Directory Related Calls in C Language
Here are the summary of the system calls to manipulate the directories.
| Function | Description | Returns |
|---|---|---|
| mkdir(const char * pathname, mode) | Create a dirctory | 0 if OK, -1 on error |
| rmdir(const char * pathname) | Delete a directory | 0 if OK, -1 on error |
| opendir(const char * pathname) | Open a directory | Pointer of DIR if OK, NULL on error |
| readdir(DIR * dp) | Read a directory | Pointer of dirent if OK, NULL at the end of directory or error |
| closedir(DIR * dp) | Close a directory | 0 if OK, -1 on error |
In *nix, we have a special data structure for a directory, namelyDIRanddirent.
DIRis a structure for directory streams, anddirenthas the following members:
ino_t d_ino: file serial numberchar d_name[]: Name of entry.
Example
In the following, we try to make use ofopendirandreaddirto traverse the directory, simulating a simplels.
/* listdir.c */
#include <stdio.h>
#include <dirent.h>
int main (int argc,char *argv[]) {
int total = 0;
DIR *pDir;
struct dirent *pDirent;
if (argc < 2) {
printf ("Missing out directory!\n");
return -1;
}
pDir = opendir (argv[1]);
if (pDir == NULL) {
printf ("Cannot open directory '%s'\n", argv[1]);
return 1;
}
while ((pDirent = readdir(pDir)) != NULL) {
printf ("[%s]\n", pDirent->d_name);
}
closedir (pDir);
return 0;
}
When you run the command `./listdir .',
The content of the current directory is printed.