Simple Example Program For Read And Write System Call

Simple Example For Read System Call

here's a simple example of how to use the read system call in Linux:

#include <stdio.h>
#include <unistd.h>

int main() {
    char buffer[100];
    int num_bytes = read(STDIN_FILENO, buffer, 100);
    printf("Read %d bytes from stdin: %s\n", num_bytes, buffer);
    return 0;
}

In this example, we include the necessary headers (stdio.h and unistd.h) and declare a character buffer of size 100 to store the input we read from the user.

Then, we call the read system call with three arguments: the file descriptor of the input stream (STDIN_FILENO), the buffer to read the input into (buffer), and the maximum number of bytes to read (100).

The read system call will block until input is available, and will then read up to 100 bytes from the input stream into buffer. The number of bytes actually read is returned by the function and stored in the num_bytes variable.

Finally, we print out the number of bytes read along with the input we read from the user using printf.

Note that this is just a simple example and in practice, you would want to handle errors and edge cases properly.

Simple Example For Write System Call

here's a simple example for the write system call in Linux:

#include <unistd.h>
#include <fcntl.h>

int main() {
    int fd = open("output.txt", O_WRONLY | O_CREAT, 0644);
    write(fd, "Hello, World!", 13);
    close(fd);
    return 0;
}