Difference between revisions of "Device (C++)"

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|(constructor)[private]
 
|(constructor)[private]
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|constructs Device
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|constructs device, inaccessible from user code, new device object could be constructed only by DeviceScanner instance
 
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|(destructor)
 
|(destructor)
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|destroys Device
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|destroys device
 
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|operator=[deleted]
 
|operator=[deleted]
 
|not copy assignable
 
|not copy assignable
 
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|'''Supported commands and parameters'''
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|''''''Supported commands and parameters''''''
 
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|commands
 
|commands
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<tbody><tr class="t-dsc">
 
<tbody><tr class="t-dsc">
 
<td>  <div class="t-dsc-member-div t-dsc-member-nobold-div"><div><a href="/w/cpp/thread/mutex/mutex" title="cpp/thread/mutex/mutex"> <span class="t-lines"><span>(constructor)</span></span></a></div></div>
 
<td>  <div class="t-dsc-member-div t-dsc-member-nobold-div"><div><a href="/w/cpp/thread/mutex/mutex" title="cpp/thread/mutex/mutex"> <span class="t-lines"><span>(constructor)</span></span></a></div></div>

Revision as of 10:22, 25 April 2018

Neuro::Device

Defined in header <device/device.h>
class Device final;

The Device class is an abstraction for NeuroMD BLE devices. This abstraction provides functions for changing of device state by executing commands and setting parameters. Each device have different sets of supported commands and parameters, Device class has functions designed to get information about these sets.

Member functions

(constructor)[private] constructs device, inaccessible from user code, new device object could be constructed only by DeviceScanner instance
(destructor) destroys device
operator=[deleted] not copy assignable
'Supported commands and parameters'
commands returns

<tbody><tr class="t-dsc">

<td>
<a href="/w/cpp/thread/mutex/mutex" title="cpp/thread/mutex/mutex"> (constructor)</a>

</td> <td> constructs the mutex
(public member function) <a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/thread/mutex/dsc_constructor&action=edit">[edit]</a> </td></tr>

<tr class="t-dsc">

<td>
<a href="/w/cpp/thread/mutex/%7Emutex" title="cpp/thread/mutex/~mutex"> (destructor)</a>

</td> <td> destroys the mutex
(public member function) <a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/thread/mutex/dsc_destructor&action=edit">[edit]</a> </td></tr>

<tr class="t-dsc">

<td>
operator=
[deleted]

</td> <td> not copy-assignable
(public member function) <a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/thread/mutex/dsc_operator%3D&action=edit">[edit]</a> </td></tr>


<tr>

<td colspan="2">
Locking

</td></tr>

<tr class="t-dsc">

<td>
<a href="/w/cpp/thread/mutex/lock" title="cpp/thread/mutex/lock"> lock</a>

</td> <td> locks the mutex, blocks if the mutex is not available
(public member function) <a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/thread/mutex/dsc_lock&action=edit">[edit]</a> </td></tr>

<tr class="t-dsc">

<td>
<a href="/w/cpp/thread/mutex/try_lock" title="cpp/thread/mutex/try lock"> try_lock</a>

</td> <td> tries to lock the mutex, returns if the mutex is not available
(public member function) <a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/thread/mutex/dsc_try_lock&action=edit">[edit]</a> </td></tr>

<tr class="t-dsc">

<td>
<a href="/w/cpp/thread/mutex/unlock" title="cpp/thread/mutex/unlock"> unlock</a>

</td> <td> unlocks the mutex
(public member function) <a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/thread/mutex/dsc_unlock&action=edit">[edit]</a> </td></tr>


<tr>

<td colspan="2">
Native handle

</td></tr>

<tr class="t-dsc">

<td>
<a href="/w/cpp/thread/mutex/native_handle" title="cpp/thread/mutex/native handle"> native_handle</a>

</td> <td> returns the underlying implementation-defined native handle object
(public member function) <a rel="nofollow" class="external text" href="http://en.cppreference.com/mwiki/index.php?title=Template:cpp/thread/mutex/dsc_native_handle&action=edit">[edit]</a> </td></tr> </tbody></table> |}

[<a href="/mwiki/index.php?title=cpp/thread/mutex&action=edit&section=3" title="Edit section: Notes">edit</a>] Notes

std::mutex is usually not accessed directly: <a href="/w/cpp/thread/unique_lock" title="cpp/thread/unique lock">std::unique_lock</a>, <a href="/w/cpp/thread/lock_guard" title="cpp/thread/lock guard">std::lock_guard</a>, or std::scoped_lock (since C++17) manage locking in a more exception-safe manner.

[<a href="/mwiki/index.php?title=cpp/thread/mutex&action=edit&section=4" title="Edit section: Example">edit</a>] Example

This example shows how a mutex can be used to protect a <a href="/w/cpp/container/map" title="cpp/container/map">std::map</a> shared between two threads.

Run this code
<span class="co2">#include <iostream></span>
<span class="co2">#include <map></span>
<span class="co2">#include <string></span>
<span class="co2">#include <chrono></span>
<span class="co2">#include <thread></span>
<span class="co2">#include <mutex></span>
 
<a href="http://en.cppreference.com/w/cpp/container/map"><span class="kw1281">std::<span class="me2">map</span></span></a><span class="sy1"><</span><a href="http://en.cppreference.com/w/cpp/string/basic_string"><span class="kw1230">std::<span class="me2">string</span></span></a>, <a href="http://en.cppreference.com/w/cpp/string/basic_string"><span class="kw1230">std::<span class="me2">string</span></span></a><span class="sy1">></span> g_pages<span class="sy4">;</span>
std<span class="sy4">::</span><span class="me2">mutex</span> g_pages_mutex<span class="sy4">;</span>
 
<span class="kw4">void</span> save_page<span class="br0">(</span><span class="kw4">const</span> <a href="http://en.cppreference.com/w/cpp/string/basic_string"><span class="kw1230">std::<span class="me2">string</span></span></a> <span class="sy3">&</span>url<span class="br0">)</span>
<span class="br0">{</span>
    <span class="co1">// simulate a long page fetch</span>
    <a href="http://en.cppreference.com/w/cpp/thread/sleep_for"><span class="kw2149">std::<span class="me2">this_thread</span><span class="sy4">::</span><span class="me2">sleep_for</span></span></a><span class="br0">(</span><a href="http://en.cppreference.com/w/cpp/chrono/duration"><span class="kw997">std::<span class="me2">chrono</span><span class="sy4">::</span><span class="me2">seconds</span></span></a><span class="br0">(</span><span class="nu0">2</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
    <a href="http://en.cppreference.com/w/cpp/string/basic_string"><span class="kw1230">std::<span class="me2">string</span></span></a> result <span class="sy1">=</span> <span class="st0">"fake content"</span><span class="sy4">;</span>
 
    <a href="http://en.cppreference.com/w/cpp/thread/lock_guard"><span class="kw2165">std::<span class="me2">lock_guard</span></span></a><span class="sy1"><</span>std<span class="sy4">::</span><span class="me2">mutex</span><span class="sy1">></span> guard<span class="br0">(</span>g_pages_mutex<span class="br0">)</span><span class="sy4">;</span>
    g_pages<span class="br0">[</span>url<span class="br0">]</span> <span class="sy1">=</span> result<span class="sy4">;</span>
<span class="br0">}</span>
 
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span> 
<span class="br0">{</span>
    <a href="http://en.cppreference.com/w/cpp/thread/thread"><span class="kw2146">std::<span class="me2">thread</span></span></a> t1<span class="br0">(</span>save_page, <span class="st0">"http://foo"</span><span class="br0">)</span><span class="sy4">;</span>
    <a href="http://en.cppreference.com/w/cpp/thread/thread"><span class="kw2146">std::<span class="me2">thread</span></span></a> t2<span class="br0">(</span>save_page, <span class="st0">"http://bar"</span><span class="br0">)</span><span class="sy4">;</span>
    t1.<span class="me1">join</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
    t2.<span class="me1">join</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// safe to access g_pages without lock now, as the threads are joined</span>
    <span class="kw1">for</span> <span class="br0">(</span><span class="kw4">const</span> <span class="kw4">auto</span> <span class="sy3">&</span>pair <span class="sy4">:</span> g_pages<span class="br0">)</span> <span class="br0">{</span>
        <a href="http://en.cppreference.com/w/cpp/io/cout"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> pair.<span class="me1">first</span> <span class="sy1"><<</span> <span class="st0">" => "</span> <span class="sy1"><<</span> pair.<span class="me1">second</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
    <span class="br0">}</span>
<span class="br0">}</span>

Output: 

http://bar => fake content
http://foo => fake content


</div>

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