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When should we use mutex and when should we use semaphore
...have to carefully track who currently has responsibility for it, much like allocated memory).
So, if you have a number of instances of a resource (say three tape drives), you could use a semaphore with a count of 3. Note that this doesn't tell you which of those tape drives you have, just that you ...
Why are preprocessor macros evil and what are the alternatives?
...to wrap a function with macros to pass on file/line information:
#define malloc(x) my_debug_malloc(x, __FILE__, __LINE__)
#define free(x) my_debug_free(x, __FILE__, __LINE__)
Now we can use my_debug_malloc as the regular malloc in the code, but it has extra arguments, so when it comes to the end...
Regular cast vs. static_cast vs. dynamic_cast [duplicate]
... // 4 bytes
Since this results in a 4-byte pointer pointing to 1 byte of allocated memory, writing to this pointer will either cause a run-time error or will overwrite some adjacent memory.
*p = 5; // run-time error: stack corruption
In contrast to the C-style cast, the static cast will allow t...
Is there any way to put malicious code into a regular expression?
...ime–space trade‐off.
With a DFA, you spend more time building it (and allocating more states), whereas with an NFA you spend more time executing it, since it can be multiple states at the same time, and backtracking can eat your lunch — and your CPU.
Denial‐of‐Service Solutions
Probably...
Can dplyr package be used for conditional mutating?
...the 2nd iteration forward (which might affect timing since DT$g is already allocated?), the result also propagates back to ans1 and therefore might (if R's optimizer deems it necessary? Not sure on this...) avoid another copy that DPLYR_fun and BASE_fun need to make?
– Ken Will...
performSelector may cause a leak because its selector is unknown
...memory management (e.g., that your methods do not return objects that they allocate).
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What is the recommended approach towards multi-tenant databases in MongoDB?
...decided not to have a database per
customer because of the way MongoDB
allocates its data files. Each
database uses it’s own set of files:
The first file for a database is
dbname.0, then dbname.1, etc. dbname.0
will be 64MB, dbname.1 128MB, etc., up
to 2GB. Once the fil...
Design patterns or best practices for shell scripts [closed]
...do object oriented programming, unless you build a quite complex system of allocation of objects (I thought about that. it's feasible, but insane).
In practice, you can however do "Singleton oriented programming": you have one instance of each object, and only one.
What I do is: i define an object ...
Does const mean thread-safe in C++11?
...too artificial, you could mentally replace int by a very large dynamically allocated integer which is inherently non thread-safe and for which multiplications are extremely costly.]
The member-function area is no longer thread-safe, it is doing writes now and is not internally synchronized. Is it a ...
Uses for Optional
...) { return Optional.ofNullable(parent); }. This looks expensive because it allocates an Optional every time! But if the caller unpacks it immediately, the object is extremely short-lived and is never promoted out of eden space. It might possibly even be eliminated by the JIT's escape analysis. The b...