Man Pages

---

Back to Software Index  Manpage Top Level

Name

Synopsis

#include <dirent.h>
int scandir(const char *dirp, struct dirent ***namelist,int (*filter)(const
struct dirent *),int (*compar)(const struct dirent **, const struct dirent
**));
int alphasort(const struct dirent **a, const struct dirent **b);
int versionsort(const struct dirent **a, const struct dirent **b);#include
<fcntl.h>          /* Definition of AT_* constants */#include <dirent.h>

int (*filter)(const struct dirent *),int (*compar)(const struct dirent
**, const struct dirent **));

Feature Test Macro Requirements for glibc (see feature_test_macros(7) ):

scandir(), alphasort():

_BSD_SOURCE || _SVID_SOURCE
|| /* Since glibc 2.10: */

(_POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700)

versionsort(): _GNU_SOURCE

scandirat(): _GNU_SOURCE

Description

The alphasort() and versionsort() functions can be used as the comparison function compar(). The former sorts directory entries using strcoll(3) , the latter using strverscmp(3) on the strings (*a)->d_name and (*b)->d_name.

scandirat()

If the pathname given in dirp is relative, then it is interpreted relative to the directory referred to by the file descriptor dirfd (rather than relative to the current working directory of the calling process, as is done by scandir() for a relative pathname).

If dirp is relative and dirfd is the special value AT_FDCWD, then dirp is interpreted relative to the current working directory of the calling process (like scandir()).

If dirp is absolute, then dirfd is ignored.

See openat(2) for an explanation of the need for scandirat().

Return Value

The alphasort() and versionsort() functions return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.

Errors

ENOENT

The path in dirp does not exist.

ENOMEM

Insufficient memory to complete the operation.

ENOTDIR

The path in dirp is not a directory.

The following additional errors can occur for scandirat():

EBADF

dirfd is not a valid file descriptor.

ENOTDIR

dirp is a relative path and dirfd is a file descriptor referring to a file other than a directory.

Versions

scandirat() was added to glibc in version 2.15.

Conforming to

versionsort() and scandirat() are GNU extensions.

Notes

Example

#define _SVID_SOURCE
/* print files in current directory in reverse order */
#include <dirent.h>
int
main(void)
{
    struct dirent **namelist;
    int n;
    n = scandir(".", &namelist, NULL, alphasort);
    if (n < 0)
        perror("scandir");
    else {
        while (n--) {
            printf("%s\n", namelist[n]->d_name);
            free(namelist[n]);
        }
        free(namelist);
    }
}

See Also

Colophon

Table of Contents

• Name
• Synopsis
• Description
• scandirat()
• Return Value
• Errors
• Versions
• Conforming to
• Notes
• Example
• See Also
• Colophon