Unix c programs using system calls

Hi friends, I have three questions. Looking forward to your wonderful replies! Hello, how would i be able to call ps in C programming? About system calls. Hi all, I am new here. I want to know about system call in detail. As system calls are also function. How system identifies it. System calls. Using system calls. Can someone share your knowledge as to how exactly system calls should be executed? Can they be typed like commands such as mkdir on the terminal itself?

Also, are there any websites which will show me an example of the output to expect when a system call like System calls? System calls for cp and mv. Which system calls are made for operations cp and mv 2 Replies.

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Write a C program to print "GfG" repeatedly without using loop, recursion and any control structure? Article Contributed By :. Easy Normal Medium Hard Expert. Writing code in comment? Please use ide. Load Comments. Additionally, you may not want or need the extra features the wrapper provides. You can also use system calls to perform functions not yet supported by glibc. If your copy of glibc is up to date, this will hardly be an issue, but developing on older distributions with newer kernels might require this technique.

The syscall function works as follows:. Arguments for the call go into arg1, arg2 above. Remember that most arguments, especially for returns, will require pointers to char arrays or memory allocated via the malloc function. For more interesting results, you could spin threads via the pthreads library and then call this function to see on which processor your thread is running. Sendfile provides an excellent example of enhancing performance through system calls.

The sendfile function copies data from one file descriptor to another. Rather than using multiple fread and fwrite functions, sendfile performs the transfer in kernel space, reducing overhead and thereby increasing performance.

To build these examples, you will need the development tools installed on your distribution.