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Stephen KairysFlag for United States of America

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C function to determine if a directory exists

Using C (not C++):

I have often used the C function access() to determine if a file exists e.g

if (!access(filename, F_OK))
   printf("File exists);
  printf("File does NOT exist\n");

For my current purposes, I need to be able to tell if a particular SUBDIRECTORY exists.
e..g if I have a subdir "STEVE", and pass "STEVE" to access() it will return 0, but I need to be able to tell if "STEVE" is a subdir, rather than a file.  Is there a function that can help me out?


Avatar of Kent Olsen
Kent Olsen
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Hi Steve,

One of the stat() functions should do nicely.


#include <sys\stat.h>
#include <stdio.h>
#include <time.h>
int main(void)
   struct stat statbuf;
   int    handle;

//  int stat(const char *path, struct stat *statbuf); 
   stat ("c:\\mypath\\dirname", &statbuf);

   if (statbuf.st_mode & S_S_IFDIR)

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Avatar of phoffric

you can use readdir and get the file stats: 

"The stat() function fills a struct stat structure with information about a specific file; if you've got a file descriptor instead of a file name, you can use the fstat() function instead."

•"S_ISDIR(mode) -- Is this a directory?"
•"S_ISREG(mode) -- Is this a regular file?"
Didn't see your post Kent while getting the link and excerpting from it.
Avatar of Stephen Kairys


Welk. I tried your code, but it seems that the identifier


is not included in my

even though stat() is prototyped in stat.h.
Any idea what I'm doing wrong?

Did you also try
•"S_ISDIR(mode) -- Is this a directory?"
In listing 5, for example, is the LOC:
     if( S_ISDIR( entryInfo.st_mode ) ) {
Or, just a typo: try S_IFDIR  instead.
S_ISDIR(mode) -- Is this a directory
Not sure I understand this. What is mode?
I see in sys\stat.h that
#define S_ISDIR( m )      (((m) & S_IFMT) == S_IFDIR)
is a macro, but not sure what to pass to it.
Look like both S_IFDIR and S_ISDIR exist in stat.h

#define S_IFDIR       0040000 /* directory */
#define S_ISDIR( m )      (((m) & S_IFMT) == S_IFDIR)

Still..need to know..what do I pass in as the parameter "mode"?
I see the two links you posted are from UNIX and Linux. Do they apply to WIndows/DOS 16-bit programming?
Avatar of Kent Olsen
Kent Olsen
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OK, I think I got it.

Just to be safe, I first use access() to determine if the file exists: Then I invoke stat...
Please do not assume this code is perfect. I did only cursory testing.

Thanks everyone!

Actually I defer to Kent. You don't need to include <sys\types.h>.  Points to be awaeded shortly. Thanks!
Thank you. Your solution had everything in one place so you get the points

phoffric: - As per the above, Kent got the points, but I still appreciate your help. If you feel that you should share in the points, feel free t respond; however, I won't be able to handle your request 'til at least next Thursday as I am going to be on a short vacation. Thanks for your efforts.
>> Do they apply to WIndows/DOS 16-bit programming
I didn't realize you were working in Windows/DOS 16-bit programming. And I don't have that product available to test, so I cannot be sure.

But, I tried the kdo's post in VS 2010 Express, and it works fine (with the typo corrected), so that is a good sign that it will work for you.

Since S_ISDIR is defined for you (it is not defined in sys\stat.h in VS 2010 Express), I think the below code should work for you since it works in Linux. However, you need to verify using your DOS-16 system.
if (statbuf.st_mode & S_IFDIR)  
   if( S_ISDIR( statbuf.st_mode ) )
      printf("S_ISDIR works in Linux\n");

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no problem w/ the points. Like I said, it was just a typo.
Thanks.  Anyone who reads this question should realize that I did not try it on the Linux or Unix but n 16-bit DOS running under windows.