How to get current CPU and RAM usage in Python?

The psutil library gives you information about CPU, RAM, etc., on a variety of platforms:

psutil is a module providing an interface for retrieving information on running processes and system utilization (CPU, memory) in a portable way by using Python, implementing many functionalities offered by tools like ps, top and Windows task manager. It currently supports Linux, Windows, OSX, Sun Solaris, FreeBSD, OpenBSD and NetBSD, both 32-bit and 64-bit architectures, with Python versions from 2.6 to 3.5 (users of Python 2.4 and 2.5 may use 2.1.3 version).

Some examples:

#!/usr/bin/env python
import psutil
# gives a single float value
psutil.cpu_percent()
# gives an object with many fields
psutil.virtual_memory()
# you can convert that object to a dictionary 
dict(psutil.virtual_memory()._asdict())
# you can have the percentage of used RAM
psutil.virtual_memory().percent
79.2
# you can calculate percentage of available memory
psutil.virtual_memory().available * 100 / psutil.virtual_memory().total
20.8

Here's other documentation that provides more concepts and interest concepts:

https://psutil.readthedocs.io/en/latest/

---

Use the psutil library. On Ubuntu 18.04, pip installed 5.5.0 (latest version) as of 1-30-2019. Older versions may behave somewhat differently. You can check your version of psutil by doing this in Python:

from __future__ import print_function  # for Python2
import psutil
print(psutil.__versi‌​on__)

To get some memory and CPU stats:

from __future__ import print_function
import psutil
print(psutil.cpu_percent())
print(psutil.virtual_memory())  # physical memory usage
print('memory % used:', psutil.virtual_memory()[2])

The virtual_memory (tuple) will have the percent memory used system-wide. This seemed to be overestimated by a few percent for me on Ubuntu 18.04.

You can also get the memory used by the current Python instance:

import os
import psutil
pid = os.getpid()
python_process = psutil.Process(pid)
memoryUse = python_process.memory_info()[0]/2.**30  # memory use in GB...I think
print('memory use:', memoryUse)

which gives the current memory use of your Python script.

There are some more in-depth examples on the pypi page for psutil.

---

Only for Linux: One-liner for the RAM usage with only stdlib dependency:

import os
tot_m, used_m, free_m = map(int, os.popen('free -t -m').readlines()[-1].split()[1:])

---

One can get real time CPU and RAM monitoring by combining tqdm and psutil. It may be handy when running heavy computations / processing.

https://i.stack.imgur.com/NaEJh.gif

It also works in Jupyter without any code changes:

https://i.stack.imgur.com/TWCpo.gif

from tqdm import tqdm
from time import sleep
import psutil

with tqdm(total=100, desc='cpu%', position=1) as cpubar, tqdm(total=100, desc='ram%', position=0) as rambar:
    while True:
        rambar.n=psutil.virtual_memory().percent
        cpubar.n=psutil.cpu_percent()
        rambar.refresh()
        cpubar.refresh()
        sleep(0.5)

It's convenient to put those progress bars in separate process using multiprocessing library.

This code snippet is also available as a gist.

---

Below codes, without external libraries worked for me. I tested at Python 2.7.9

CPU Usage

import os
    
CPU_Pct=str(round(float(os.popen('''grep 'cpu ' /proc/stat | awk '{usage=($2+$4)*100/($2+$4+$5)} END {print usage }' ''').readline()),2))
print("CPU Usage = " + CPU_Pct)  # print results

And Ram Usage, Total, Used and Free

import os
mem=str(os.popen('free -t -m').readlines())
"""
Get a whole line of memory output, it will be something like below
['             total       used       free     shared    buffers     cached\n', 
'Mem:           925        591        334         14         30        355\n', 
'-/+ buffers/cache:        205        719\n', 
'Swap:           99          0         99\n', 
'Total:        1025        591        434\n']
 So, we need total memory, usage and free memory.
 We should find the index of capital T which is unique at this string
"""
T_ind=mem.index('T')
"""
Than, we can recreate the string with this information. After T we have,
"Total:        " which has 14 characters, so we can start from index of T +14
and last 4 characters are also not necessary.
We can create a new sub-string using this information
"""
mem_G=mem[T_ind+14:-4]
"""
The result will be like
1025        603        422
we need to find first index of the first space, and we can start our substring
from from 0 to this index number, this will give us the string of total memory
"""
S1_ind=mem_G.index(' ')
mem_T=mem_G[0:S1_ind]
"""
Similarly we will create a new sub-string, which will start at the second value. 
The resulting string will be like
603        422
Again, we should find the index of first space and than the 
take the Used Memory and Free memory.
"""
mem_G1=mem_G[S1_ind+8:]
S2_ind=mem_G1.index(' ')
mem_U=mem_G1[0:S2_ind]

mem_F=mem_G1[S2_ind+8:]
print 'Summary = ' + mem_G
print 'Total Memory = ' + mem_T +' MB'
print 'Used Memory = ' + mem_U +' MB'
print 'Free Memory = ' + mem_F +' MB'

---

To get a line-by-line memory and time analysis of your program, I suggest using memory_profiler and line_profiler.

Installation:

# Time profiler
$ pip install line_profiler
# Memory profiler
$ pip install memory_profiler
# Install the dependency for a faster analysis
$ pip install psutil

The common part is, you specify which function you want to analyse by using the respective decorators.

Example: I have several functions in my Python file main.py that I want to analyse. One of them is linearRegressionfit(). I need to use the decorator @profile that helps me profile the code with respect to both: Time & Memory.

Make the following changes to the function definition

@profile
def linearRegressionfit(Xt,Yt,Xts,Yts):
    lr=LinearRegression()
    model=lr.fit(Xt,Yt)
    predict=lr.predict(Xts)
    # More Code

For Time Profiling,

Run:

$ kernprof -l -v main.py

Output

Total time: 0.181071 s
File: main.py
Function: linearRegressionfit at line 35

Line #      Hits         Time  Per Hit   % Time  Line Contents
==============================================================
    35                                           @profile
    36                                           def linearRegressionfit(Xt,Yt,Xts,Yts):
    37         1         52.0     52.0      0.1      lr=LinearRegression()
    38         1      28942.0  28942.0     75.2      model=lr.fit(Xt,Yt)
    39         1       1347.0   1347.0      3.5      predict=lr.predict(Xts)
    40                                           
    41         1       4924.0   4924.0     12.8      print("train Accuracy",lr.score(Xt,Yt))
    42         1       3242.0   3242.0      8.4      print("test Accuracy",lr.score(Xts,Yts))

For Memory Profiling,

Run:

$ python -m memory_profiler main.py

Output

Filename: main.py

Line #    Mem usage    Increment   Line Contents
================================================
    35  125.992 MiB  125.992 MiB   @profile
    36                             def linearRegressionfit(Xt,Yt,Xts,Yts):
    37  125.992 MiB    0.000 MiB       lr=LinearRegression()
    38  130.547 MiB    4.555 MiB       model=lr.fit(Xt,Yt)
    39  130.547 MiB    0.000 MiB       predict=lr.predict(Xts)
    40                             
    41  130.547 MiB    0.000 MiB       print("train Accuracy",lr.score(Xt,Yt))
    42  130.547 MiB    0.000 MiB       print("test Accuracy",lr.score(Xts,Yts))

Also, the memory profiler results can also be plotted using matplotlib using

$ mprof run main.py
$ mprof plot

https://i.stack.imgur.com/EXEXg.png

line_profiler version == 3.0.2

memory_profiler version == 0.57.0

psutil version == 5.7.0

https://github.com/pra-dan/TAMPPA/raw/master/resources/mem_res.png

---

We chose to use usual information source for this because we could find instantaneous fluctuations in free memory and felt querying the meminfo data source was helpful. This also helped us get a few more related parameters that were pre-parsed.

Code

import os

linux_filepath = "/proc/meminfo"
meminfo = dict(
    (i.split()[0].rstrip(":"), int(i.split()[1]))
    for i in open(linux_filepath).readlines()
)
meminfo["memory_total_gb"] = meminfo["MemTotal"] / (2 ** 20)
meminfo["memory_free_gb"] = meminfo["MemFree"] / (2 ** 20)
meminfo["memory_available_gb"] = meminfo["MemAvailable"] / (2 ** 20)

Output for reference (we stripped all newlines for further analysis)

MemTotal: 1014500 kB MemFree: 562680 kB MemAvailable: 646364 kB Buffers: 15144 kB Cached: 210720 kB SwapCached: 0 kB Active: 261476 kB Inactive: 128888 kB Active(anon): 167092 kB Inactive(anon): 20888 kB Active(file): 94384 kB Inactive(file): 108000 kB Unevictable: 3652 kB Mlocked: 3652 kB SwapTotal: 0 kB SwapFree: 0 kB Dirty: 0 kB Writeback: 0 kB AnonPages: 168160 kB Mapped: 81352 kB Shmem: 21060 kB Slab: 34492 kB SReclaimable: 18044 kB SUnreclaim: 16448 kB KernelStack: 2672 kB PageTables: 8180 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 507248 kB Committed_AS: 1038756 kB VmallocTotal: 34359738367 kB VmallocUsed: 0 kB VmallocChunk: 0 kB HardwareCorrupted: 0 kB AnonHugePages: 88064 kB CmaTotal: 0 kB CmaFree: 0 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 43008 kB DirectMap2M: 1005568 kB

---

Here's something I put together a while ago, it's windows only but may help you get part of what you need done.

Derived from: "for sys available mem" http://msdn2.microsoft.com/en-us/library/aa455130.aspx

"individual process information and python script examples" http://www.microsoft.com/technet/scriptcenter/scripts/default.mspx?mfr=true

NOTE: the WMI interface/process is also available for performing similar tasks I'm not using it here because the current method covers my needs, but if someday it's needed to extend or improve this, then may want to investigate the WMI tools a vailable.

WMI for python:

http://tgolden.sc.sabren.com/python/wmi.html

The code:

'''
Monitor window processes

derived from:
>for sys available mem
http://msdn2.microsoft.com/en-us/library/aa455130.aspx

> individual process information and python script examples
http://www.microsoft.com/technet/scriptcenter/scripts/default.mspx?mfr=true

NOTE: the WMI interface/process is also available for performing similar tasks
        I'm not using it here because the current method covers my needs, but if someday it's needed
        to extend or improve this module, then may want to investigate the WMI tools available.
        WMI for python:
        http://tgolden.sc.sabren.com/python/wmi.html
'''

__revision__ = 3

import win32com.client
from ctypes import *
from ctypes.wintypes import *
import pythoncom
import pywintypes
import datetime


class MEMORYSTATUS(Structure):
    _fields_ = [
                ('dwLength', DWORD),
                ('dwMemoryLoad', DWORD),
                ('dwTotalPhys', DWORD),
                ('dwAvailPhys', DWORD),
                ('dwTotalPageFile', DWORD),
                ('dwAvailPageFile', DWORD),
                ('dwTotalVirtual', DWORD),
                ('dwAvailVirtual', DWORD),
                ]


def winmem():
    x = MEMORYSTATUS() # create the structure
    windll.kernel32.GlobalMemoryStatus(byref(x)) # from cytypes.wintypes
    return x    


class process_stats:
    '''process_stats is able to provide counters of (all?) the items available in perfmon.
    Refer to the self.supported_types keys for the currently supported 'Performance Objects'
    
    To add logging support for other data you can derive the necessary data from perfmon:
    ---------
    perfmon can be run from windows 'run' menu by entering 'perfmon' and enter.
    Clicking on the '+' will open the 'add counters' menu,
    From the 'Add Counters' dialog, the 'Performance object' is the self.support_types key.
    --> Where spaces are removed and symbols are entered as text (Ex. # == Number, % == Percent)
    For the items you wish to log add the proper attribute name in the list in the self.supported_types dictionary,
    keyed by the 'Performance Object' name as mentioned above.
    ---------
    
    NOTE: The 'NETFramework_NETCLRMemory' key does not seem to log dotnet 2.0 properly.
    
    Initially the python implementation was derived from:
    http://www.microsoft.com/technet/scriptcenter/scripts/default.mspx?mfr=true
    '''
    def __init__(self,process_name_list=[],perf_object_list=[],filter_list=[]):
        '''process_names_list == the list of all processes to log (if empty log all)
        perf_object_list == list of process counters to log
        filter_list == list of text to filter
        print_results == boolean, output to stdout
        '''
        pythoncom.CoInitialize() # Needed when run by the same process in a thread
        
        self.process_name_list = process_name_list
        self.perf_object_list = perf_object_list
        self.filter_list = filter_list
        
        self.win32_perf_base = 'Win32_PerfFormattedData_'
        
        # Define new datatypes here!
        self.supported_types = {
                                    'NETFramework_NETCLRMemory':    [
                                                                        'Name',
                                                                        'NumberTotalCommittedBytes',
                                                                        'NumberTotalReservedBytes',
                                                                        'NumberInducedGC',    
                                                                        'NumberGen0Collections',
                                                                        'NumberGen1Collections',
                                                                        'NumberGen2Collections',
                                                                        'PromotedMemoryFromGen0',
                                                                        'PromotedMemoryFromGen1',
                                                                        'PercentTimeInGC',
                                                                        'LargeObjectHeapSize'
                                                                     ],
                                                                     
                                    'PerfProc_Process':              [
                                                                          'Name',
                                                                          'PrivateBytes',
                                                                          'ElapsedTime',
                                                                          'IDProcess',# pid
                                                                          'Caption',
                                                                          'CreatingProcessID',
                                                                          'Description',
                                                                          'IODataBytesPersec',
                                                                          'IODataOperationsPersec',
                                                                          'IOOtherBytesPersec',
                                                                          'IOOtherOperationsPersec',
                                                                          'IOReadBytesPersec',
                                                                          'IOReadOperationsPersec',
                                                                          'IOWriteBytesPersec',
                                                                          'IOWriteOperationsPersec'     
                                                                      ]
                                }
        
    def get_pid_stats(self, pid):
        this_proc_dict = {}
        
        pythoncom.CoInitialize() # Needed when run by the same process in a thread
        if not self.perf_object_list:
            perf_object_list = self.supported_types.keys()
                    
        for counter_type in perf_object_list:
            strComputer = "."
            objWMIService = win32com.client.Dispatch("WbemScripting.SWbemLocator")
            objSWbemServices = objWMIService.ConnectServer(strComputer,"root\cimv2")
        
            query_str = '''Select * from %s%s''' % (self.win32_perf_base,counter_type)
            colItems = objSWbemServices.ExecQuery(query_str) # "Select * from Win32_PerfFormattedData_PerfProc_Process")# changed from Win32_Thread        
        
            if len(colItems) > 0:        
                for objItem in colItems:
                    if hasattr(objItem, 'IDProcess') and pid == objItem.IDProcess:
                        
                            for attribute in self.supported_types[counter_type]:
                                eval_str = 'objItem.%s' % (attribute)
                                this_proc_dict[attribute] = eval(eval_str)
                                
                            this_proc_dict['TimeStamp'] = datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S.') + str(datetime.datetime.now().microsecond)[:3]
                            break

        return this_proc_dict      
                      
        
    def get_stats(self):
        '''
        Show process stats for all processes in given list, if none given return all processes   
        If filter list is defined return only the items that match or contained in the list
        Returns a list of result dictionaries
        '''    
        pythoncom.CoInitialize() # Needed when run by the same process in a thread
        proc_results_list = []
        if not self.perf_object_list:
            perf_object_list = self.supported_types.keys()
                    
        for counter_type in perf_object_list:
            strComputer = "."
            objWMIService = win32com.client.Dispatch("WbemScripting.SWbemLocator")
            objSWbemServices = objWMIService.ConnectServer(strComputer,"root\cimv2")
        
            query_str = '''Select * from %s%s''' % (self.win32_perf_base,counter_type)
            colItems = objSWbemServices.ExecQuery(query_str) # "Select * from Win32_PerfFormattedData_PerfProc_Process")# changed from Win32_Thread
       
            try:  
                if len(colItems) > 0:
                    for objItem in colItems:
                        found_flag = False
                        this_proc_dict = {}
                        
                        if not self.process_name_list:
                            found_flag = True
                        else:
                            # Check if process name is in the process name list, allow print if it is
                            for proc_name in self.process_name_list:
                                obj_name = objItem.Name
                                if proc_name.lower() in obj_name.lower(): # will log if contains name
                                    found_flag = True
                                    break
                                
                        if found_flag:
                            for attribute in self.supported_types[counter_type]:
                                eval_str = 'objItem.%s' % (attribute)
                                this_proc_dict[attribute] = eval(eval_str)
                                
                            this_proc_dict['TimeStamp'] = datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S.') + str(datetime.datetime.now().microsecond)[:3]
                            proc_results_list.append(this_proc_dict)
                    
            except pywintypes.com_error, err_msg:
                # Ignore and continue (proc_mem_logger calls this function once per second)
                continue
        return proc_results_list     

    
def get_sys_stats():
    ''' Returns a dictionary of the system stats'''
    pythoncom.CoInitialize() # Needed when run by the same process in a thread
    x = winmem()
    
    sys_dict = { 
                    'dwAvailPhys': x.dwAvailPhys,
                    'dwAvailVirtual':x.dwAvailVirtual
                }
    return sys_dict

    
if __name__ == '__main__':
    # This area used for testing only
    sys_dict = get_sys_stats()
    
    stats_processor = process_stats(process_name_list=['process2watch'],perf_object_list=[],filter_list=[])
    proc_results = stats_processor.get_stats()
    
    for result_dict in proc_results:
        print result_dict
        
    import os
    this_pid = os.getpid()
    this_proc_results = stats_processor.get_pid_stats(this_pid)
    
    print 'this proc results:'
    print this_proc_results

---

I feel like these answers were written for Python 2, and in any case nobody's made mention of the standard resource package that's available for Python 3. It provides commands for obtaining the resource limits of a given process (the calling Python process by default). This isn't the same as getting the current usage of resources by the system as a whole, but it could solve some of the same problems like e.g. "I want to make sure I only use X much RAM with this script."

---

This aggregate all the goodies: psutil + os to get Unix & Windows compatibility: That allows us to get:

CPU memory disk

code:

import os
import psutil  # need: pip install psutil

In [32]: psutil.virtual_memory()
Out[32]: svmem(total=6247907328, available=2502328320, percent=59.9, used=3327135744, free=167067648, active=3671199744, inactive=1662668800,     buffers=844783616, cached=1908920320, shared=123912192, slab=613048320)

In [33]: psutil.virtual_memory().percent
Out[33]: 60.0

In [34]: psutil.cpu_percent()
Out[34]: 5.5

In [35]: os.sep
Out[35]: '/'

In [36]: psutil.disk_usage(os.sep)
Out[36]: sdiskusage(total=50190790656, used=41343860736, free=6467502080, percent=86.5)

In [37]: psutil.disk_usage(os.sep).percent
Out[37]: 86.5

---

"... current system status (current CPU, RAM, free disk space, etc.)" And "*nix and Windows platforms" can be a difficult combination to achieve.

The operating systems are fundamentally different in the way they manage these resources. Indeed, they differ in core concepts like defining what counts as system and what counts as application time.

"Free disk space"? What counts as "disk space?" All partitions of all devices? What about foreign partitions in a multi-boot environment?

I don't think there's a clear enough consensus between Windows and *nix that makes this possible. Indeed, there may not even be any consensus between the various operating systems called Windows. Is there a single Windows API that works for both XP and Vista?

---

Taken feedback from first response and done small changes

#!/usr/bin/env python
#Execute commond on windows machine to install psutil>>>>python -m pip install psutil
import psutil

print ('                                                                   ')
print ('----------------------CPU Information summary----------------------')
print ('                                                                   ')

# gives a single float value
vcc=psutil.cpu_count()
print ('Total number of CPUs :',vcc)

vcpu=psutil.cpu_percent()
print ('Total CPUs utilized percentage :',vcpu,'%')

print ('                                                                   ')
print ('----------------------RAM Information summary----------------------')
print ('                                                                   ')
# you can convert that object to a dictionary 
#print(dict(psutil.virtual_memory()._asdict()))
# gives an object with many fields
vvm=psutil.virtual_memory()

x=dict(psutil.virtual_memory()._asdict())

def forloop():
    for i in x:
        print (i,"--",x[i]/1024/1024/1024)#Output will be printed in GBs

forloop()
print ('                                                                   ')
print ('----------------------RAM Utilization summary----------------------')
print ('                                                                   ')
# you can have the percentage of used RAM
print('Percentage of used RAM :',psutil.virtual_memory().percent,'%')
#79.2
# you can calculate percentage of available memory
print('Percentage of available RAM :',psutil.virtual_memory().available * 100 / psutil.virtual_memory().total,'%')
#20.8

---

This script for CPU usage:

import os

def get_cpu_load():
    """ Returns a list CPU Loads"""
    result = []
    cmd = "WMIC CPU GET LoadPercentage "
    response = os.popen(cmd + ' 2>&1','r').read().strip().split("\r\n")
    for load in response[1:]:
       result.append(int(load))
    return result

if __name__ == '__main__':
    print get_cpu_load()

---

For CPU details use psutil library https://psutil.readthedocs.io/en/latest/#cpu

For RAM Frequency (in MHz) use the built in Linux library dmidecode and manipulate the output a bit ;). this command needs root permission hence supply your password too. just copy the following commend replacing mypass with your password

import os os.system("echo mypass | sudo -S dmidecode -t memory | grep 'Clock Speed' | cut -d ':' -f2") ------------------- Output --------------------------- 1600 MT/s Unknown 1600 MT/s Unknown 0

more specificly [i for i in os.popen("echo mypass | sudo -S dmidecode -t memory | grep 'Clock Speed' | cut -d ':' -f2").read().split(' ') if i.isdigit()]

-------------------------- output ------------------------- ['1600', '1600']

---

you can read /proc/meminfo to get used memory

file1 = open('/proc/meminfo', 'r') 

for line in file1: 
    if 'MemTotal' in line: 
        x = line.split()
        memTotal = int(x[1])
        
    if 'Buffers' in line: 
        x = line.split()
        buffers = int(x[1])
        
    if 'Cached' in line and 'SwapCached' not in line: 
        x = line.split()
        cached = int(x[1])
    
    if 'MemFree' in line: 
        x = line.split()
        memFree = int(x[1])

file1.close()

percentage_used = int ( ( memTotal - (buffers + cached + memFree) ) / memTotal * 100 )
print(percentage_used)

---

Based on the cpu usage code by @Hrabal, this is what I use:

from subprocess import Popen, PIPE

def get_cpu_usage():
    ''' Get CPU usage on Linux by reading /proc/stat '''

    sub = Popen(('grep', 'cpu', '/proc/stat'), stdout=PIPE, stderr=PIPE)
    top_vals = [int(val) for val in sub.communicate()[0].split('\n')[0].split[1:5]]

    return (top_vals[0] + top_vals[2]) * 100. /(top_vals[0] + top_vals[2] + top_vals[3])

---

You can use psutil or psmem with subprocess example code

import subprocess
cmd =   subprocess.Popen(['sudo','./ps_mem'],stdout=subprocess.PIPE,stderr=subprocess.PIPE) 
out,error = cmd.communicate() 
memory = out.splitlines()

Reference

https://github.com/Leo-g/python-flask-cmd

---

Run with crontab won't print pid

Setup: */1 * * * * sh dog.sh this line in crontab -e

import os
import re

CUT_OFF = 90

def get_cpu_load():
    cmd = "ps -Ao user,uid,comm,pid,pcpu --sort=-pcpu | head -n 2 | tail -1"
    response = os.popen(cmd, 'r').read()
    arr = re.findall(r'\S+', response)
    print(arr)
    needKill = float(arr[-1]) > CUT_OFF
    if needKill:
        r = os.popen(f"kill -9 {arr[-2]}")
        print('kill:', r)

if __name__ == '__main__':
    # Test CPU with 
    # $ stress --cpu 1
    # crontab -e
    # Every 1 min
    # */1 * * * * sh dog.sh
    # ctlr o, ctlr x
    # crontab -l
    print(get_cpu_load())

---

Shell-out not needed for @CodeGench's solution, so assuming Linux and Python's standard libraries:

def cpu_load(): 
    with open("/proc/stat", "r") as stat:
        (key, user, nice, system, idle, _) = (stat.readline().split(None, 5))
    assert key == "cpu", "'cpu ...' should be the first line in /proc/stat"
    busy = int(user) + int(nice) + int(system)
    return 100 * busy / (busy + int(idle))

---

I don't believe that there is a well-supported multi-platform library available. Remember that Python itself is written in C so any library is simply going to make a smart decision about which OS-specific code snippet to run, as you suggested above.

---