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Abort makefile if variable not set
...ning an auxiliary function for that:
# Check that given variables are set and all have non-empty values,
# die with an error otherwise.
#
# Params:
# 1. Variable name(s) to test.
# 2. (optional) Error message to print.
check_defined = \
$(strip $(foreach 1,$1, \
$(call __check_defin...
Preferred order of writing latitude & longitude tuples in GIS services
When dealing with GIS source code you often need to write latitude and longitude coordinate tuples.
9 Answers
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Why so red? IntelliJ seems to think every declaration/method cannot be found/resolved
I just installed and re-installed IntelliJ. Every Java file is coming up RED. I checked the JDK; it is at 1.6.##. The maven clean install build worked just fine.
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How to filter SQL results in a has-many-through relation
Assuming I have the tables student , club , and student_club :
13 Answers
13
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Convert a Git folder to a submodule retrospectively?
Quite often it is the case that you're writing a project of some kind, and after a while it becomes clear that some component of the project is actually useful as a standalone component (a library, perhaps). If you've had that idea from early on, then there's a fair chance that most of that code is ...
What are “named tuples” in Python?
...tances can be referenced using object-like variable dereferencing or the standard tuple syntax. They can be used similarly to struct or other common record types, except that they are immutable. They were added in Python 2.6 and Python 3.0, although there is a recipe for implementation in Python 2...
The SQL OVER() clause - when and why is it useful?
I read about that clause and I don't understand why I need it.
What does the function Over do? What does Partitioning By do?
Why can't I make a query with writing Group By SalesOrderID ?
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Is multiplication and division using shift operators in C actually faster?
Multiplication and division can be achieved using bit operators, for example
19 Answers
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How do I check if a number evaluates to infinity?
...lert(x === Infinity); displays "true". (Admittedly that's an obscure case, and anyone who decides to redefine Infinity, NaN etc should expect odd things to happen.)
– LukeH
Jan 18 '11 at 13:49
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What does (x ^ 0x1) != 0 mean?
...expression is false if x == 1.
So the test is the same as:
if (x != 1)
and is therefore (arguably) unnecessarily obfuscated.
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