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Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)scandir.3 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD$ 30.\" 31.Dd August 23, 2022 32.Dt SCANDIR 3 33.Os 34.Sh NAME 35.Nm scandir , 36.Nm scandirat , 37.Nm scandir_b , 38.Nm alphasort , 39.Nm versionsort 40.Nd scan a directory 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In dirent.h 45.Ft int 46.Fo scandir 47.Fa "const char *dirname" 48.Fa "struct dirent ***namelist" 49.Fa "int \*(lp*select\*(rp\*(lpconst struct dirent *\*(rp" 50.Fa "int \*(lp*compar\*(rp\*(lpconst struct dirent **, const struct dirent **\*(rp" 51.Fc 52.Ft 53.Fo scandirat 54.Fa int dirfd 55.Fa "const char *dirname" 56.Fa "struct dirent ***namelist" 57.Fa "int \*(lp*select\*(rp\*(lpconst struct dirent *\*(rp" 58.Fa "int \*(lp*compar\*(rp\*(lpconst struct dirent **, const struct dirent **\*(rp" 59.Fc 60.Ft int 61.Fo scandir_b 62.Fa "const char *dirname" 63.Fa "struct dirent ***namelist" 64.Fa "int \*(lp*select\^(rp\*(lpconst struct dirent *\*(rp" 65.Fa "int \*(lp^compar\*(rp\*(lpconst struct dirent **, const struct dirent **\*(rp" 66.Fc 67.Ft int 68.Fn alphasort "const struct dirent **d1" "const struct dirent **d2" 69.Ft int 70.Fn versionsort "const struct dirent **d1" "const struct dirent **d2" 71.Sh DESCRIPTION 72The 73.Fn scandir 74function 75reads the directory 76.Fa dirname 77and builds an array of pointers to directory 78entries using 79.Xr malloc 3 . 80It returns the number of entries in the array. 81A pointer to the array of directory entries is stored in the location 82referenced by 83.Fa namelist . 84.Pp 85The 86.Fa select 87argument is a pointer to a user supplied subroutine which is called by 88.Fn scandir 89to select which entries are to be included in the array. 90The select routine is passed a 91pointer to a directory entry and should return a non-zero 92value if the directory entry is to be included in the array. 93If 94.Fa select 95is null, then all the directory entries will be included. 96.Pp 97The 98.Fa compar 99argument is a pointer to a user supplied subroutine which is passed to 100.Xr qsort 3 101to sort the completed array. 102If this pointer is null, the array is not sorted. 103.Pp 104The 105.Fn alphasort 106function 107is a routine which can be used for the 108.Fa compar 109argument to sort the array alphabetically using 110.Xr strcoll 3 . 111.Pp 112The 113.Fn versionsort 114function is a routine which can be used for the 115.Fa compar 116argument to sort the array naturally using 117.Xr strverscmp 3 . 118.Pp 119The memory allocated for the array can be deallocated with 120.Xr free 3 , 121by freeing each pointer in the array and then the array itself. 122.Pp 123The 124.Fn scandirat 125function is similar to 126.Fn scandir , 127but takes an additional 128.Fa dirfd 129argument. 130If the supplied 131.Fa dirname 132is absolute, the function's behavior is identical to that of 133.Fn scandir , 134the 135.Fa dirfd 136argument is unused. 137If 138.Fa dirname 139is relative, 140.Fa dirfd 141must be a valid file descriptor referencing a directory, in 142which case the 143.Fa dirname 144lookup is performed relative to the directory referenced by 145.Fa dirfd . 146If 147.Fa dirfd 148has the special value 149.Va AT_FDCWD , 150then the current process directory is used as the base for 151relative lookups. 152See 153.Xr openat 2 154for additional details. 155.Pp 156The 157.Fn scandir_b 158function behaves in the same way as 159.Fn scandir , 160but takes blocks as arguments instead of function pointers and calls 161.Fn qsort_b 162rather than 163.Fn qsort . 164.Sh DIAGNOSTICS 165Returns \-1 if the directory cannot be opened for reading or if 166.Xr malloc 3 167cannot allocate enough memory to hold all the data structures. 168.Sh SEE ALSO 169.Xr openat 2 , 170.Xr directory 3 , 171.Xr malloc 3 , 172.Xr qsort 3 , 173.Xr strcoll 3 , 174.Xr strverscmp 3 , 175.Xr dir 5 176.Sh STANDARDS 177The 178.Fn versionsort 179function is a GNU extension and conforms to no standard. 180.Sh HISTORY 181The 182.Fn scandir 183and 184.Fn alphasort 185functions appeared in 186.Bx 4.2 . 187The 188.Fn scandirat 189and 190.Fn 191versionsort 192functions were added in 193.Fx 14.0 . 194