I'm writing a program to check if something is a file or is a directory. Is there a better way to do it than this?
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
int isFile(const char* name)
{
DIR* directory = opendir(name);
if(directory != NULL)
{
closedir(directory);
return 0;
}
if(errno == ENOTDIR)
{
return 1;
}
return -1;
}
int main(void)
{
const char* file = "./testFile";
const char* directory = "./";
printf("Is %s a file? %s.\n", file,
((isFile(file) == 1) ? "Yes" : "No"));
printf("Is %s a directory? %s.\n", directory,
((isFile(directory) == 0) ? "Yes" : "No"));
return 0;
}
You can call the stat() function and use the S_ISREG() macro on the st_mode field of the stat structure in order to determine if your path points to a regular file:
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
int is_regular_file(const char *path)
{
struct stat path_stat;
stat(path, &path_stat);
return S_ISREG(path_stat.st_mode);
}
Note that there are other file types besides regular and directory, like devices, pipes, symbolic links, sockets, etc. You might want to take those into account.
Normally you want to perform this check atomically with using the result, so stat() is useless. Instead, open() the file read-only first and use fstat(). If it's a directory, you can then use fdopendir()
to read it. Or you can try opening it for writing to begin with, and the open will fail if it's a directory. Some systems (POSIX 2008, Linux) also have an O_DIRECTORY extension to open which makes the call fail if the name is not a directory.
Your method with opendir() is also good if you want a directory, but you should not close it afterwards; you should go ahead and use it.
Use the S_ISDIRmacro:
int isDirectory(const char *path) {
struct stat statbuf;
if (stat(path, &statbuf) != 0)
return 0;
return S_ISDIR(statbuf.st_mode);
}
Yes, there is better. Check the stat or the fstat function
Source: Stackoverflow.com