So in this know, we are going to talk about our system calls solar system Kasprowicz and travels to
the operating system services, so if there is any service provided by the operating system to open
a file or open an image, you can call that service.
You can use that service using the system.
So in summary, we have to use the system called numbers in order to call that system call.
So each system can't have a specific number like unique number.
You need to use that number to call the system call.
So some other system calls.
Exemplary examples are right.
Open.
Close, right.
Right.
The data into the specified destination and open function opens you, Shankar Wolfenson, file out an
image and system just closes the pointer.
And we need to send the arguments to the system cause to modify our design, file our own image, and
the parts should be sent as an argument, should be Sandison arguments, and these arguments should
be placed in the registers.
OK, up to now, you may seem confusing.
Now, let me tell the Linux system CARTERVILLE So this is taken from Sharon Stone website.
And here you have you will see the so many system calls a system called for right open and so on.
And one of the important thing is if you have a program, Lindsay, you can just import the hydrofoil
related to this system and you can just.
Use this system as a normal functions.
So if you have to, the file handling in the C programming language can see right, open, close.
Yes, a normal functions, right.
So these are the very system calls.
You can check the website for more tramcars.
Now we see about the right system.
So right, right to file descriptor specified.
OK, now let's see the syntax.
The right system car is included in the unit study headwall.
So if you want to use it in the C programming language, you need to write this line and then you can
use this function.
So the return value of the write function is essay's.
Underscore that, which is a number which returns the status of the this system, whether it's successful
or failed.
So the first argument is the file descriptor, whether you want to write the input output or standard
error or to a file descriptor.
So gyro stands for standard input and one stands for Standard Output and Pushtuns for standard error.
You want to write some data to output, you need to specify one.
And this points to the powerful is the actual data you want to write to this nation.
And this is underscored the difference, the number of bites and the count actually divides the number
of birds the size increase the number and the number of deaths.
And this defines the number of this buffer you need to write into this file descriptor.
So I thought you understood.
So let me explain again with some simple words.
So these three arguments specify where to write the data and what to read the data and how much to write
the data.
So if I say 50 bytes of this buffer should be placed in this file descriptor or an output.
So this is very simple system called.
Now let's see how to call the system using our assembly language.
So I have it in this this syntax which we have seen in the previous right now, the right system should
be placed for years and then this argument should be in easier.
And if there are more than three arguments you need to place in EASA and the registers.
All right, now we need to press the file descriptor number, which is which is an integer should be
President Ebix, and you need to put the pointer toward Buffer in X and you need to write the number
of bytes you want to write to and you need to put that number in index after putting all these values.
You need to you need to write this instruction card directly to the software.
So what this software actually does is it will enable the handler.
So this intrapreneur will get a degree and will check the contents of the eggs.
So since X contains the number of write, it performs right.
Operation with this with this argument.
And it also takes Ebix, Ishaq's and UTX and then that accordingly that this the system and intrapreneur
will perform this system card with this argument.
I hope we understood this, so I will repeat it again.
We need to press the right system cause no any X and this first argument and every second argument extra
to react.
And we need to call this software and.
We need to preface this by using the mourning section, do don't worry about these guys will cover all
this in part, and then we need to find recorder in the city, 1832.
But this is a softer interest and it will perform the system called.