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Difference between malloc and calloc?
...tage of the OS's guarantee.
This means calloc memory can still be "clean" and lazily-allocated, and copy-on-write mapped to a system-wide shared physical page of zeros. (Assuming a system with virtual memory.)
Some compilers even can optimize malloc + memset(0) into calloc for you, but you should...
How to change the foreign key referential action? (behavior)
...a foreign key with column name fk_table2_id, with constraint name fk_name and table2 is referred table with key t2 (something like below in my diagram).
table1 [ fk_table2_id ] --> table2 [t2]
First step, DROP old CONSTRAINT: (reference)
ALTER TABLE `table1`
DROP FOREIGN KEY `fk_name...
Heroku Postgres - terminate hung query (idle in transaction)
I'm using Heroku with the Crane Postgres option and I was running a query on the database from my local machine when my local machine crashed. If I run
...
Can enums be subclassed to add new elements?
I want to take an existing enum and add more elements to it as follows:
15 Answers
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Check if pull needed in Git
...u} returns an abbreviated upstream ref (e.g. origin/master), which is then converted into space-separated fields by the piped sed command, e.g. origin master.
This string is fed into git ls-remote which returns the head commit of the remote branch. This command will communicate with the remote repos...
Web-scraping JavaScript page with Python
...e/'
r = Render(url)
result = r.frame.toHtml()
# This step is important.Converting QString to Ascii for lxml to process
# The following returns an lxml element tree
archive_links = html.fromstring(str(result.toAscii()))
print archive_links
# The following returns an array containing the URLs
ra...
Copy a stream to avoid “stream has already been operated upon or closed”
...low this pattern after a mapTo though using an IntStream. I found I had to convert it back to a Set<Integer> using collect(Collectors.toSet()) ... and do a couple of operations on that. I wanted max() and if a specific value was in set as two operations... filter(d -> d == -1).count() == 1;...
How can I extract a good quality JPEG image from a video file with ffmpeg?
...re precisely specify quality, subsampling and DCT method – e.g. GIMP) to convert the PNGs you want to JPEG.
It is possible to obtain slightly sharper images in JPEG format this way than is possible with -qmin 1 -q:v 1 and outputting as JPEG directly from ffmpeg.
...
Is there an equivalent for var_dump (PHP) in Javascript?
...ehaviors based on existance or
// absence of a var_name parameter. By converting 'undefined' to 'empty
// string', the length greater than zero test can be applied in all cases.
var_name = typeof var_name === 'undefined' ? '':var_name;
var out = '';
var v_name = '';
switch ...
from jquery $.ajax to angular $http
...ore concise (especially using .post() method)
AngularJS will take care of converting JS objects into JSON string and setting headers (those are customizable)
Callback functions are named success and error respectively (also please note parameters of each callback) - Deprecated in angular v1.5
use t...