How to translate these logical addresses into physical addresses?
memory-management,operating-system
In your model, the page table entry is address DIV page-size the offset is address MOD page-size I don't know if your addresses are hex or decimal. I will assume hex. For your first example--20 page table entry = 0 page offset = 20 Your page table entry 0 maps...
Host testing C program with hard coded memory addresses
c,linux,unit-testing,memory-management,functional-testing
You could check for e.g. the __linux__ macro and use conditional compilation. When on Linux use an array as base, and make it big enough to keep all the data needed in it. Something like e.g. #ifdef __linux__ int8_t array[1024]; # define MY_BASE_ADDRESS array #else # define MY_BASE_ADDRESS 0x00600000 #endif...
Does free() set errno?
POSIX doesn't define free to set errno (although POSIX doesn't currently forbid it, so an implementation might do so - refer to @ArjunShankar's answer for more details). But that's not really relevant to your concern. The way you're checking for errors is incorrect. You should check the return value of...
Memory Management (Allocating Pages/Frames to Logical Addresses)
memory,memory-management,operating-system,paging,virtual-memory
If you have a page size of 4096, then page number = address DIV 4096 page offset = address MOD 4096 Those two values uniquely identify the logical memory location. Two addresses can be in the same frame. If that were not the case, there would be no point in...
function to get 2d-arrays from stack and heap
c,arrays,memory,memory-management,malloc
If you try to do this in c or c++: int test[][]; you will get this error: error: declaration of 'test' as multidimensional array must have bounds for all dimensions except the first This is because test is not in fact a double ponter as you'd expect. But the compiler...
Strange error while adding a feature to my little game (0xC0000005)
c,memory-management,memory-leaks,heap-memory
First, you don't allocate your two-dimensional fields correctly. The "outer" field must hold int *, not just int: mineArray = calloc(10, sizeof(*mineArray)); for (i = 0; i < 10; i++) { mineArray[i] = calloc(10, sizeof(*mineArray[i])); } Another potential source of the segmentation fault is that Y might end up uninitialised...
Multipart form uploads + memory leaks in golang?
memory-management,memory-leaks,go
If the memory usage stagnates at a "maximum", I wouldn't really call that a memory leak. I would rather say the GC not being eager and being lazy. Or just don't want to physically free memory if it is frequently reallocated / needed. If it would be really a memory...
What is a “non-weak zeroing reference”
objective-c,cocoa,memory-management,nsnotificationcenter,osx-elcapitan
The answer for this lies deep within the objective-c runtime, and how __weak variables actually work. To explain, let's look a little bit at objc_weak.mm: id weak_read_no_lock(weak_table_t *weak_table, id *referrer_id) { ... if (! referent->ISA()->hasCustomRR()) { if (! referent->rootTryRetain()) { return nil; } } else { BOOL (*tryRetain)(objc_object *, SEL)...
Memory management in Contiki-OS
memory-management,heap-memory,contiki
All required memory is statically allocated during compilation/linkage. Its done by the PROCESS Macro[1], which allocates a structure containing the necessary information [2]. As for the events, they must allocate their own memory, too[3]. It is therefore not possible to run the same thread* or schedule the same event twice....
c++ dynamically declared array fails to work
c++,memory-management,new-operator,theory,heap-memory
save yourself loads of trouble, use a vector std::vector<double> data; data.reserve(SIZE_OF_ARRAY); // not totally required, but will speed up filling the values vector will give you better debug messages and you won't have to deal with memory yourself....
At what size should I malloc structs?
c,memory-management,struct,malloc
Good code gets re-used. Good code have few size limitations. Write good code. Use malloc() whenever there is anything more than trivial buffer sizes. Buffer size to write an int: The needed buffer size is at most sizeof(int)*CHAR_BIT/3 + 3. Use a fixed buffer. Buffer size to write a double...
Understanding Stack, Heap and Memory Management
c++,pointers,memory-management,stack,heap
The sequence is correct except one point: The delete []ip; removes the memory allocated on the heap to the ip pointer. The pointer that got passed through to myFun now points to nothing. The pointer doesn't point to 'nothing' (i.e. isn't set to nullptr or 0 after freeing the memory)....
Why I cannot use “fgets” to read a string to an element of my Struct?
c,pointers,memory-management,struct,fgets
Problems that I see: You are allocating the wrong amount of memory in the line: vet = (CLIENTES*)malloc(num*sizeof(int)); That should be: vet = malloc(num*sizeof(*vet)); See Do I cast the result of malloc?. The answers explain why you should not cast the return value of malloc. You are using fgets after...
Memory error in set resize
In your function you are taking the pointer into to_resize, then you realloc the memory, but you never set the new pointer back to the set->state_array[slot_i], so it is lost and you keep on using the old, already freed memory space and will point outside its bounds.
Retain cycle in Swift when Object A has Object B as a property and Object B has an array property that contains Object A?
ios,swift,memory-management,memory-leaks,retain-cycle
Generally speaking, with manual reference counting and automatic reference counting, reference ilands will leak. Reference cycle can be composed by more than just 2 objects. That said I encourage you to test some code in a playground since the example in your question has some syntax and language errors. The...
physical memory userspace/kernel split on Linux x86-64
memory,memory-management,linux-kernel,kvm
No. Almost any physical page frame can be mapped to a userspace virtual address or a kernel virtual address, or even both at the same time....
Operator Overloading without memory copies
c++,memory-management,operator-overloading
Before C++11, it depends on your compiler. The standards permit, but do not require, the compiler to eliminate (or elide) temporaries where the only way of detecting their existence is to track constructor and destructor calls. This is one case where that is permitted. In C++-11, look up rvalue references...
libXML: check if node is already unlinked and freed
memory-management,xpath,libxml2,vala
I'd suggest another way around to achieve the same. You can use a more specific xpath, so that in case there are nested elements having style attribute contains "display:none", only the outer-most elements gets selected : //*[contains(@style,'display:none')][not(ancestor::*[contains(@style,'display:none')])] ...
Memory analysis in Android: dominator_tree does not show all the instances of some objects
java,android,eclipse,memory-management,eclipse-memory-analyzer
Analyzing the results that are shown in the dominator_tree I have understand what happened: The dominator three show only the objects that have at least one path from GC root to them. It requires at least one reference for being shown in that diagram (It doesn't metter if is a...
When calling append on stringbuilder, are we adding strings to the heap?
c#,.net,memory-management,stringbuilder
are we not creating a string that is then used from the stringBuilder, to be appended and added to the internal character array - buffer ? In your correct example, yes. The string has to be first allocated and then added to the internal buffer. But imagine you have...
free() and mxFree() in MATLAB - freeing memory twice
matlab,memory-management,free,mex
The second loop does not index correctly for tau. You are defining indexing for tau as #define tau(a, b) tau[b+a*NrSensor] Let us walk through the second loop assuming NrSensor = 10 and len_zr = 5. For this case max value of loop variable i is 9 and max value of...
How will you free the memory allocated?
c,memory-management,malloc,free,dynamic-memory-allocation
It's simple. You can use this code to clean your only used variable. #include<stdio.h> #include<stdlib.h> #define MAXROW 3 #define MAXCOL 4 int main() { int **p, i, j; p = (int **) malloc(MAXROW * sizeof(int*)); free(p); return 0; } ...
URLClassLoader Memory Leak Java
java,memory-management,memory-leaks,urlclassloader
just add the dependency of class loader leak preventer in your build path. maven dependency for this is : <!-- For Classloader leak protection --> <dependency> <groupId>se.jiderhamn</groupId> <artifactId>classloader-leak-prevention</artifactId> <version>1.8.0</version> </dependency> ...
Fast memory allocation for real time data acquisition
The idea for solving this type of problems can be as follows: Separate the problem into 2 or more processes depending what you need to do with your data: Acquirer Analyzer (if you want to process data in real time) Writer Store data in a circular buffer in shared memory...
Is free() zeroing out memory?
c,gcc,memory-management,clang,free
There's no single definitive answer to your question. Firstly, the external behavior of a freed block will depend on whether it was released to the system or stored as a free block in the internal memory pool of the process or C runtime library. In modern OSes the memory "returned...
How are Strings created and stored in Java?
java,string,memory-management,immutability,hashcode
You have created String literals and String objects. String literals like s1 and s2 are stored in the String pool. as they are the same String they have the same reference. This is efficient. String objects created using the new keyword result in an object that is stored on the...
Weak and strong property implementation
For the first and second Q I refer to @rmaddy's comment and Christian's answer. So, actually i want to know, whether retain count decremented each time, when method that own variable finishes? First I want to be more precise: When you say "when method that own a variable finishes" you...
When do I need to free a Data Module created by the Application?
delphi,memory-management,datamodule
Answer to your question "When do I need to free a Data Module created by the Application?" is never. All data modules and/or forms created with Application.CreateForm method will be owned by Application and automatically handled. But as it seems, you issues are not related to automatic destruction process. Following...
Allocate 2D Array in C (not array of pointers) in Heap
c,arrays,pointers,memory-management,allocation
You don't need a special function. Just do it like this double (*A)[n][m] = malloc(sizeof *A); As of C99, here n and m can be any positive integer expressions you want. Such a thing is a pointer to a VLA, variable length array....
Is the memory assigned to a strong property released as soon as the property is set to nil?
objective-c,memory-management,automatic-ref-counting
Assigning nil to a strong variable does indicate that you no longer need the object the variable is referencing, and provided no other strong references to the object exist ARC will dispose of the object quickly, if not immediately. Your object is probably (see end) referenced by the autorelease pool,...
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...
C# apps using ram and cannot be cleared
Even though you are disposing of the objects, the memory will only actually be released when the Garbage Collector runs. You can force this to happen explicitly by running the following code: GC.Collect(); GC.WaitForPendingFinalizers(); However, it's not recommended to do this yourself as the Garbage Collector is intended to run...
Get VU of VSXu artiste with C++
c++,memory-management,dll,base-address,cheat-engine
The problem is I suppose because you are calling GetModuleHandle within your own process. The solution you can try is to use: GetModuleInformation, it will return base address in MODULEINFO as: lpBaseOfDll The load address of the module. To get process and module handle you can use sample code from...
Cannot free fileName char * after fclose
c,memory-management,malloc,free,realloc
You code is having issue in the below line strcat(*indexFileName, ".ind") the destination buffer at *indexFileName is having insufficient memory to hold the concatenated string. Hence it invokes undefined behaviour. From the man page of strcat() ... If dest (destination buffer) is not large enough, program behaviour is unpredictable; So,...
Are memory addresses in assembly language statically allocated at once?
c,assembly,memory-management,static,allocation
Try unsigned char (*ptrtomem)[8]; unsigned char (*ptr)[8]; /* ... */ ptrtomem = malloc(20000*8); ptr = ptrtomem-2500; /* use ptr[2500][] to ptr[24999][] */ /* when done */ free(ptrtomem); or use _alloca() (or alloca() depending on compiler) if you want to allocate off the stack....
malloc() - Does it use brk() or mmap()
c,memory-management,malloc,mmap,sbrk
If we change the program to see where the malloc'd memory is: #include <unistd.h> #include <stdio.h> #include <stdlib.h> void program_break_test() { printf("%10p\n", sbrk(0)); char *bl = malloc(1024 * 1024); printf("%10p\n", sbrk(0)); printf("malloc'd at: %10p\n", bl); free(bl); printf("%10p\n", sbrk(0)); } int main(int argc, char **argv) { program_break_test(); return 0; } It's...
Local const in recursion call
python,memory-management,recursion
I don't see any problems with a MAGIC_SPELLS constant. You can locale it near the magic function, so you know, the belong together: def magic_default(node): return magic(node.l) + magic(node.r) MAGIC_SPELLS = { 'AR_OP': ar_op_magic, 'PRE_OP': pre_op_magic, } def magic(node): if node: func = MAGIC_SPELLS.get(node.text, magic_default) return func(node) return "" ...
Allocating memory for pointers inside structures in functions
c,pointers,memory-management,struct
Code with comments: void f_alloc(ssm **a) { *a = malloc(sizeof(ssm)); // Need to allocate the structure and place in into the *a - i.e. hello in main (*a)->p = malloc(sizeof(int)); // Allocate memory for the integer pointer p (i.e. hello ->p; } EDIT I think this is what you are...
Why should I dimension my variables in VBA really?
Memory usage is only pleasant a side effect. The real reason I'd recommend using Option Explicit is that it allows the compiler to protect you from coding mistakes that compile and run, but don't do what you intend. Example 1: It keeps typos from turning into unexpected disasters. Dim variableNamedFoobar...
Free memory of byte[]
At the core, the problem is that you read from your file in one big chunk. If the file is very large (greater than 85,000 bytes to be precise), then your byte array will get stored in the LOH (large object heap). If you read up on the 'large object...
Valgrind says about “Invalid write” in fclose()
c++,memory-management,valgrind
It was my fault. I wrote that I use fmemopen() to open a stream, but this code wasn't running, and I get stream, produced earlier with open_memstream(). Although this stream was opened for writing, I can read from it. However valgrind reports about problem. I fixed my code, valgrind find...
Is there a difference between new List() and new List(0)
c#,.net,list,memory-management
Here is the actual source code (Some parts trimmed for brevity) static readonly T[] _emptyArray = new T[0]; public List() { _items = _emptyArray; } public List(int capacity) { if (capacity < 0) ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.capacity, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum); Contract.EndContractBlock(); if (capacity == 0) _items = _emptyArray; else _items = new T[capacity]; } As...
Garbage Collector doesn't immediately collect finished thread [duplicate]
java,multithreading,memory-management,garbage-collection
Could it be that you are asking the wrong question? What I mean: is the fact that garbage collection is not happening "immediately" a problem for you? I am pretty sure - when you start another such thread that needs a lot of memory, the GC will kick in all...
How can I ensure an emxArray is correctly allocated in generated C code?
matlab,memory-management,matlab-coder
It's good to see that you're making progress. Regarding the emxEnsureCapacity issue it is unfortunate and it is a bug. I'll take care of it to ensure we fix it in a forthcoming release. Meanwhile, there's a way of patching the generated source code. For config objects there's the 'PostCodeGenCommand'...
Convert IntPtr to char** in C#
c#,memory-management,types,type-conversion,dllimport
It should be something like: IntPtr di; int result = afc_read_directory(client, @"C:\", out di); if (di == IntPtr.Zero) { throw new Exception(); } IntPtr di2 = di; while (true) { IntPtr ptr = Marshal.ReadIntPtr(di2); if (ptr == IntPtr.Zero) { break; } string str = Marshal.PtrToStringAnsi(ptr); if (str == string.Empty) {...
Deleting a dynamically allocated 2D array [duplicate]
c++,memory-management,delete-operator
In reality, an array of pointers pointed to by a pointer is still an array of integral data types or numbers to hold the memory addresses. You should use delete[] for both. Also, yes, a new[] implies a delete[]. When you create an array of arrays, you're actually creating an...
When a view controller is dismissed, should it empty the memory?
ios,objective-c,memory-management,uiviewcontroller,automatic-ref-counting
If you are seeing this memory rise in Xcode and not when using instruments then the answer I have come up with is in this answer. You can read that whole answer, it's pretty in depth. But long story short, in Xcode you are seeing the amount of memory that...
C memory allocation and deallocation
Your for loops are wrong - you are iterating over one too many rows - change: for ( i = 0 ; i <= rows ; i ++ ) ^^^ to: for ( i = 0 ; i < rows ; i ++ ) ^^^ in both the malloc loop...
Unable to increase PHP Memory Limit
php,apache,memory,memory-management,out-of-memory
So it turns out the memory limit was being increased properly, just not being reflected in phpinfo(). The reason it was not reflecting in the phpinfo() echo, is because I was making the memory increase in the controller, and then echoing phpinfo() from the view, so the increase was not...
Proper memory cleanup with c_str() and const char *
c++,memory-management,stdstring,const-char
It's a pointer to memory allocated in std::string. When the std::string falls out of scope, the memory is released. Be sure not to hold onto the pointer after that!
How to free memory in C# that is allocated in C++
c#,c++,memory-management,dll,memory-leaks
You need to call the corresponding "free" method in the library you're using. Memory allocated via new is part of the C++ runtime, and calling FreeHGlobal won't work. You need to call (one way or the other) delete[] against the memory. If this is your own library then create a...
HTTPNetStreamInfo::_readStreamClientCallBack(__CFReadStream*, unsigned long) increases memory allocation
ios,memory,memory-management,xamarin,httpclient
Strange but yes, it is fixed in iOS8.3. NSURLCache was broken in iOS 8.x till iOS8.3. So it was not able to clear the cache. But as I have updated it to iOS8.3, it came down to 32KB block and consumes max 5-7MB.
Using mmap and madvise for huge pages
c,linux,memory-management,mmap,huge-pages
Both functions perform different operations, which may or may not matter in your context: madvise sets a flag for all the memory mappings corresponding to the region passed to it, telling the khugepaged kernel thread that it can consider said mappings for promotion to huge pages. That will only work...
C++ vector only save the last push_back value
c++,memory-management,vector,push-back
I invite you over to my house, giving you my address which you hastily note down on paper. You come over and see that my house has green walls. The next day, you copy the address into your phone's address book for safekeeping. A few months later, I repaint...
Most efficient way to clone a list into an existing list, minimizing memory reallocation?
c#,performance,list,memory-management,clone
if (destination.Capacity < source.Capacity) { /* Increase capacity in destination */ destination.Capacity = source.Capacity; } This is probably wrong... The source.Capacity could be bigger than necessary... And you are "copying" the elements already contained in destination to a "new" destination "buffer". This copy is unnecessary because then the elements of...
Is BitSet worth using?
BitSet will be less memory, using only one bit is far more efficient. The method overhead you are looking at is once no matter how many instances of your class you have, so its cost is amortized basically to 0 The advantage of a boolean over an array of booleans...
nodejs decrease v8 garbage collector memory usage
node.js,memory-management,garbage-collection,v8
You need to control the max memory size flags (all sizes are taken in MB). The recommended amounts for a "low memory device" are: node --max-executable-size=96 --max-old-space-size=128 --max-semi-space-size=1 app.js for 32-bit and/or Android and node --max-executable-size=192 --max-old-space-size=256 --max-semi-space-size=2 app.js for 64-bit non-android. These would limit the heap totals to 225mb...
Large memory pages and fragmentation
linux,memory-management,shared-memory,ppc
kernel will assign 64KiB for each request less than 64 KiB.
How to copy bytes from memory using pattern (YUYV packed to YUV420 planar)
c++,memory-management,video-processing,micro-optimization,pixelformat
Unfortunately, you can't do this with memcpy() tricks only. Modern processors have 64 bit registers and it is the optimal size for memory transfers. Modern compilers always try optimize memcpy() calls to do 64- (or 32- or even 128-) bit transfers at a time. But in your case you need...
Fortran memory allocation does not give an error, but the program is killed by OS at initialization
You are seeing the behavior of the memory allocation strategy linux uses. When you allocate memory but have not written to it, it is solely contained in virtual memory (note this may also be affected by the particular Fortran runtime library, but I'm not sure). This memory exists in your...
Getting many memory errors when try to run it for few days in my web crawler [on hold]
java,memory,memory-management,out-of-memory
I tried to allocate memory by changing eclipse.ini setting to 2048 MB of ram as it was answered in this topic but still get the same errors after 3 hours or less. I hate to repeat myself(*), but in eclipse.ini you set up the memory for Eclipse, which has...
Should I outsource allocation algorithm? (RAII)
struct Register { Register(): _trampoline_address(allocate()) {} Register(Register const& o): Register() // forward to default ctor { copy_data_from(o); } ~Register() { if (_trampoline_address) debug(VirtualFree(_trampoline_address, 0, MEM_RELEASE)); } Register& operator= (const Register& o) { if (this != std::addressof(o)) copy_data_from(o); return *this; } private: void copy_data_from(Register const& o) { Assert(_tranpoline_address); // ... }...
Sharing std::string across shared memory
string,c++11,memory-management
I wish to share a std::string across processes using shared memory. You cannot share non-POD types across process boundaries, especially types that may allocate memory internally. There is no guarantee that the other processes use the same version of the STL, if they use the STL at all. And...
Managing memory of Vector3's created to move gameObject
c#,memory-management,memory-leaks,unity3d
It creates a new Vector3 every FixedUpdate() (60 times per second, by default), even if user is not providing input. Vector3 created on a stack. And releasing once you left function. (No garbage collection) When you assign a variable movement to rigidbody.velocity, you are simply copying struct. (No garbage...
Temporary variable destroyed with overloaded + and += operator
c++,memory-management,operator-overloading
That's exactly how it should happen. It is probably more correct to say that it is not temporary b1 + b2 that gets destroyed, it is temporary Bcd(*this) += rhs inside your implementation of binary + that gets destroyed. Your implementation of + const Bcd& Bcd::operator +(const Bcd &rhs) const...
Using a data pointer with CUDA (and integrated memory)
The pointer has to be created (i.e. allocated) with cudaHostAlloc, even on integrated systems like Jetson. The reason for this is that the GPU requires (zero-copy) memory to be pinned, i.e. removed from the host demand-paging system. Ordinary allocations are subject to demand-paging, and may not be used as zero-copy...
How is garbage collection triggered in JavaScript?
javascript,memory-management,garbage-collection
There are many ways GCs can be triggered allocation-triggering: there is no more room in the allocation buffers/young generation/howeveritiscalled and a GC is required to free up objectsThis gets a bit more complicated in a mixed GC/manual allocation environment. malloc wrappers might need to trigger GCs too since javascript can...
Using Picasso to solve OutOfMemoryError
android,memory-management,out-of-memory,picasso
EDIT: well, you are using too much memory. remove those 3 lines of code : File imgFile = new File(data.get(position).get("path")); Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath()); imageView.setImageBitmap(myBitmap); simply, you are assigning too much space to these instances and your phone runs out of memory. Just use my response and consider logging the...
Android - effective performance and memory management
java,android,memory-management,memory-leaks
Some java virtual machines, when creating small objects of known size, which is not viewed outside of it scope, creates object in stack, rather than in heap. For example oracle JVM after 7th version doing so. So it is may be more efficient to create small constant size temporary arrays...
emptying an std::queue through a function that returns the front() and pops()
c++,memory-management,destructor
In case I get it right, the problem is the lack of a user-defined assignment operator for FileEntry. Your copy constructor takes care of the fact that each FileEntry has a new FolderInfo if the copied FileEntry has freeFolderInfo == true, whereas your assignment operator does not. If you assign...
Ideal memory usage amounts for iOS apps
ios,iphone,ipad,memory-management
You could get(a pretty nice) overview from this SO question. It won't show you low-medium values, but if you know the limit you can adjust below limit. If you are near the limits in some view - override didReceiveMemoryWarning and dispose resources accordingly. My advise is to test always on...
c - unsetenv() implementation, is it necessary to free memory?
In your case it is not necessary if you don't plan to set your environment variables very frequently leading to exhaust of your memory resources. But it would be great if you always deallocate resources after you are done with using them, be it file handles/memory/mutexs. By doing so you...
Why this memory management trick works?
It's not really a trick. It's the way that parts of Unity3D handle memory. In Unity3D you have objects that are handled by Mono and will be garbage collected, and objects that are handled by Unity, that will not be garbage collected. Strings, ints etc are cleaned up by Mono...
Explanation of why allocating a large array results in segmentation fault in C [duplicate]
It depends where you allocated the array. If it's inside a function, then the variable is allocated on the stack, and by default, (I assume you're running linux) the stack size is 8Mb. You can find it out using ulimit -s and also modify this value, for instance ulimit -s...
Objective-C memory leak when returning NSString
ios,objective-c,iphone,memory-management,memory-leaks
What you posted is OK. The only rule at this point is that methods contain "create" or "alloc" will return an object that needs to be explicitly released. In your case that is the string returned in the readString method. Since the object will be returned you need to retain...
Simple explanation about loading files into memory
vb.net,visual-studio-2010,memory-management
When they refer to reading something "into memory" it is simply a way of saying that you are reading it and storing it in a variable (which stores it in memory). Use ReadAllLines to read the entire file into memory: Dim readText() As String = File.ReadAllLines(path) See File.ReadAllLines Method (String)...
DataTable does not release memory
c#,memory,memory-management,datatable
Your main problem is the behavior of the Garbage Collector is different depending on if you are debugging or in release mode without a debugger present. When in a debug build or a release build with a debugger present all objects have their lifetimes extended to the entire lifetime of...
Function in C extension randomly stops python program execution
python,c,memory-management,random,python-c-extension
I figured out how to avoid the problem: The function ptrvectorInt, that shall allocate the memory for the output array, did not work properly. I replaced it by int **ptrvectorInt(long dim1) { int **v; if (!(v = malloc(dim1 * sizeof(int*)))) { PyErr_SetString(PyExc_MemoryError, "In **ptrvectorInt. Allocation of memory for integer array...
Invalid free() / delete / delete[] / realloc(), 4 bytes inside a block of size 16 alloc'd [closed]
c++,memory-management,vector,valgrind
Solution: Thanks to everyone who suggestion I put in asserts (god, grad school has turned me into a TERRIBLE programmer), which led me to catch the problem: one of the words in the dictionary was "MP3" which wasn't entirely alphanumeric. I didn't realize that that kind of error would wait...
When do autorelease pools drain?
ios,objective-c,memory-management
The documentation is not specific on when the "main" autorelease pool drains, but generally you can assume it is drained at the end of the application's main event loop. Here's what happens with regards to autorelease pools: An autorelease pool is created when an application starts. When another pool is...
Java how to limit number of threads acting on method
java,multithreading,memory-management
You can use the Executor.newFixedThreadPool idiom, internally to your execution logic. Full example below: public class Main { public static void main(String[] args) throws Exception { Main m = new Main(); // simulating a window of time where your method is invoked continuously for (int i = 0; i <...
Retain cycle with parent-child construction
ios,objective-c,memory-management,memory-leaks,retaincount
The word you are looking for is "retain cycle". The simplest retain cycle would be an object having a strong reference to itself. Very rare because it is rather pointless. The most common case is A having a strong reference to B and B having a strong reference to A....
How to get current memory page size in C#
Try Environment.SystemPageSize: Gets the number of bytes in the operating system's memory page. Requires .NET >= 4.0 In the remarks it is even written that: In Windows, this value is the dwPageSize member in the SYSTEM_INFO structure. ...
calloc created array is not acting as expected
c++,pointers,memory-management,calloc
Probably your debugger doesn't know how big buffer_buffer is, since that variable is simply declared as being a pointer to an int. (That's not correctly typed; buffer_buffer is used to hold values of buffer which is an int*, so buffer_buffer must be an array of int*, which means that you...
xCode 6.3.2 Crash [UIViewController .cxx_destruct]
objective-c,xcode,core-data,memory-management
// Code which caused [UIViewController .cxx_destruct] Article *article = [Article new]; // Fixed with this NSManagedObject *article = [NSEntityDescription insertNewObjectForEntityForName:@"Article" inManagedObjectContext:context]; ...
Memory address in linked list C++
c++,memory-management,linked-list
You're printing: "Current Add:\t" << &cur << endl << This is the address of the variable: struct node *cur; The address of that pointer (not the address it points to!) will of course not change. You probably intended to write: "Current Add:\t" << cur << endl << ...
memory content not erased after deleting my pointer (on a simple example) [duplicate]
c++,pointers,memory-management
It may or may not print the same value after delete operation. So simply what you are observing is an undefined behavior.
Modern C++ idiom for allocating / deallocating an I/O buffer
Basically, you have two main C++-way choices: std::vector std::unique_ptr I'd prefer the second, since you don't need all the automatic resizing stuff in std::vector, and you don't need a container - you need just a buffer. std::unique_ptr has a specialization for dynamic arrays: std::unique_ptr<int[]> will call delete [] in it's...
S_realloc: How to increase the length of a *numeric* vector? (first argument not char*)
That should be as easy as adding a cast foo = S_realloc((char*) p, n1, n2, n3); where p is your double *p. There is also an alternate form TYPE* Calloc(size_t N, TYPE) TYPE* Realloc(ANY *P, size_t N, TYPE) void Free(ANY *P) per Section 6.1.2 User-controlled Memory of Writing R Extensions....
QEvent ownership
event = &stackevent; //valid ?? Usually that's not safe, but in this case it's valid, because the function notify won't return, untill the event is handled (or not) by someone (it means that stackevent will be "alive" during this operation). delete heapevent; //valid? or lost ownership? Yap, that's valid...
Bitshifting on little-endian and big-endian [duplicate]
c++,memory,memory-management,binary
Yes. Endianness only affects how bytes are stored in memory. The value of 0x10203040 is always 270544960 regardless of whether it's the first or last byte in memory that is the 0x10. To gratuitously borrow images from the Wikipedia article on Endianness, regardless of which of these layouts our system...
munmap_chunck(): invalid pointer in c
c,pointers,memory-management,global-variables
This is a common problem which occurs when you provide free a pointer which doesn't point to the start of an allocated memory block. For example, the code int* something = malloc(sizeof(int)); // Allocate space for 1 int ... free(something); will work fine as you are providing free with the...
Using parse.com and having allocation memory issue
android,memory,memory-management,parse.com,allocation
If you are using parse.com and getting the Images from database and converting it to bitmaps it will crash your app.. what you should do is, get the image of the URL from parse.com there is method called.. ParseFile.getUrl(); For that implement the Picasso library, which is perfect solution for...
Is there a better way to do this than writing a wrapper allocator that stores a reference to a stateful allocator object?
c++,memory-management,lambda,allocator,std-function
The standard "Allocator" concept would have been better named "AllocatorReference." Each object either refers to a global instance (stateless) or to an external object (stateful). Either way, the allocator instance within an allocator-aware container does not own a memory pool by itself. It's only a proxy. Note that allocator objects...
Core Data One-To-Many Relationship Memory Usage
ios,core-data,memory-management,one-to-many
There are NUMEROUS disadvantages to not specifying an inverse. You will have poorer performance, Core Data will need to work harder and you risk integrity issues. Always, always, always have an inverse relationship. Even if you will never use it, Core Data will. You will not have a memory issue...
How to have my program stops if its memory consumption exceeds a limit ?
A simple mechanism for controlling a process's resource limits is provided by setrlimit. But that doesn't isolate the process (as you should for untrusted third-party code), it only puts some restrictions on it. To properly isolate a process from the rest of the system, you should either use a VM,...
Efficiently transferring elements between arrays
javascript,arrays,optimization,memory-management,data-structures
splice is pretty harmful for performance in a loop. But you don't seem to need mutations on the input arrays anyway - you are creating new ones and overwrite the previous values. Just do function doTransfers() { var A_pending = []; var B2_pending = []; for (var i = 0;...
Where C++ calls destructors?
c++,class,memory-management,destructor
At which point does C++ call destructor of each m1, m2 and lst? The destructors are called at the end of the scope, in the reverse order of the objects definitions. In your case, func1() is first called, which defines lst, then calls fillList(), which defines m1 and m2....
Necessary to delete dynamic struct contents, and then the struct itself?
The issue actually stems from here: bread->name = "bread"; After allocating a new array for name, you are assigning that pointer to a completely different value - one that happens to live in read-only memory. Hence the error when you delete it: you're trying to delete [] an array that...