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What's the difference between Perl's backticks, system, and exec?
...t, and don't want to wait for it to return. system is really just
sub my_system {
die "could not fork\n" unless defined(my $pid = fork);
return waitpid $pid, 0 if $pid; #parent waits for child
exec @_; #replace child with new process
}
You may also want to read the waitpid and perli...
What are the differences between Deferred, Promise and Future in JavaScript?
...es from [Functional Reactive Programming|haskell.org/haskellwiki/Functional_Reactive_Programming], which is a technique for flattening callbacks."
– fncomp
Feb 11 '13 at 5:32
2
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Integrate ZXing in Android Studio
...tIntegrator(this);
integrator.setDesiredBarcodeFormats(IntentIntegrator.ONE_D_CODE_TYPES);
integrator.setPrompt("Scan a barcode");
integrator.setCameraId(0); // Use a specific camera of the device
integrator.setBeepEnabled(false);
integrator.setBarcodeImageEnabled(true);
integrator.initiateScan();
...
Is it possible to roll back CREATE TABLE and ALTER TABLE statements in major SQL databases?
...
http://wiki.postgresql.org/wiki/Transactional_DDL_in_PostgreSQL:_A_Competitive_Analysis provides an overview of this issue from PostgreSQL's perspective.
Is DDL transactional according to this document?
PostgreSQL - yes
MySQL - no; DDL causes an implicit commit
Oracl...
Difference between Destroy and Delete
...ary key, and no callbacks are executed.
To enforce the object's before_destroy and after_destroy callbacks or any :dependent association options, use #destroy.
ActiveRecord::Persistence.destroy
Deletes the record in the database and freezes this instance to reflect that no changes should b...
ActiveRecord: size vs count
...e a new record without going through the relation, i.e. Comment.create(post_id: post.id), your post.comments.size will not be up to date, while post.comments.count will. So just be careful.
– mrbrdo
Mar 31 '13 at 19:52
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VC MFC工具栏(CToolBar)控件 - C/C++ - 清泛网 - 专注C/C++及内核技术
...钮吧，首先在对应话类里添加一个按钮类成员变量CButton m_Button;
然后在对话框编辑区里给对话框添加一个按钮控件（单击这个按钮创建按钮控件）,然后添加这个按钮控件单击消息处理函数，并在函数添加以下语句：
RECT ButtonR...
What is a semaphore?
...interestingly it has already been used: albahari.com/threading/part2.aspx#_Semaphore
– Igor Brejc
Mar 27 '15 at 8:50
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TCP vs UDP on video stream
...occer-fans and the internet itself is against me so I figure it's my loss ^_^
– Alxandr
May 31 '11 at 12:46
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show 2 more comments
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Percentage Height HTML 5/CSS
... edited Feb 18 '17 at 5:54
Web_Designer
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answered Oct 25 '09 at 21:15
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