opendir() returns null but errno is zero

Elkvis · 12-16-2008, 12:37 PM

I'm having a problem with some code I'm writing on linux to list files in a directory using opendir/readdir, where opendir is returning NULL, but it's not setting errno to a useful value. I know for a fact that the directory I'm attempting to open exists, is a directory, I have access to it, there are not too many descriptors in use, there are not too many files open, and there is plenty of memory available. I'm really confused about this.

matsp · 12-16-2008, 12:50 PM

Perhaps posting the relevant code would help here... Sometimes someone else will spot the simple mistake that the person who wrote the code hasn't spotted.

--
Mats

Elkvis · 12-16-2008, 01:16 PM

this was the problem:

Code:

DIR* d = NULL;
d = opendir("mydir");
if (d == NULL);
{
  switch (errno)
  {
    // print errno to screen here and report the error
  }
}

stupid mistake.

12-16-2008, 12:37 PM	#1
Elkvis Registered User Join Date: Oct 2006 Posts: 298	opendir() returns null but errno is zero I'm having a problem with some code I'm writing on linux to list files in a directory using opendir/readdir, where opendir is returning NULL, but it's not setting errno to a useful value. I know for a fact that the directory I'm attempting to open exists, is a directory, I have access to it, there are not too many descriptors in use, there are not too many files open, and there is plenty of memory available. I'm really confused about this.
Elkvis is offline

12-16-2008, 12:50 PM	#2
matsp Kernel hacker Join Date: Jul 2007 Location: Farncombe, Surrey, England Posts: 15,686	Perhaps posting the relevant code would help here... Sometimes someone else will spot the simple mistake that the person who wrote the code hasn't spotted. -- Mats __________________ Compilers can produce warnings - make the compiler programmers happy: Use them! Please don't PM me for help - and no, I don't do help over instant messengers.
matsp is offline

12-16-2008, 01:16 PM	#3
Elkvis Registered User Join Date: Oct 2006 Posts: 298	this was the problem: Code: DIR* d = NULL; d = opendir("mydir"); if (d == NULL); { switch (errno) { // print errno to screen here and report the error } } stupid mistake.
Elkvis is offline

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