System Command: DIR

[hqt]

I'm using system command DIR: this command list all folder in the present directory. But I don't know how to touch folder in this list.
Example:

#include<windows.h>
int main()
{
System("DIR"); //list all folder
//Example: folder A, folder B,...
}

And, I want to check if there is folder X in this directory, how can ?
Anyones who know this, please teach me.

thanks

[anduril462]

Since you're asking about "DIR", I assume this is a Windows machine. Look into the FindFirstFile function.

[Babkockdood]

Try chdir, or opendir if chdir isn't available. chdir will return -1 if the specified directory doesn't exist. opendir will return NULL if the specified directory doesn't exist.

Also, you can use DOS' FIND command to search the output of DIR for folder X.

C:\>DIR | FIND "folder X"

That command should output "folder X", if folder X exists, or nothing, if it doesn't.

[Adak]

This shows another way to do it, without using a system call. Change it around to your own directory and file name, of course.

If you use Pelles C, you need to first click on "Project" tab, project options, and compiler. Check the box for "Define Compatibility Names

/*Remember to go into project options and check the "Define compatibility names box. 
That gets rid of the "Target Architecture not defined", error.
*/
#include <dirent.h>    
#include <stdio.h>
#include <string.h>

int main(void) {
   int i=0;
   DIR *dir;
   struct dirent *direntry; //could be a file, or a directory

   dir = opendir("C:/Users/Adak");
   if(!dir) {
      printf("Error: directory did not open!\n");
      return 1;
   }

   while((direntry=readdir(dir))!=NULL) {
      if(++i < 20) 
         printf("%s\n",direntry->d_name);
      if((strcmp(direntry->d_name, "test.txt"))==0) {
         printf("\nThe %s file has been found\n",direntry->d_name);
         i=-99;  //just a flag value to show the file was found
         break;
      }

   }
   if(i!=-99)
      printf("\nThe test.txt file was not found\n");

   closedir(dir);

   printf("\n");
   return 0;
}

[CommonTater]

G'day Adak... dirent.h is not a standard C header, it may not exist on the OP's machine.

Since the DIR command is shelled, it's very likely he's on Windows so he needs to investigate FindFirstFile(), FindNextFile() and FindClose()

A nice trick is that if you already know the name of the file or folder, you can use FindFirstFile() as a search tool... it will return an error if the specified path is not present...

[Adak]

G'day Tater.

Anduril had a hyperlink to the findfirstfile() way to do it - I was looking for something that used C, instead of the Windows API. That's what it sounded like the OP was looking for (and I was curious myself).

Is there a standard C way to do this, without using either the Windows API functions, or non-standard C?

[laserlight]

Is there a standard C way to do this, without using either the Windows API functions, or non-standard C?

No. <dirent.h> is POSIX standard though.

[Salem]

Every directory in DOS/Windows has a special "file" called NUL (similar to CON and PRN devices)
So if you try and open it, and succeed, then the directory exists.

fp = fopen("C:/path/to/somewhere/NUL", "r" );
if ( fp != NULL ) {
  fclose(fp);
  // directory exists
}

[CommonTater]

G'day Tater.

Anduril had a hyperlink to the findfirstfile() way to do it - I was looking for something that used C, instead of the Windows API. That's what it sounded like the OP was looking for (and I was curious myself).

Is there a standard C way to do this, without using either the Windows API functions, or non-standard C?

Quick way to check with Pelles...
If it's listed under "Private #includes" in the help file, it's not standard C.
Also if the function name is prefixed with an underscore it's not standard C.
Finally.. Hit F1 on the highlighted function... each is clearly marked in the help file.

Standard C is completely unaware of directories and folders, since each OS has it's own bright ideas about how to handle them.