大约有 41,000 项符合查询结果（耗时：0.0394秒） [XML]
What's a concise way to check that environment variables are set in a Unix shell script?
...(an empty string) is OK — not exactly what you want, but the alternative and older notation.
The second variant (using :?) requires DEST to be set and non-empty.
If you supply no message, the shell provides a default message.
The ${var?} construct is portable back to Version 7 UNIX and the Bourne ...
Splitting templated C++ classes into .hpp/.cpp files--is it possible?
...ors trying to compile a C++ template class which is split between a .hpp and .cpp file:
16 Answers
...
Is Javascript a Functional Programming Language?
Just because functions are first class objects, there are closures, and higher order functions, does Javascript deserve to be called a Functional Programming language? The main thing I think it lacks is Pure Functions, and it doesn't 'feel' like other functional languages, like lisp (although thats...
Using Version Control for Home Development?
Up till now I have been developing my personal and school
projects at home without using any form of revision control
software to handle my changes and whatnot.
...
Good Java graph algorithm library? [closed]
...eriences with any Java libraries for Graph algorithms. I've tried JGraph and found it ok, and there are a lot of different ones in google. Are there any that people are actually using successfully in production code or would recommend?
...
The identity used to sign the executable is no longer valid
...
It works for me as well. command + Q to exit XCode and restart. Cheers!
– Joey
Aug 30 '13 at 4:38
9
...
SQL query return data from multiple tables
...
Part 1 - Joins and Unions
This answer covers:
Part 1
Joining two or more tables using an inner join (See the wikipedia entry for additional info)
How to use a union query
Left and Right Outer Joins (this stackOverflow answer is excelle...
ETag vs Header Expires
...d around but haven't been able to figure out if I should use both an ETag and an Expires Header or one or the other.
8 ...
Fastest Way to Serve a File Using PHP
...receives a file path, identifies what it is, sets the appropriate headers, and serves it just like Apache would.
8 Answers
...
System.Timers.Timer vs System.Threading.Timer
I have been checking out some of the possible timers lately, and System.Threading.Timer and System.Timers.Timer are the ones that look needful to me (since they support thread pooling).
...