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How do pointer to pointers work in C?
... *p = 5;
return 1;//success
}
int get1024HeapMemory(int **p)
{
*p = malloc(1024);
if(*p == 0)
return -1;//error
else
return 0;//success
}
And you call it like this:
int x;
getValueOf5(&x);//I want to fill the int varaible, so I pass it's address in
//At this point x holds 5...
What is external linkage and internal linkage?
...tructed due to issues with global construction order and can't dynamically allocate it using new while more in-depth initialization schemes may be beyond what is necessary for the object in question; by implication, this is mainly an issue on embedded systems that use C++).
– J...
How to make an array of arrays in Java
...
@Filip it is fixed to 5. Setting the next level pre-allocates them but this can be changed so setting it might not be useful.
– Peter Lawrey
Aug 8 '13 at 12:56
...
What are the differences between poll and select?
...s, and see if it ever gets fixed.
With poll(), however, the user must allocate an array of pollfd
structures, and pass the number of entries in this array, so there's
no fundamental limit. As Casper notes, fewer systems have poll() than
select, so the latter is more portable. Also, with...
throwing exceptions out of a destructor
...mory for Object go? Where does the memory the object owned go? Is it still allocated (ostensibly because the destructor failed)? Consider also the object was in stack space, so its obviously gone regardless.
Then consider this case
class Object
{
Object2 obj2;
Object3* obj3;
virtual ~Obj...
Why are Objective-C delegates usually given the property assign instead of retain?
...wner
If B had retained A, A wouldn't be released, as B owns A, thus A's dealloc would never get called, causing both A and B to leak.
You shouldn't worry about A going away because it owns B and thus gets rid of it in dealloc.
...
Create an index on a huge MySQL production table without table locking
...able users add index ddopsonfu (last_name, email, first_name, confirmation_token, current_sign_in_ip);'
echo "Index Update - FINISH"
sleep 0.05
kill $PID
time mysql -uroot website_development -e 'drop index ddopsonfu on users;'
My Server (InnoDB):
Server version: 5.5.25a Source distribution
Out...
How to correctly implement custom iterators and const_iterators?
...
You need to edit your answer. Assuming m_data was allocated with m_size elements you get Undefined Behavior: m_data[m_size] is UB. You can simply fix it by replacing it with m_data+m_size. For reverse iterators, both m_data[-1] and m_data-1 are incorrect (UB). To fix reverse...
What's the difference between SoftReference and WeakReference in Java?
...object is phantomly referenced after it has been finalized, but before its allocated memory has been reclaimed.
Source
Analogy: Assume a JVM is a kingdom, Object is a king of the kingdom, and GC is an attacker of the kingdom who tries to kill the king(object).
When King is Strong, GC can not k...
Is Fortran easier to optimize than C for heavy calculations?
...ers will most likely return that struct in sret form with the caller stack allocating space, passing a pointer to the callee that fills it in. That is several times slower than returning multiple values in registers as a Fortran compiler would. Note that C99 fixed this in the special case of complex...