How to write a file with C in Linux?

Question

I want to rewrite the \"cp\" command of Linux. So this program will work like #./a.out originalfile copiedfile. I can open the file, create new file but can\'t writ

Answer 1

You have to allocate the buffer with mallock, and give the read write the pointer to it.

#include 
#include 
#include 
#include 
#include 
int main(){
    ssize_t nrd;
    int fd; 
    int fd1;

    char* buffer = malloc(100*sizeof(char));
    fd = open("bli.txt", O_RDONLY);
    fd1 = open("bla.txt", O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR);
    while (nrd = read(fd,buffer,sizeof(buffer))) {
        write(fd1,buffer,nrd);
    }   

    close(fd);
    close(fd1);
    free(buffer);
    return 0;
}

Make sure that the rad file exists and contains something. It's not perfect but it works.