App-Cheats
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files during compilation.
-L - Specify additional directories
to be searched for libraries
during linking.
#############################################################
## C,CPP Asynchronous (Threads)
#############################################################
# Run a process/function async (thread)
# Add this to makefile
LIB += -pthread
#
# Add library
#include <pthread.h>
#
# Declare threads
pthread_t threads[1];
#
# Create threads and get return code
# Sending pattern as parameter (only one allowed)
# Thread ID is first parameter
int rc;
rc = pthread_create(&thread, NULL, send_thread, (void *) pattern );
pattern->tid = thread; // Save thread ID so we can later kill it (if needed)
if(rc) return; // Error
#
# Check return value
if(rc) sendlog("ERROR: return code from pthread_create() is %d", rc);
#
# Function is declared like this:
void *send_thread (void * args){
COMMAND_PATTERN* pattern = (COMMAND_PATTERN*) args; // Can use pattern normally
...
}
#
# Make sure to end the function with this:
# (it will exit the thread. don't use in main otherwise will get defunct/zombie process)
pthread_exit(NULL);
# Determine version and library used for threads
# NPTL - Native POSIX Threads Library # Threads share PID
# LinuxThreads # May be different PIDs (plus may other differences)
getconf GNU_LIBPTHREAD_VERSION # NPTL 2.7
#############################################################
## C,CPP - Debug
#############################################################
# Sleepy poll (debug,ddd,gdb,break)
std::stringstream ss;
ss << data;
return ss.str();
}
#############################################################
## C,CPP - Threads
#############################################################
# Get the current thread's name (like thread ID, tid)
QThread::currentThread()->objectName()
#############################################################
## C,CPP - Timer
#############################################################
# Timer in Cpp
#
#include <ctime>
# Check if cgroups is enabled (ubuntu)
cat /proc/cmdline
# Check if using cgroups v1:
ls /sys/fs/cgroup
blkio cpuacct cpuset freezer memory net_cls,net_prio perf_event rdma unified
cpu cpu,cpuacct devices hugetlb net_cls net_prio pids systemd
# Check if using cgroups v2:
ls /sys/fs/cgroup
cgroup.controllers cgroup.max.descendants cgroup.stat cgroup.threads system.slice
cgroup.max.depth cgroup.procs cgroup.subtree_control init.scope user.slice
#############################################################
## Docker Build
#############################################################
# Build a docker image based on the Dockerfile
cd ~/tmp/learning_docker/02-*
docker build .
perl -le '$i=@a=\(qw/a b c/); print ${$a[$n=rand $i--]} and $a[$n]=$a[$i] for @a'
# Get random element of an array in perl.
my @a = 4..10;
print $a [rand ~~@a]
# Print the elements of an array segregated (in parenthesis)
perl -le '@a=qw/this is an array/; local $"=")("; print "(@a)"'
# Split a list into so many parts
# Purpose: Prepare for thread usage.
perl -le '$M=10; $T=3; $from=1; while($to < $M){ $to=$from+(($M-$from+1)/$T--)-1; $to=int($to)+1 if $to != int($to); print "$from -> $to"; $from=$to+1 }'
# Take 3 elements or an array/list at a time
perl -le '@a=0..30; push @b,[splice @a,0,3] while @a; print "@$_" for @b'
# Localized an array slice for a scope
perl -le 'sub pr{print "[@a]"} @a=qw/aa bb cc/; pr; {local @a[0,2]=qw/dd ff/; pr} pr'
# Perl sample array function.
+ sub get_max_length {
# View optimizations done on a pattern.
perl -Mre=optimization -Mojo -E 'say r optimization qr/^abc/'
# A way to check if using a regular expression.
perl -Mre=is_regexp -E 'say is_regexp qr{}'
1
perl -Mre=is_regexp -E 'say is_regexp 123'
#############################################################
## Perl Modules - threads
#############################################################
# Error: This Perl not built to support threads
# Check if perl binary supports threads.
perl -V:useithreads
perl -MConfig -E 'say $Config{useithreads}'
# Simple thread example in perl
# Threads start running already with threads->create()
perl -Mthreads -le '@t=map threads->create(sub{print "Im #$_"}), 1..10; $_->join for @t'
# Simple thread example in perl
# Find the summation of 1 through 10
# Uses a shared variable between threads
perl -Mthreads -Mthreads::shared -le '$sum=0; share($sum); @t=map threads->create(sub{$sum += $_}), 1..10; print $_->join for @t; print "sum: $sum"'
# Aliases for threads->create.
perl -lMthreads -le '@t=map threads->new(sub{print $_}), 1..3; $_->join for @t'
perl -lMthreads -le '@t=map async(sub{print $_}), 1..3; $_->join for @t'
perl -lMthreads -le '@t=map threads->new(sub{print $_}), 1..3; $_->join for @t'
# If using a coderef, you must use threads->create.
perl -lMthreads -le '$sub = sub{ print "123" }; @t=map threads->new( $sub ), 1..3; $_->join for @t'
# If using a coderef, you must use threads->create (with arguments).
perl -lMthreads -le '$sub = sub{ print "@_" }; @t=map threads->new( $sub, $_ ), 1..3; $_->join for @t'
# Shared and non shared variables example
perl -lMthreads -Mthreads::shared -le '$a=$b=1; share($a); async(sub{$a++; $b++})->join; print "a=$a, b=$b"'
# Thread pitfall. $a can be either 2 or 3 (race condition)
perl -lMthreads -Mthreads::shared -le '$a=1; share($a); $_->join for map async(sub{my $foo=$a; $a=$foo+1}), 1..2; print "a=$a"'
# Allow only one thread to touch a variable at a time
# This will cause a "deadlock" where one thread requires a reourses
# locked by another thread and vice versa
perl -Mthreads -Mthreads::shared -le 'share $a; share $b; push @t, async(sub{lock $a; sleep 20; lock $b}); push @t, async(sub{lock $b; sleep 20; lock $a}); $_->join for @t'
#
# Alternate syntax 1
perl -Mthreads -le 'my $a :shared; my $b :shared; push @t, async(sub{lock $a; sleep 20; lock $b}); push @t, async(sub{lock $b; sleep 20; lock $a}); $_->join for @t'
#
# Alternate syntax 2
perl -Mthreads -le 'my $a :shared; my $b :shared; push @t, threads->create(sub{lock $a; sleep 20; lock $b}); push @t, threads->create(sub{lock $b; sleep 20; lock $a}); $_->join for @t'
# Thread safe queues. Passing data around
perl -Mthreads -MThread::Queue -le 'my $q=Thread::Queue->new; $t=async(sub{ print "Popped $d off the queue" while $d=$q->dequeue }); $q->enqueue(12); $q->enqueue(qw/A B C/); sleep 1; $q->enqueue(undef); $t->join'
# Thread safe queues. Passing complex data around
perl -Mthreads -MThread::Queue -le 'my $q=Thread::Queue->new; $t=async(sub{ print "Popped @$d off the queue" while $d=$q->dequeue }); $q->enqueue([1..3]); $q->enqueue([qw/A B C/]); sleep 1; $q->enqueue(undef); $t->join'
# Compute pi using parallel threading
time perl -Mthreads -Mthreads::shared -le 'share $sum; $M=100_000_000; $T=6; $h=1/$M; sub sum { my $s; my($from,$to)=@_; for($from..$to){ my $x=$h*($_-0.5); $s += 4/(1+$x**2)}; $s } sub split_by { my($max,$by)=@_; my $from=1; my @l; while($to<$max){ ...
#############################################################
## Perl Modules - CAM::PDF
#############################################################
# Example getting title fields from a pdf.
use CAM::PDF;
use e;
my $infile = shift or die "\nSyntax: perl fill:pdf.pl my.pdf\n";
# PadWalker::Eval ideas.
sub eval ($string, $scope_level=0)
#############################################################
## Perl Modules - Parallel::ForkManager
#############################################################
# Simple exmplae of parallel processing
# (Perl Modules - Parallel::ForkManager)
# About 3 times slower than using threads!!!
perl -MParallel::ForkManager -E '
my $pm = Parallel::ForkManager->new(30);
for my $file (1..30) {
$pm->start and next;
say "Processing file $file";
sleep(1);
$pm->finish;
}
$pm->wait_all_children;
'
# Restore original perl environment
# https://stackoverflow.com/questions/25188575/switching-to-the-system-perl-using-perlbrew
perlbrew off # only for this session (terminal)
perlbrew switch-off # permanently
# Using the shebang line with perlbrew (-S to pass in args)
#!/usr/bin/env perl
#!/usr/bin/env -S perl -l
# Install with thread support.
perlbrew install perl-5.38.2 --thread
# Install multiple versions with and without thread support.
perlbrew install-multiple 5.38.2 blead --both thread
perlbrew switch perl-5.38.2-thread-multi
perl -V:'use.*thread.*'
# Upgrade current perl version.
perlbrew upgrade-perl
# Upgrade perlbrew
perlbrew self-upgrade
perlbrew version
# Upgrade cpanm
perlbrew install-cpanm
echo 'Unattended-Upgrade::Allowed-Origins:: "LP-PPA-mozillateam:${distro_codename}";' | sudo tee /etc/apt/apt.conf.d/51unattended-upgrades-firefox
#############################################################
## SQLite3 Database
#############################################################
# Install sqlite on Unix (after in zipping the amalgamation file. make sure these 3 are present:
# shell.c, sqlite3.c, sqlite3.h). rename to a.out to sqlite3
# (database, sqlite3)
gcc shell.c sqlite3.c -lpthread -ldl
# View all the tables in a database (database, sqlite3)
sqlite3 my.db '.tables'
# Turn on column names on query results (database, sqlite3)
sqlite3 my.db '.explain on' 'select * from page_groups'
# Print database structure and data (database, sqlite3)
sqlite3 my.db '.dump'
console.log('Watched time: ', newTime, oldTime);
this.$refs.form.values.AccountedTime = newTime;
});
#############################################################
## WII
#############################################################
# Write files/games to WII.
https://mariokartwii.com/showthread.php?tid=121
https://www.gametdb.com/Wii/Search
#############################################################
## Windows Bugs
#############################################################
# Windows stuck in control mode (Tobias Wulf,windows bug)
Recovery: Most of the time, Ctrl + Alt + Del re-sets key status
to normal if this is happening. (Then press Esc to exit system screen.)
( run in 0.670 second using v1.01-cache-2.11-cpan-3cd7ad12f66 )