Saturday, August 9, 2014

These are a list of various unix system calls that are implemented in C. If you have any doubts, please let me know.

PROGRAM DEVELOPMENT

#include<stdio.h>
#include<dirent.h>
struct dirent *dptr;
void main(int argc, char *argv[])
{
  char buff[100];
  DIR *dirp;
  printf("\n\nEnter Directory Name: ");
  scanf("%s",buff);
  if((dirp=opendir(buff))==NULL)
  {
   printf("\n The given directory does not exist\n");
   exit(1);
  }
  while(dptr=readdir(dirp))
  {
    printf("%s\n",dptr->d_name);
  }
  closedir(dirp);
}
























PROGRAM DEVELOPMENT

#include<stdio.h>
#include<unistd.h>
main()
{
  int pid,pid1,pid2;
  pid=fork();
  if(pid==-1)
  {
    printf("ERROR IN PROCESS CREATION\n");
    exit(1);
  }
  if(pid!=0)
  {
   pid1=getpid();
   printf("\nThe parent process id is %d\n",pid1);
   }
  else
   {
    pid2=getpid();
   printf("\nThe child process id is %d\n",pid2);
  }

}













PROGRAM DEVELOPMENT

#include<stdio.h>
int main()
{
  int fd;
  if((fd=open("file.dat"))==-1)
  {
   perror("cannot open the file.dat");
   exit(0);
  }
  else
  printf("\nFILE OPENED SUCCESSFULLY");
  return 0;
}

















PROGRAM DEVELOPMENT

#include<stdio.h>
main()
{
 char b[20];
 int fd,xr;
 if((fd=open("balaji",0))==-1)
 {
  printf("Cannot open file\n");
  exit(1);
 }
 do
 {
   xr=read(fd,b,20);
   b[xr]='\0';
   printf("%s",b);
 }
while(xr==20);
 close(fd);
}















PROGRAM DEVELOPMENT

#include<stdio.h>
main(int ac,char *av[])
 {
  int fd;
  int i=1,j=0;
  char *sep="";
  printf("%s",av[1]);
  if(ac<1)
  {
   printf("\n INSUFFICIENT ARGUMENTS");
   exit(1);
  }
  if((fd=open("balaji",0660))==-1)
  {
   printf("\n cannot create the file");
   exit(1);
  }
  while(i<ac)
  {
 j=write(fd,av[i],(unsigned)strlen(av[i]));
  printf("%d",j);
   write(fd,sep,(unsigned)strlen(sep));
   i++;
   }
   close(fd);
}










PROGRAM DEVELOPMENT

#include<stdio.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/stat.h>
int main()
{
 int s;
 struct stat st;
  s=stat("sss.c",&st);
  if(s<0)
  {
   printf("use of stat() is unsuccessful\n");
  exit(0); 
   }
   printf("\ninode number of sss.c file is %d",st.st_ino);
   printf("\nnumber of links to sss.c is %d",st.st_nlink);
   printf("\nfile permissions of sss.c file is %d",st.st_mode);
   printf("\nsize of sss.c file is %d",st.st_size);
   printf("\nlast access time of sss.c file is %d\n",st.st_atime);
}


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