Path

Definition

A modern, portable Fortran module for path manipulation and basic directory operations. This module provides a clean interface for working with file system paths in a platform-independent way. It correctly handles both Unix ('/') and Windows ('\') path separators through conditional compilation and offers deferred-length character results for maximum flexibility.

The module builds upon the fpx_string module for string type support and provides overloads of key procedures to accept either intrinsic character(*) or type(string) arguments.

Features include:

• Detection of absolute and rooted paths
• Cross-platform path joining
• Extraction of directory and filename components
• Splitting paths into head/tail elements
• Retrieval and modification of the current working directory
• Support for both intrinsic CHARACTER and type(string) arguments
• Changing the current working directory (chdir)

Note

All path-returning functions return allocatable deferred-length characters.

The public generic join interface works with any combination of character and string.

Examples

character(:), allocatable :: p1, p2, full
 
p1 = '/home/user/docs'
p2 = 'report.pdf'
full = join(p1, p2)                ! => '/home/user/docs/report.pdf'
 
print *, is_absolute(full)         ! .true.  (on Unix)
print *, filename(full)            ! 'report'
print *, filename(full,.true.)     ! 'report.pdf'
print *, dirpath(full)             ! '/home/user/docs'

On Windows:

character(:), allocatable :: p
p = join('C:\Users', 'Alice', 'Documents')
! p == 'C:\Users\Alice\Documents'
print *, is_absolute(p)   ! .true.

Data Types
interface	join
	Join path components using the platform separator. More...

Methods

chdir()

subroutine, public chdir	(	character(*), intent(in)	path,
		integer, intent(out), optional	err )

Changes the current working directory. This is a thin wrapper around the underlying C runtime chdir() implementation.

Parameters

[in]	path	Directory to change to
[out]	err	Optional integer error code (0 = success, non-zero = failure) integer :: ierr call chdir('/tmp', ierr) if (ierr /= 0) stop 'Failed to change directory'

Definition at line 456 of file path.f90.

cwd()

character(:) function, allocatable, public cwd

Returns the current working directory as a deferred-length character string. Returns an empty string if the current directory cannot be determined.

Returns

res Current working directory

character(:), allocatable :: here
here = cwd()
print *, 'We are in: ', here

Definition at line 425 of file path.f90.

is_absolute()

pure logical function, public is_absolute

(

character(*), intent(in)

filepath

)

Returns .true. if the path is absolute. On Unix a path is absolute when it starts with '/'. On Windows a path is absolute when it starts with a drive letter followed by ':\C:\', 'd:/temp').

Parameters

[in]

filepath

Path to test

Returns

res .true. if filepath is absolute

print *, is_absolute('/home/user')   ! .true.  (Unix)
print *, is_absolute('C:\\Temp')     ! .true.  (Windows)
print *, is_absolute('docs/..')      ! .false.

Definition at line 166 of file path.f90.

is_rooted()

pure logical function, public is_rooted

(

character(*), intent(in)

filepath

)

Returns .true. if the path is rooted (starts with a separator) or is absolute. A rooted path begins with the platform separator ('\' on Windows, '/' elsewhere) even if it is not a full absolute path (e.g. '/temp' on Linux).

Parameters

[in]

filepath

Path to test

Returns

res .true. if filepath is rooted

Definition at line 188 of file path.f90.

join_character_character()

pure character(:) function, allocatable join_character_character	(	character(*), intent(in)	path1,
		character(*), intent(in)	path2 )

Implementation of join for character arguments.

The generic interface accepts any combination of intrinsic character(*) and string arguments.

Supported overloads:

• join(character, character)
• join(character, string)
• join(string, character)
• join(string, string)

Examples

character(:), allocatable :: p
 
p = join('/usr','bin')
! '/usr/bin'
 
p = join(string('/usr'),'local')
! '/usr/local'

Definition at line 246 of file path.f90.

join_character_string()

pure character(:) function, allocatable join_character_string	(	character(*), intent(in)	path1,
		type(string), intent(in)	path2 )

Implementation of join for character arguments.

The generic interface accepts any combination of intrinsic character(*) and string arguments.

Supported overloads:

• join(character, character)
• join(character, string)
• join(string, character)
• join(string, string)

Examples

character(:), allocatable :: p
 
p = join('/usr','bin')
! '/usr/bin'
 
p = join(string('/usr'),'local')
! '/usr/local'

Definition at line 264 of file path.f90.

join_string_character()

pure character(:) function, allocatable join_string_character	(	type(string), intent(in)	path1,
		character(*), intent(in)	path2 )

Implementation of join for character arguments.

The generic interface accepts any combination of intrinsic character(*) and string arguments.

Supported overloads:

• join(character, character)
• join(character, string)
• join(string, character)
• join(string, string)

Examples

character(:), allocatable :: p
 
p = join('/usr','bin')
! '/usr/bin'
 
p = join(string('/usr'),'local')
! '/usr/local'

Definition at line 282 of file path.f90.

join_string_string()

pure character(:) function, allocatable join_string_string	(	type(string), intent(in)	path1,
		type(string), intent(in)	path2 )

Implementation of join for character arguments.

The generic interface accepts any combination of intrinsic character(*) and string arguments.

Supported overloads:

• join(character, character)
• join(character, string)
• join(string, character)
• join(string, string)

Examples

character(:), allocatable :: p
 
p = join('/usr','bin')
! '/usr/bin'
 
p = join(string('/usr'),'local')
! '/usr/local'

Definition at line 300 of file path.f90.

split_path()

pure subroutine, public split_path	(	character(*), intent(in)	filepath,
		character(:), intent(out), allocatable	head,
		character(:), intent(out), allocatable	tail )

Splits a path into head (directory) and tail (basename) components. Special cases:

• Empty paths return ('.','')
• Root directories return ('/','')
• Trailing separators are ignored

  Parameters

  [in]	filepath	Input path
  [out]	head	Directory part (includes trailing separator when appropriate)
  [out]	tail	Base name part

Definition at line 363 of file path.f90.