cp_files Module Reference

Utility routines to open and close files. More...

Functions/Subroutines
subroutine, public	close_file (unit_number, file_status)
	Closes an open file given by its logical unit number.
subroutine, public	open_file (file_name, unit_number, file_status, file_form, file_action, file_position, file_pad, file_access, debug)
	Opens a file and returns its logical unit number.
logical function, public	file_exists (file_name)
	Checks if a file exists, considering also the file discovery mechanism.
character(len=default_path_length) function, public	discover_file (file_name)
	Searches for a file in the current directory and then in the data directory.
character(len=default_path_length) function, public	get_data_dir ()
	Returns path of data directory if set, otherwise an empty string.
character(len=default_path_length) function, public	join_paths (path1, path2)
	Joins two file paths, inserting '/' as needed.

Detailed Description

Utility routines to open and close files.

History

• Creation CP2K_WORKSHOP 1.0 TEAM
• Revised (18.02.2011, MK)
• Enhanced error checking (22.02.2011, MK)
• Preconnected units removed (03.10.2026, MK)

Note

Positive unit numbers are used instead of OPEN(NEWUNIT=...), because NEWUNIT returns negative numbers and CP2K treats a unit number > 0 as "output enabled". open_file is thread-safe: finding a free unit and connecting the file are done within the OpenMP critical region cp_files_connect. Concurrent use of the same unit (I/O, REWIND, close_file) must be avoided by the caller.

Author

Matthias Krack (MK)

Function/Subroutine Documentation

close_file()

subroutine, public cp_files::close_file	(	integer, intent(in)	unit_number,
		character(len=*), intent(in), optional	file_status )

Closes an open file given by its logical unit number.

Parameters

unit_number	Logical unit number of the file to be closed
file_status	File status after closing: KEEP or DELETE (default: KEEP for named, DELETE for unnamed SCRATCH files)

Author

Matthias Krack (MK)

Note

The program is aborted, if the unit is one of the default units (stdin, stdout, stderr). A unit which is not open is ignored silently.

Definition at line 62 of file cp_files.F.

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open_file()

subroutine, public cp_files::open_file	(	character(len=*), intent(in), optional	file_name,
		integer, intent(out)	unit_number,
		character(len=*), intent(in), optional	file_status,
		character(len=*), intent(in), optional	file_form,
		character(len=*), intent(in), optional	file_action,
		character(len=*), intent(in), optional	file_position,
		character(len=*), intent(in), optional	file_pad,
		character(len=*), intent(in), optional	file_access,
		logical, intent(in), optional	debug )

Opens a file and returns its logical unit number.

Parameters

file_name	File name; must be omitted for an anonymous SCRATCH file
unit_number	Logical unit number of the opened file
file_status	Fortran file status OLD, NEW, REPLACE, UNKNOWN, or SCRATCH for an anonymous temporary file (default: OLD)
file_form	FORMATTED or UNFORMATTED (default: FORMATTED)
file_action	READ, WRITE, or READWRITE (default: WRITE for STATUS=NEW, REPLACE, and SCRATCH, otherwise READ)
file_position	ASIS, REWIND, or APPEND (default: REWIND)
file_pad	YES or NO (default: YES); only allowed for FORMATTED files
file_access	SEQUENTIAL or STREAM (default: SEQUENTIAL); DIRECT is not supported
debug	Print the connection properties to the default output unit

Author

Matthias Krack (MK)

Note

- If the file is already open, its unit number is returned and no new connection is made. ACTION, FORM, and ACCESS must match the existing connection; with POSITION=REWIND the file is rewound.

• For STATUS=OLD and ACTION=READ, the file is also looked up in the data directory (see discover_file). Files opened for writing are never taken from there.
• Any error aborts the program; there is no IOSTAT return.

Definition at line 194 of file cp_files.F.

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file_exists()

logical function, public cp_files::file_exists

(

character(len=*), intent(in)

file_name

)

Checks if a file exists, considering also the file discovery mechanism.

Parameters

file_name

Name of the file

Returns

True, if the file exists in the current or the data directory

Author

Ole Schuett

Definition at line 516 of file cp_files.F.

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discover_file()

character(len=default_path_length) function, public cp_files::discover_file

(

character(len=*), intent(in)

file_name

)

Searches for a file in the current directory and then in the data directory.

Parameters

file_name

Name of the file

Returns

File name as given, if it exists, otherwise its path in the data directory, if it exists there, else the file name stripped of blanks

Author

Ole Schuett

Definition at line 536 of file cp_files.F.

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get_data_dir()

character(len=default_path_length) function, public cp_files::get_data_dir

Returns path of data directory if set, otherwise an empty string.

Returns

Path of the data directory or an empty string

Author

Ole Schuett

Definition at line 573 of file cp_files.F.

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join_paths()

character(len=default_path_length) function, public cp_files::join_paths	(	character(len=*), intent(in)	path1,
		character(len=*), intent(in)	path2 )

Joins two file paths, inserting '/' as needed.

Parameters

path1	Leading path, e.g. a directory
path2	Trailing path; returned unchanged if it is an absolute path

Returns

Joined path; the program is aborted, if it exceeds default_path_length

Author

Ole Schuett

Definition at line 607 of file cp_files.F.

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