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lua和c/c++互相调用实例分析 - C/C++ - 清泛网 - 专注C/C++及内核技术
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void (lua_pushinteger) (lua_State *L, lua_Integer n);
void (lua_pushlstring) (lua_State *L, const char *s, size_t l);
void (lua_pushstring) (lua_State *L, const char *s);
void (lua_pushboolean) (lua_State *L, int b);
void (lua_pushcclosure) (lua_State *L, lua_CFunction fn, int n);
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Why can Java Collections not directly store Primitives types?
...tion of primitives. Even in the few cases where I might have wanted to the extra time and space costs of using the reference objects has been negligible. In particular I find that many people think they want Map<int,T>, forgetting that an array will do that trick very nicely.
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What is “overhead”?
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Overhead typically reffers to the amount of extra resources (memory, processor, time, etc.) that different programming algorithms take.
For example, the overhead of inserting into a balanced Binary Tree could be much larger than the same insert into a simple Linked Li...
How can I eliminate slow resolving/loading of localhost/virtualhost (a 2-3 second lag) on Mac OS X L
...lower! For now, I've split things up into two hosts entries (with the same IP address) and it seems to be going fine.
– Alex Ghiculescu
Apr 15 '13 at 6:46
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How to remove first 10 characters from a string?
How to ignore the first 10 characters of a string?
12 Answers
12
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psql: FATAL: Peer authentication failed for user “dev”
...0.0.1 -d db_name
where
-U is the database user name
-h is the hostname/IP of the local server, thus avoiding Unix domain sockets
-d is the database name to connect to
This is then evaluated as a "network" connection by Postgresql rather than a Unix domain socket connection, thus not evaluated ...
Are there disadvantages to using a generic varchar(255) for all text-based fields?
... (If you're wondering, it's this way because Ruby on Rails migrations map String fields to VARCHAR(255) by default and I never bothered to override it).
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Equals(=) vs. LIKE
... these operators!
= is a comparison operator that operates on numbers and strings. When comparing strings, the comparison operator compares whole strings.
LIKE is a string operator that compares character by character.
To complicate matters, both operators use a collation which can have important...
Group query results by month and year in postgresql
...ht make sense to use date_trunc, but in some cases having a formatted date string is preferable, and if you're using a performant data warehouse the additional computation might not be a deal breaker. For example, if you are running a quick analytics report using redshift, and it usually takes 3 sec...
Please explain the exec() function and its family
... family have different behaviours:
l : arguments are passed as a list of strings to the main()
v : arguments are passed as an array of strings to the main()
p : path/s to search for the new running program
e : the environment can be specified by the caller
You can mix them, therefore you have:
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