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Are there disadvantages to using a generic varchar(255) for all text-based fields?
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It's good practice to allocate only a little over what you need. Phone numbers would never go this large.
One reason is that unless you validate against large entries, no doubt someone will use all there is. Then you might run out of space in...
What is an existential type?
..., because no identifier has been bound to it. (The ? wildcard is a special token, not an identifier that "captures" a type.) t.value has effectively become opaque; perhaps the only thing you can still do with it is type-cast it to Object.
Summary:
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Should 'using' directives be inside or outside the namespace?
...ler errors. However, it is unclear which version of the Guid type is being allocated. If the using directive is moved inside of the namespace, as shown below, a compiler error will occur:
namespace Microsoft.Sample
{
using Guid = System.Guid;
public class Guid
{
public Guid(stri...
How do you know when to use fold-left and when to use fold-right?
... // third stack frame
// (I don't remember if the JVM allocates space
// on the stack for the third frame as well)
while List(1,2,3).foldLeft(0)(_ + _) would reduce to:
(((0 + 1) + 2) + 3)
which can be iteratively computed, as done in the implementation of List.
In a str...
In a storyboard, how do I make a custom cell for use with multiple controllers?
...k at the class of the cell, as defined in the cell's nib. Call [[CellClass alloc] initWithCoder:].
The -initWithCoder: method goes through and adds subviews and sets properties that were defined in the nib. (IBOutlets probably get hooked up here as well, though I haven't tested that; it may happen i...
Markup XML解析库下载（Markup.h 和 Markup.cpp） - 源码下载 - 清泛网 - 专注C/C++及内核技术
...L ftell
#define MCD_INTFILEOFFSET long
#endif
struct FilePos;
struct TokenPos;
struct NodePos;
struct PathPos;
struct SavedPosMapArray;
struct ElemPosTree;
class CMarkup
{
public:
CMarkup() { x_InitMarkup(); SetDoc( NULL ); };
CMarkup( MCD_CSTR szDoc ) { x_InitMarkup(); SetDoc( sz...
Use numpy array in shared memory for multiprocessing
... size of the Array. Think of it as a shared block of memory that had to be allocated before child processes are started. You don't need to use all the memory e.g., you could pass count to numpy.frombuffer(). You could try to do it on a lower level using mmap or something like posix_ipc directly to i...
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 ...
Understanding Canvas and Surface concepts
...seen.
A Bitmap is just an interface to some pixel data. The pixels may be allocated by Bitmap itself when you are directly creating one, or it may be pointing to pixels it doesn't own such as what internally happens to hook a Canvas up to a Surface for drawing. (A Bitmap is created and pointed to ...
Is pass-by-value a reasonable default in C++11?
... especially around memory management (in the event that the object is heap-allocated)
4 Answers
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