.TH "Filename" 3o 2023-09-18 OCamldoc "OCaml library"
.SH NAME
Filename \- Operations on file names.
.SH Module
Module   Filename
.SH Documentation
.sp
Module
.BI "Filename"
 : 
.B sig end

.sp
Operations on file names\&.

.sp

.sp
.sp

.I val current_dir_name 
: 
.B string
.sp
The conventional name for the current directory (e\&.g\&. 
.ft B
\&.
.ft R
in Unix)\&.

.sp

.I val parent_dir_name 
: 
.B string
.sp
The conventional name for the parent of the current directory
(e\&.g\&. 
.ft B
\&.\&.
.ft R
in Unix)\&.

.sp

.I val dir_sep 
: 
.B string
.sp
The directory separator (e\&.g\&. 
.ft B
/
.ft R
in Unix)\&.

.sp
.B "Since"
3.11.2

.sp

.I val concat 
: 
.B string -> string -> string
.sp

.ft B
concat dir file
.ft R
returns a file name that designates file
.ft B
file
.ft R
in directory 
.ft B
dir
.ft R
\&.

.sp

.I val is_relative 
: 
.B string -> bool
.sp
Return 
.ft B
true
.ft R
if the file name is relative to the current
directory, 
.ft B
false
.ft R
if it is absolute (i\&.e\&. in Unix, starts
with 
.ft B
/
.ft R
)\&.

.sp

.I val is_implicit 
: 
.B string -> bool
.sp
Return 
.ft B
true
.ft R
if the file name is relative and does not start
with an explicit reference to the current directory (
.ft B
\&./
.ft R
or
.ft B
\&.\&./
.ft R
in Unix), 
.ft B
false
.ft R
if it starts with an explicit reference
to the root directory or the current directory\&.

.sp

.I val check_suffix 
: 
.B string -> string -> bool
.sp

.ft B
check_suffix name suff
.ft R
returns 
.ft B
true
.ft R
if the filename 
.ft B
name
.ft R
ends with the suffix 
.ft B
suff
.ft R
\&.
.sp
Under Windows ports (including Cygwin), comparison is
case\-insensitive, relying on 
.ft B
String\&.lowercase_ascii
.ft R
\&.  Note that
this does not match exactly the interpretation of case\-insensitive
filename equivalence from Windows\&.

.sp

.I val chop_suffix 
: 
.B string -> string -> string
.sp

.ft B
chop_suffix name suff
.ft R
removes the suffix 
.ft B
suff
.ft R
from
the filename 
.ft B
name
.ft R
\&.

.sp
.B "Raises Invalid_argument"
if 
.ft B
name
.ft R
does not end with the suffix 
.ft B
suff
.ft R
\&.

.sp

.I val chop_suffix_opt 
: 
.B suffix:string -> string -> string option
.sp

.ft B
chop_suffix_opt ~suffix filename
.ft R
removes the suffix from
the 
.ft B
filename
.ft R
if possible, or returns 
.ft B
None
.ft R
if the
filename does not end with the suffix\&.
.sp
Under Windows ports (including Cygwin), comparison is
case\-insensitive, relying on 
.ft B
String\&.lowercase_ascii
.ft R
\&.  Note that
this does not match exactly the interpretation of case\-insensitive
filename equivalence from Windows\&.

.sp
.B "Since"
4.08

.sp

.I val extension 
: 
.B string -> string
.sp

.ft B
extension name
.ft R
is the shortest suffix 
.ft B
ext
.ft R
of 
.ft B
name0
.ft R
where:
.sp
.sp
\-
.ft B
name0
.ft R
is the longest suffix of 
.ft B
name
.ft R
that does not
contain a directory separator;
.sp
\-
.ft B
ext
.ft R
starts with a period;
.sp
\-
.ft B
ext
.ft R
is preceded by at least one non\-period character
in 
.ft B
name0
.ft R
\&.

If such a suffix does not exist, 
.ft B
extension name
.ft R
is the empty
string\&.

.sp
.B "Since"
4.04

.sp

.I val remove_extension 
: 
.B string -> string
.sp
Return the given file name without its extension, as defined
in 
.ft B
Filename\&.extension
.ft R
\&. If the extension is empty, the function
returns the given file name\&.
.sp
The following invariant holds for any file name 
.ft B
s
.ft R
:
.sp

.ft B
remove_extension s ^ extension s = s
.ft R


.sp
.B "Since"
4.04

.sp

.I val chop_extension 
: 
.B string -> string
.sp
Same as 
.ft B
Filename\&.remove_extension
.ft R
, but raise 
.ft B
Invalid_argument
.ft R
if the given name has an empty extension\&.

.sp

.I val basename 
: 
.B string -> string
.sp
Split a file name into directory name / base file name\&.
If 
.ft B
name
.ft R
is a valid file name, then 
.ft B
concat (dirname name) (basename name)
.ft R
returns a file name which is equivalent to 
.ft B
name
.ft R
\&. Moreover,
after setting the current directory to 
.ft B
dirname name
.ft R
(with 
.ft B
Sys\&.chdir
.ft R
),
references to 
.ft B
basename name
.ft R
(which is a relative file name)
designate the same file as 
.ft B
name
.ft R
before the call to 
.ft B
Sys\&.chdir
.ft R
\&.
.sp
This function conforms to the specification of POSIX\&.1\-2008 for the
.ft B
basename
.ft R
utility\&.

.sp

.I val dirname 
: 
.B string -> string
.sp
See 
.ft B
Filename\&.basename
.ft R
\&.
This function conforms to the specification of POSIX\&.1\-2008 for the
.ft B
dirname
.ft R
utility\&.

.sp

.I val null 
: 
.B string
.sp

.ft B
null
.ft R
is 
.ft B
"/dev/null"
.ft R
on POSIX and 
.ft B
"NUL"
.ft R
on Windows\&. It represents a
file on the OS that discards all writes and returns end of file on reads\&.

.sp
.B "Since"
4.10.0

.sp

.I val temp_file 
: 
.B ?temp_dir:string -> string -> string -> string
.sp

.ft B
temp_file prefix suffix
.ft R
returns the name of a
fresh temporary file in the temporary directory\&.
The base name of the temporary file is formed by concatenating
.ft B
prefix
.ft R
, then a suitably chosen integer number, then 
.ft B
suffix
.ft R
\&.
The optional argument 
.ft B
temp_dir
.ft R
indicates the temporary directory
to use, defaulting to the current result of 
.ft B
Filename\&.get_temp_dir_name
.ft R
\&.
The temporary file is created empty, with permissions 
.ft B
0o600
.ft R
(readable and writable only by the file owner)\&.  The file is
guaranteed to be different from any other file that existed when
.ft B
temp_file
.ft R
was called\&.

.sp
.B "Before3.11.2"
no ?temp_dir optional argument


.sp
.B "Raises Sys_error"
if the file could not be created\&.

.sp

.I val open_temp_file 
: 
.B ?mode:open_flag list ->
.B   ?perms:int ->
.B   ?temp_dir:string -> string -> string -> string * out_channel
.sp
Same as 
.ft B
Filename\&.temp_file
.ft R
, but returns both the name of a fresh
temporary file, and an output channel opened (atomically) on
this file\&.  This function is more secure than 
.ft B
temp_file
.ft R
: there
is no risk that the temporary file will be modified (e\&.g\&. replaced
by a symbolic link) before the program opens it\&.  The optional argument
.ft B
mode
.ft R
is a list of additional flags to control the opening of the file\&.
It can contain one or several of 
.ft B
Open_append
.ft R
, 
.ft B
Open_binary
.ft R
,
and 
.ft B
Open_text
.ft R
\&.  The default is 
.ft B
[Open_text]
.ft R
(open in text mode)\&. The
file is created with permissions 
.ft B
perms
.ft R
(defaults to readable and
writable only by the file owner, 
.ft B
0o600
.ft R
)\&.

.sp
.B "Before4.03.0"
no ?perms optional argument


.sp
.B "Before3.11.2"
no ?temp_dir optional argument


.sp
.B "Raises Sys_error"
if the file could not be opened\&.

.sp

.I val get_temp_dir_name 
: 
.B unit -> string
.sp
The name of the temporary directory:
Under Unix, the value of the 
.ft B
TMPDIR
.ft R
environment variable, or "/tmp"
if the variable is not set\&.
Under Windows, the value of the 
.ft B
TEMP
.ft R
environment variable, or "\&."
if the variable is not set\&.
The temporary directory can be changed with 
.ft B
Filename\&.set_temp_dir_name
.ft R
\&.

.sp
.B "Since"
4.00.0

.sp

.I val set_temp_dir_name 
: 
.B string -> unit
.sp
Change the temporary directory returned by 
.ft B
Filename\&.get_temp_dir_name
.ft R
and used by 
.ft B
Filename\&.temp_file
.ft R
and 
.ft B
Filename\&.open_temp_file
.ft R
\&.

.sp
.B "Since"
4.00.0

.sp

.I val temp_dir_name 
: 
.B string
.sp
.B "Deprecated."
You should use 
.ft B
Filename\&.get_temp_dir_name
.ft R
instead\&.

.sp
The name of the initial temporary directory:
Under Unix, the value of the 
.ft B
TMPDIR
.ft R
environment variable, or "/tmp"
if the variable is not set\&.
Under Windows, the value of the 
.ft B
TEMP
.ft R
environment variable, or "\&."
if the variable is not set\&.

.sp
.B "Since"
3.09.1

.sp

.I val quote 
: 
.B string -> string
.sp
Return a quoted version of a file name, suitable for use as
one argument in a command line, escaping all meta\-characters\&.
Warning: under Windows, the output is only suitable for use
with programs that follow the standard Windows quoting
conventions\&.

.sp

.I val quote_command 
: 
.B string ->
.B   ?stdin:string -> ?stdout:string -> ?stderr:string -> string list -> string
.sp

.ft B
quote_command cmd args
.ft R
returns a quoted command line, suitable
for use as an argument to 
.ft B
Sys\&.command
.ft R
, 
.ft B
Unix\&.system
.ft R
, and the
.ft B
Unix\&.open_process
.ft R
functions\&.
.sp
The string 
.ft B
cmd
.ft R
is the command to call\&.  The list 
.ft B
args
.ft R
is
the list of arguments to pass to this command\&.  It can be empty\&.
.sp
The optional arguments 
.ft B
?stdin
.ft R
and 
.ft B
?stdout
.ft R
and 
.ft B
?stderr
.ft R
are
file names used to redirect the standard input, the standard
output, or the standard error of the command\&.
If 
.ft B
~stdin:f
.ft R
is given, a redirection 
.ft B
< f
.ft R
is performed and the
standard input of the command reads from file 
.ft B
f
.ft R
\&.
If 
.ft B
~stdout:f
.ft R
is given, a redirection 
.ft B
> f
.ft R
is performed and the
standard output of the command is written to file 
.ft B
f
.ft R
\&.
If 
.ft B
~stderr:f
.ft R
is given, a redirection 
.ft B
2> f
.ft R
is performed and the
standard error of the command is written to file 
.ft B
f
.ft R
\&.
If both 
.ft B
~stdout:f
.ft R
and 
.ft B
~stderr:f
.ft R
are given, with the exact
same file name 
.ft B
f
.ft R
, a 
.ft B
2>&1
.ft R
redirection is performed so that the
standard output and the standard error of the command are interleaved
and redirected to the same file 
.ft B
f
.ft R
\&.
.sp
Under Unix and Cygwin, the command, the arguments, and the redirections
if any are quoted using 
.ft B
Filename\&.quote
.ft R
, then concatenated\&.
Under Win32, additional quoting is performed as required by the
.ft B
cmd\&.exe
.ft R
shell that is called by 
.ft B
Sys\&.command
.ft R
\&.

.sp
.B "Since"
4.10.0

.sp
.B "Raises Failure"
if the command cannot be escaped on the current platform\&.

.sp