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Create singleton using GCD's dispatch_once in Objective-C
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This is a perfectly acceptable and thread-safe way to create an instance of your class. It may not technically be a "singleton" (in that there can only ever be 1 of these objects), but as long as you only use the [Foo sharedFoo] method to access the objec...
How to change the CHARACTER SET (and COLLATION) throughout a database?
... table (Mysql). He set it up with Latin collation, when it should be UTF8, and now I have issues. Every record with Chinese and Japan character turn to ??? character.
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Cannot resolve the collation conflict between “SQL_Latin1_General_CP1_CI_AS” and “Latin1_General_CI_
...l
WHERE
object_id = OBJECT_ID('YourTableName')
Collations are needed and used when ordering and comparing strings. It's generally a good idea to have a single, unique collation used throughout your database - don't use different collations within a single table or database - you're only asking...
Multiple glibc libraries on a single host
...hared libraries) which all must match. One of the pieces is ld-linux.so.2, and it must match libc.so.6, or you'll see the errors you are seeing.
The absolute path to ld-linux.so.2 is hard-coded into the executable at link time, and can not be easily changed after the link is done.
To build an exec...
Change a Django form field to a hidden field
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If you have a custom template and view you may exclude the field and use {{ modelform.instance.field }} to get the value.
also you may prefer to use in the view:
form.fields['field_name'].widget = forms.HiddenInput()
but I'm not sure it will protect ...
Logical operators for boolean indexing in Pandas
I'm working with boolean index in Pandas.
The question is why the statement:
3 Answers
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How to Calculate Execution Time of a Code Snippet in C++
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You can use this function I wrote. You call GetTimeMs64(), and it returns the number of milliseconds elapsed since the unix epoch using the system clock - the just like time(NULL), except in milliseconds.
It works on both windows and linux; it is thread safe.
Note that the granular...
MySQL DROP all tables, ignoring foreign keys
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I found the generated set of drop statements useful, and recommend these tweaks:
Limit the generated drops to your database like this:
SELECT concat('DROP TABLE IF EXISTS `', table_name, '`;')
FROM information_schema.tables
WHERE table_schema = 'MyDatabaseName';
Note 1:...
error: ‘uint16_t’ does not name a type - c++1y / stl - 清泛IT社区，为创新赋能！
...ranted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or...
What is the canonical way to check for errors using the CUDA runtime API?
Looking through the answers and comments on CUDA questions, and in the CUDA tag wiki , I see it is often suggested that the return status of every API call should checked for errors. The API documentation contains functions like cudaGetLastError , cudaPeekAtLastError , and cudaGetErrorString , b...