CHMOD

Portability Function: Changes the access mode of a file.

Module: USE IFPORT

Syntax

result = CHMOD (name, mode)

name
(Input) Character*(*). Name of the file whose access mode is to be changed. Must have a single path.

mode
(Input) Character*(*). File permission: either Read, Write, or Execute. The mode parameter can be either symbolic or absolute. An absolute mode is specified with an octal number, consisting of any combination of the following permission bits ORed together:

Permission bit Description Action

4000 Set user ID on execution W*32, W*64: Ignored; never true
L*X, M*X: Settable

2000 Set group ID on execution W*32, W*64: Ignored; never true
L*X, M*X: Settable

1000 Sticky bit W*32, W*64: Ignored; never true
L*X, M*X: Settable

0400 Read by owner W*32, W*64: Ignored; always true
L*X, M*X: Settable

0200 Write by owner Settable

0100 Execute by owner W*32, W*64: Ignored; based on file name extension
L*X, M*X: Settable

0040, 0020, 0010 Read, Write, Execute by group W*32, W*64: Ignored; assumes owner permissions
L*X, M*X: Settable

0004, 0002, 0001 Read, Write, Execute by others W*32, W*64: Ignored; assumes owner permissions
L*X, M*X: Settable

Permission bit	Description	Action
4000	Set user ID on execution	W32, W64: Ignored; never true LX, MX: Settable
2000	Set group ID on execution	W32, W64: Ignored; never true LX, MX: Settable
1000	Sticky bit	W32, W64: Ignored; never true LX, MX: Settable
0400	Read by owner	W32, W64: Ignored; always true LX, MX: Settable
0200	Write by owner	Settable
0100	Execute by owner	W32, W64: Ignored; based on file name extension LX, MX: Settable
0040, 0020, 0010	Read, Write, Execute by group	W32, W64: Ignored; assumes owner permissions LX, MX: Settable
0004, 0002, 0001	Read, Write, Execute by others	W32, W64: Ignored; assumes owner permissions LX, MX: Settable

The following regular expression represents a symbolic mode:

[ugoa]*[+-=] [rwxXst]*

"[ugoa]*" is ignored on Windows* systems. On Linux* and Mac OS* systems, a combination of the letters "ugoa" control which users' access to the file will be changed:

u	The user who owns the file
g	Other users in the group that owns the file
o	Other users not in the group that owns the file
a	All users

"[+ - =]" indicates the operation to carry out:

+	Add the permission
-	Remove the permission
=	Absolutely set the permission

"[rwxXst]*" indicates the permission to add, subtract, or set. On Windows systems, only "w" is significant and affects write permission; all other letters are ignored. On Linux and Mac OS systems, all letters are significant.

Results

The result type is INTEGER(4). It is zero if the mode was changed successfully; otherwise, an error code. Possible error codes are:

ENOENT: The specified file was not found.
EINVAL: The mode argument is invalid.
EPERM: Permission denied; the file's mode cannot be changed.

Compatibility

CONSOLE STANDARD GRAPHICS QUICKWIN GRAPHICS WINDOWS DLL LIB

See Also

SETFILEACCESSQQ

Example

USE IFPORT
integer(4) I,Istatus
I = ACCESS ("DATAFILE.TXT", "w")
if (i) then
   ISTATUS = CHMOD ("datafile.txt", "[+w]")
end if
I = ACCESS ("DATAFILE.TXT","w")
print *, i