode = Clipboard) const from the documentation. What you want to do is assemble your QString ahead of time and then use that to populate the clipboard. QString message = QString("Just a test text. And...

Confused about returns in stack template

c++,templates,generic-programming

This depends on what you want the behaviour (protocol) of your class to be. Since you're logging into the error stream there, I assume you consider this an error condition to call pop() on an empty stack. The standard C++ way of signalling errors is to throw an exception. Something...

Infinite loop with fread

c,arrays,loops,malloc,fread

If you're "trying to allocate an array 64 bytes in size", you may consider uint8_t Buffer[64]; instead of uint8_t *Buffer[64]; (the latter is an array of 64 pointers to byte) After doing this, you will have no need in malloc as your structure with a 64 bytes array inside is...

Get an ordered list of files in a folder

c++,boost,boost-filesystem

The fanciest way I've seen to perform what you want is straight from the boost filesystem tutorial. In this particular example, the author appends the filename/directory to the vector and then utilizes a std::sort to ensure the data is in alphabetical order. Your code can easily be updated to use...

Segmentation fault with generating an RSA and saving in ASN.1/DER?

c,openssl,cryptography,rsa

pub_l = malloc(sizeof(pub_l)); is simply not needed. Nor is priv_l = malloc(sizeof(priv_l));. Remove them both from your function. You should be populating your out-parameters; instead you're throwing out the caller's provided addresses to populate and (a) populating your own, then (b) leaking the memory you just allocated. The result is...

How can I tell clang-format to follow this convention?

c++,clang-format

Removing BreakBeforeBraces: Allman Seems to do what you want (for me). I'm using SVN clang though. Although you probably wanted it there for a reason. According to the clang-format docs, the AllowShortBlocksOnASingleLine should do exactly what you want (regardless of brace style). This might be a bug in clang-format....

MFC visual c++ LNK2019 link error

c++,mfc

The header file provides enough information to let you declare variables. And for that matter to just compile (but not link) code. When you link, the linker has to resolve e.g. function references such as a reference to ServerConnection::getLicenceRefused, by bringing in the relevant machine code. You have to tell...

Disadvantages of calling realloc in a loop

c,memory-management,out-of-memory,realloc

When you allocate/deallocate memory many times, it may create fragmentation in the memory and you may not get big contiguous chunk of the memory. When you do a realloc, some extra memory may be needed for a short period of time to move the data. If your algorithm does...

Reverse ^ operator for decryption

c,algorithm,security,math,encryption

This is not a power operator. It is the XOR operator. The thing that you notice for the XOR operator is that x ^ k ^ k == x. That means that your encryption function is already the decryption function when called with the same key and the ciphertext instead...

Same function with and without template

c++,c++11

The main reason to do something like this is to specialize void integerA(int x) to do something else. That is, if the programmer provides as input argument an int to member function abc::integerA then because of the C++ rules instead of instantiating the template member function the compiler would pick...

Does realloc() invalidate all pointers?

c,pointers,dynamic-memory-allocation,behavior,realloc

Yes, ptr2 is unaffected by realloc(), it has no connection to realloc() call whatsoever(as per the current code). However, FWIW, as per the man page of realloc(), (emphasis mine) The realloc() function returns a pointer to the newly allocated memory, which is suitably aligned for any kind of variable and...

C++11 Allocation Requirement on Strings

c++,string,c++11,memory,standards

Section 21.4.1.5 of the 2011 standard states: The char-like objects in a basic_string object shall be stored contiguously. That is, for any basic_string object s, the identity &*(s.begin() + n) == &*s.begin() + n shall hold for all values of n such that 0 <= n < s.size(). The two...

Type function that returns a tuple of chosen types

c++,templates,c++11,metaprogramming

You can do this without recursion by simply expanding the parameter pack directly into a std::tuple: template<My_enum... Enums> struct Tuple { using type = std::tuple<typename Bind_type<Enums>::type...>; }; To answer your question more directly, you can declare a variadic primary template, then write two specializations: for when there are at least...

Translating a character array into a integer string in C++

c++,arrays,string

If you want a sequence of int, then use a vector<int>. Using the key_char string, the values of the chars in it will serve as the initial value of the ints. std::vector<int> key_num(key_char.begin(), key_char.end()); Then, iterate over each character of key_num and convert it to the equivalent int value for...

Galois LFSR - how to specify the output bit number

c,prng,shift-register

If you need bit k (k = 0 ..15), you can do the following: return (lfsr >> k) & 1; This shifts the register kbit positions to the right and masks the least significant bit....

Passing something as this argument discards qualifiers

c++,c++11

There are no operator[] of std::map which is const, you have to use at or find: template<> struct Record::getDispatcher<std::string> { static std::string impl(Record const& rec, std::string& const field) { return rec.fieldValues_.at(field); // throw if field is not in map. } }; or template<> struct Record::getDispatcher<std::string> { static std::string impl(Record const&...

C programming - Confusion regarding curly braces

c,scope

The only difference between the two is the scope of the else. Without the braces, it spans until the end of the full statement, which is the next ;, i.e the next line: else putchar(ch); /* end of else */ lastch = ch; /* outside of if-else */ With the...

Strings vs binary for storing variables inside the file format

c++,file,hdf5,dataformat

Speaking as someone who's had to do exactly what you're talking about a number of time, rr got it basically right, but I would change the emphasis a little. For file versioning, text is basically the winner. Since you're using an hdf5 library, I assume both serializing and parsing are...

C++ template template

c++,templates

Your issue is that std::deque (and other standard containers) doesn't just take a single template argument. As well as the stored type, you can specify an allocator functor type to use. If you don't care about these additional arguments, you can just take a variadic template template and be on...

What does `strcpy(x+1, SEQX)` do?

c,strcpy

The pointer + offset notation is used as a convenient means to reference memory locations. In your case, the pointer is provided by malloc() after allocating sufficient heap memory, and represents an array of M + 2 elements of type char, thus the notation as used in your code represents...

Marshal struct in struct from c# to c++

c#,c++,marshalling

Change this: [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 36)] private string iu; to this: [MarshalAs(UnmanagedType.LPStr)] private string iu; Note that this code is good only to pass a string in the C#->C++ direction. For the opposite direction (C++->C#) it is more complex, because C# can't easily deallocate C++ allocated memory. Other important thing:...

Test if string represents “yyyy-mm-dd”

c++,command-line-arguments

If you can use boost library you could simple do it like this: string date("2015-11-12"); string format("%Y-%m-%d"); date parsedDate = parser.parse_date(date, format, svp); You can read more about this here. If you want a pure C++ solution you can try using struct tm tm; std::string s("2015-11-123"); if (strptime(s.c_str(), "%Y-%m-%d", &tm))...

C++ & Qt: Random string from an array area

c++,arrays,string,qt,random

You should use the random header. #include <random> std::default_random_engine generator; std::uniform_int_distribution dist(0, 5); int StringIndex = dist(generator); std::string ChosenString = characters[StringIndex]; The above will generate a random index into your array. If you want to limit the range, change the constructor of dist, for example (dist(0,2) would only allow for...

Validate case pattern (isupper/islower) on user input string

c++,user-input

The simplest thing you can do is to use a for/while loop. A loop will basically repeat the same instruction for a number of n steps or until a certain condition is matched. The solution provided is pretty dummy, if you want to read the first name and last name...

Issue when use two type-cast operators in template class

c++

What you're trying to do makes little sense. We have subclass<int>. It is convertible to int&, but also to a lot of other reference types. char&. bool&. double&. The ambiguity arises from the fact that all the various overloads for operator<< that take any non-template argument are viable overload candidates...

Undefined behaviour or may be something with memset

c++,undefined-behavior

The A[32] in the method is actually just a pointer to A. Therefore, sizeof is the size of *int. Take the following test code: void szof(int A[32]) { std::cout << "From method: " << sizeof(A) << "\n"; } int main(int argc, char *argv[]) { int B[32]; std::cout << "From main:...

create vector of objects on the stack ? (c++)

c++,vector,heap-memory

Yes, those objects still exist and you must delete them. Alternatively you could use std::vector<std::unique_ptr<myObject>> instead, so that your objects are deleted automatically. Or you could just not use dynamic allocation as it is more expensive and error-prone. Also note that you are misusing reserve. You either want to use...

Checking value of deleted object

c++

It is very bad, accessing deleted objects as if they were not deleted will in the general case crash. There is no guarantee that the memory is still mapped inside the process and it could result in a virtual memory page fault. It is also likely that the memory will...

How can I access the members of a subclass from a superclass with a different constructor?

c++,inheritance,constructor,subclass,superclass

This map: typedef map<string, Object> obj_map; only stores Object objects. When you try to put an Image in, it is sliced down and you lose everything in the Image that was not actually part of Object. The behaviour that you seem to be looking for is called polymorphism. To activate...

How does this code print odd and even?

c,if-statement,macros,logic

In binary any numbers LSB (Least Significant Bit) is set or 1 means the number is odd, and LSB 0 means the number is even. Lets take a look: Decimal binary 1 001 (odd) 2 010 (even) 3 011 (odd) 4 100 (even) 5 101 (odd) SO, the following line...

Why are shaders and programs stored as integers in OpenGL?

c++,opengl,opengl-es,integer,shader

These integers are handles.This is a common idiom used by many APIs, used to hide resource access through an opaque level of indirection. OpenGL is effectively preventing you from accessing what lies behind the handle without using the API calls. From Wikipedia: In computer programming, a handle is an abstract...

C++ Isn't this a useless inline declaration?

c++,inline,private,member,protected

The Compiler can Access everything. The restrictions are only valid for the programmer. This means there are no restrictions for the Compiler to Access any variables! At the end every variable is just translated to an address which can be accessed. So for the Compiler it is no Problem to...

Explicit instantiation of class template not instantiating constructor

c++,templates,constructor,explicit-instantiation

When the constructor is a template member function, they are not instantiated unless explicitly used. You would see the code for the constructor if you make it a non-template member function. template<typename T> class test { public: /*** template<typename T> test(T param) { parameter = param; }; ***/ test(T param)...

Is there Predefined-Macros define about byte order in armcc

c,armcc,predefined-macro

Well according to this page: http://www.keil.com/support/man/docs/armccref/armccref_BABJFEFG.htm You have __BIG_ENDIAN which is defined when compiling for a big endian target....

opencv window not refreshing at mouse callback

c++,opencv

your code works for me. But you used cv::waitKey(0) which means that the program waits there until you press a keyboard key. So try pressing a key after drawing, or use cv::waitKey(30) instead. If this doesnt help you, please add some std::cout in your callback function to verify it is...

.cpp:23: error: cannot convert ‘std::string’ to ‘const char’ for argument ‘1’ to ‘int atoi(const char)’

c++,string

Use stoi, it's the modern C++ version of C's atoi. Update: Since the original answer text above the question was amended with the following error message: ‘stoi’ was not declared in this scope Assuming this error was produced by g++ (which uses that wording), this can have two different causes:...

Can python script know the return value of C++ main function in the Android enviroment

python,c++

For your android problem you can use fb-adb which "propagates program exit status instead of always exiting with status 0" (preferred), or use this workaround (hackish... not recommended for production use): def run_exe_return_code(run_cmd): process=subprocess.Popen(run_cmd + '; echo $?',stdout=subprocess.PIPE,shell=True) (output,err)=process.communicate() exit_code = process.wait() print output print err print exit_code return exit_code...

Implicit use of initializer_list

c++,c++11,initializer-list

Your program is not ill-formed because <vector> is guaranteed to include <initializer_list> (the same is true for all standard library containers) §23.3.1 [sequences.general] Header <vector> synopsis #include <initializer_list> ... Searching the standard for #include <initializer_list> reveals the header is included along with the following headers <utility> <string> <array> <deque> <forward_list>...

ctypes error AttributeError symbol not found, OS X 10.7.5

python,c++,ctypes

Your first problem is C++ name mangling. If you run nm on your .so file you will get something like this: nm test.so 0000000000000f40 T __Z3funv U _printf U dyld_stub_binder If you mark it as C style when compiled with C++: #ifdef __cplusplus extern "C" char fun() #else char fun(void)...

undefined reference to `vtable for implementation' error

c++,build,makefile

I think you just misspelled CFLAGS in CFLAGES=-c -Wall I'm guessing this is the case since g++ ../src/main.cpp -I ../include/ does not have the -c option...

pointer to pointer dynamic array in C++

c++,arrays,pointers

The valid range of indices of an array with N elements is [0, N-1]. Thus instead of for example this loop for (int i=1; i <= n; i++) ^^^^ ^^^^^^ you have to write for ( int i = 0; i < n; i++ ) As you used operator new...

3 X 3 magic square recursively

c++,algorithm,math,recursion

Basically, you are finding all permutations of the array using a recursive permutation algorithm. There are 4 things you need to change: First, start your loop from pos, not 0 Second, swap elements back after recursing (backtracking) Third, only test once you have generated each complete permutation (when pos =...

How can I convert an int to a string in C++11 without using to_string or stoi?

c++,string,c++11,gcc

Its not the fastest method but you can do this: #include <string> #include <sstream> #include <iostream> template<typename ValueType> std::string stringulate(ValueType v) { std::ostringstream oss; oss << v; return oss.str(); } int main() { std::cout << ("string value: " + stringulate(5.98)) << '\n'; } ...

Incorrect Polar - Cartesian Coordinate Conversions. What does -0 Mean?

c++,polar-coordinates,cartesian-coordinates

You are converting to cartesian the points which are in cartesian already. What you want is: std::cout << "Cartesian Coordinates:" << std::endl; std::cout << to_cartesian(to_polar(a)) << std::endl; std::cout << to_cartesian(to_polar(b)) << std::endl; //... Edit: using atan2 solves the NaN problem, (0, 0) is converted to (0, 0) which is fine....