Without using remove() function How to delete a file in C program - c

Question

I am trying to delete a file in c program. Assume that the file is located in current directory of source file. I have searched a lot but didn't get any solution. Everyone is suggesting to use remove() function.
Here is my source code:
#include <stdio.h>
#include <stdlib.h>
int main()
{
FILE *fp;
int delete_status;
char del[50];
printf("Enter a file name to delete it: ");
gets(del);
delete_status = remove(del);
if(delete_status!=0) {
printf("File can not be deleted!\nFile does not exist in current directory\n");
}
else printf("File %s has been deleted successfully!\n", del);
return 0;
}
Is there any way to remove file without using remove() function. I want to code manually without using any other stl built in function.

Answer 1

You can replace remove() with unlink() (for files) and rmdir() (for directories).

Answer 2

You can check this answer. You should try to read a system programming book where you can learn about uses like INTERNAL_SYSCALL.
You can skim through the functions referred in the posts like unlink() etc.
EDIT: actually somehow you will end up using a system-call at some level. You probably trying to achieve the operation of deleting a file from different abstraction level.(remove() system call will also use INTERNAL_SYSCALL which nothing but a system call).
Now from low level deleting a file doesn't mean we are erasing something. We are just considering the space as free space(free pool of memory) and then any metadata related to that file is also freed. To achieve that you need to implement a filesystem that allocates memory,deletes it..using device level instructions.

Answer 3

Call unlink for files, rmdir for directories. You could easily check which a file is using stat and then call the correct function.
struct stat sb;
if (!stat(filename, &sb))
{
if (S_ISDIR(sb.st_mode))
rmdir(filename);
else
unlink(filename);
}
Include <sys/stat.h> for stat and S_ISDIR, <unistd.h> for rmdir and unlink.
Oh, and per your comment:
All of you didn't understand my needs and requirement. I know that it is posible to delete a file using standard library function like remove(), unlink(), rm() etc. But I want to code manually without using any built in function.
Have fun reproducing unlink's source code.

Answer 4

I think what you need to know is unlink() function. For deleting files, remove() internally calls unlink() itself. Check the man page for details.
However, first I suggest you to change the gets() with fgets(). Also, int main() should be int main(void).

Answer 5

One can use fork and exec to run the rm command over shell.
sample code:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
int main(){
int status;
pid_t pid = fork();
if(-1 == pid){
printf("fork() failed");
exit(EXIT_FAILURE);
}else if(pid == 0){
execl("/bin/sh", "sh", "-c", "rm /tmp/sandeep_reve.txt", (char *) NULL);
}else{
printf("Fork with id %ld\n",(long)pid);
waitpid(pid,&status,0);
}
return 0;
}

Answer 6

Use system():
PART I:(Delete file)
#include <stdio.h>
#include <string.h>
int main()
{
FILE *fp;
int delete_status;
char path[100],order[]="del ";//del for delete file, if change del to rd is delete folder(**Code at part 2)
printf("Enter a path of file to delete it: ");
gets(path);
strcat(order,path);//Order
fp = fopen(path,"r");
if(fp != NULL){//Check file whether or not exist
fclose(fp);
system(order);//Del file
printf("Delete successfully");
}else{
perror("ERROR");
fclose(fp);
}
return 0;
}
For example, you want to delete 1.txt.Then, you may put the c program in the same file and then intput 1.txt or enter whole path of the file.(e.g C:\User\desktop\1.txt)
PART II :(Delete folder)
#include <stdio.h>
#include <string.h>
int main()
{
FILE *fp;
int delete_status,i = 1;
char path[100],order[] = "rd ";//del -> rd
printf("Enter a path of file to delete it: ");
gets(path);
strcat(order,path);
system(order);
return 0;
}