Thread: Segmentation fault problem

Hi.

I`m struggling with the following function for almost 2 hours now and I can`t figure out what is the problem with it, maybe you can help me.

The function lists the files and folders in a specified folder, and loads the result into a FileData array.

Code:

typedef struct
{
	char *fileName;
	int isFile;
} FileData;

FileData **fs_listFiles(const char *path)
{
	DIR *dir;
	struct dirent *ent;
	FileData **fd;
	int i;

	dir = opendir (path);

	if (dir != NULL)
	{
		while ((ent = readdir (dir)) != NULL)
		{
			fd[i] 				= (FileData **)malloc(sizeof(FileData*));
			fd[i]->fileName = ent->d_name;

			printf("%s\n",fd[i]->fileName);

			i++;
		}

		closedir (dir);
		return fd;
	}

	return NULL;
}

When I run this piece of code, it breaks with segmentation faul at the fd[i]->fileName = ent->d_name; part. I also tried to use realloc like this: fd = (FileData **)realloc((void *)fd, sizeof(FileData*)*(i+1)); but still no luck.

If i print the size of the allocated memory for the fd variable it doesnt break, and the size itself seems to be ok.

Can anybody help me?

Thank you.

First of all, thank you for you quick responses.

I`m sorry, at the fd[i] = (FileData **)malloc(sizeof(FileData*)); part the cast supposed to be just (FileData *) when i copied the code here i changed the realloc to malloc, and the cast remained unchanged.

Anyway, i tried what tabstop suggested, first realloced the array, and malloced the struct on the specified index, and now it works as it supposed to.

Thank you again for your help.

Originally Posted by raczzoli

Code:

		while ((ent = readdir (dir)) != NULL)
		{
			fd[i] = (FileData **)malloc(sizeof(FileData*));
			fd[i]->fileName = ent->d_name;

Firt you can't assign strings across the equals sign in C... all you're doing it assigning a pointer that is wiped out on the next iteration of your loop.

You need to actually copy the filename into your struct...

Code:

typedef struct
{
	char fileName[256];
	int isFile;
} FileData;


// then

strcpy(fd[i]->fileName, ent->d_name);