Open directory using C

Question

I am accepting the path through command line input.

When I do

dir=opendir(args[1]);

it doesn\' t enter the loop...i.e dir==nu

Answer 1

Some feedback on the segment of code, though for the most part, it should work...

void main(int c,char **args)

• int main - the standard defines main as returning an int.
• c and args are typically named argc and argv, respectfully, but you are allowed to name them anything

...

{
DIR *dir;
struct dirent *dent;
char buffer[50];
strcpy(buffer,args[1]);

• You have a buffer overflow here: If args[1] is longer than 50 bytes, buffer will not be able to hold it, and you will write to memory that you shouldn't. There's no reason I can see to copy the buffer here, so you can sidestep these issues by just not using strcpy...

...

dir=opendir(buffer);   //this part

If this returning NULL, it can be for a few reasons:

• The directory didn't exist. (Did you type it right? Did it have a space in it, and you typed ./your_program my directory, which will fail, because it tries to opendir("my"))
• You lack permissions to the directory
• There's insufficient memory. (This is unlikely.)