CompareFilenames is an overloaded Integer function used to compare the specified file names to get their relative order for sorting operations. CompareFilenames provides implementations which accept String or PChar values (and their lengths) as arguments. The implementations are platform- and/or OS-specific; they consider whether the file system is case sensitive or when UTF-8 encoding is supported.

The return value indicates the relative order in a sort operation, and can contain the following values:

<0

Filename1 comes before Filename2

0

Filename1 and Filename2 to have the same value

>0

Filename1 comes after Filename2

CompareFilenamesIgnoreCase is an overloaded Integer function used to compare the specified file names to get their relative order in case-insensitive sorting operations. CompareFilenamesIgnoreCase provides alternate implementations which accept String or PChar values (and their lengths) as arguments. The implementations are platform- and/or OS-specific; they consider whether the file system is case sensitive, and when UTF-8 encoding is supported.

The return value indicates the relative order in a case-insensitive sort operation, and can contain the following values:

<0

Filename1 comes before Filename2

0

Filename1 and Filename2 to have the same value

>0

Filename1 comes after Filename2

CompareFileExt is an overloaded Integer function used to compare the file extension in Filename to the value in Ext.

FilenameM contains the file name with the extension compared in the routine.

Ext contains the file extension for the comparison. It may contain the '.' character, but it is not required and will be removed for the comparison.

CaseSensitive indicates whether case is used in the comparison. When CaseSensitive contains True, CompareStr is called to perform the comparison. Otherwise, UTF8CompareText is called to compare the values.

The return value indicates the order for the file name extension relative to the specified extension. It may contain one of the following values:

-1

Filename value has a lower sort order value than Ext

0

Filename and Ext have the same sort order values

1

Filename value has a higher sort order value than Ext

The return value is 1 if Filename does not contain a file extension.

The overloaded variant which omits the CaseSensitive argument defaults to the setting for the CaseInsensitiveFilenames compiler define on the platform. When defined, the CaseSensitive argument defaults to False. Otherwise, True is used in the parameter value.

CompareFilenameStarts is an Integer function used to compare the specified file names to determine their relative sort order. Arguments in Filename1 and Filename2 do not need to be the same length. When they have different lengths, the number of characters common to both are used in the comparison. CompareFilenameStarts calls CompareFileNames to perform the comparison, and get the return value for the function.

See CompareFilenames for more information about the numeric return value and its meaning.

CompareFilenamesP is an Integer function used to compare the specified file names to determine their relative sort order.

Filename1 and Filename2 are the PChar arguments containing the file names examined in the routine.

IgnoreCase indicates if upper- or lower-case differences are ignored in the file name comparison; the default value for the parameter is False (indicating that case differences are not ignored). For platforms where CaseInsensitiveFilenames is defined, the value in IgnoreCase defaults to True. When IgnoreCase is True, the UTF8CompareText function is called to perform a case-insensitive comparison of the specified file names. Otherwise, the ordinal byte values in the specified file names are compared until a difference is found, or the entire file name in Filename1 has been examined.

If either Filename1 or Filename2 are unassigned (contain Nil) or begin with a Null character (Decimal 0), the return value is set 0 (zero) and no additional actions are performed in the function. See CompareFilenames for more information about the numeric return value for the function and its meaning.

FilenameExtIs is a Boolean function used to determine if the file in the Filename parameter has the specified file extension in Ext.

Ext can contain the '.' (Period) character in the extension, but it is not required.

CaseSensitive indicates if case-sensitivity is used when comparing parameter values. When set to True, the comparison is limited to values in the ASCII character set. StrLComp or StrLIComp is called to compare the values in Filename to the values in Ext.

The return value is True when Filename uses the file extension in Ext. The return value is False for the following conditions:

• Filename is an empty string ('').
• Filename does not have a '.' character that marks the start of the file extension.
• The extension in Filename has a different length than Ext.
• Filename has a different file extension than Ext.

FilenameExtIn is a Boolean function used to determine if the file name in the Filename parameter uses one of the file extension in Exts.

Exts is an array type with the file extensions expected in the routine. Values in Exts can contain the '.' (Period) character in the extension, but it is not required.

CaseSensitive indicates if case-sensitivity is used when comparing the parameter values. When set to True, the comparison is limited to characters in the ASCII character set. StrLComp or StrLIComp is called to compare the value in Filename to the values in Exts.

The return value is True when Filename uses one the file extension in Exts. The return value is False when Filename is an empty string (''), does not include a '.' character that marks the start of the file extension, or does not use one of the values in Exts.

DirPathExists is a Boolean function which indicates if the specified directory name exists on the file system. DirectoryName can contain a trailing path delimiter, but it is removed in the function. DirPathExists calls DirectoryExistsUTF8 to get the return value.

DirectoryIsWritable is a Boolean function used to determine if the specified directory name is writable in the file system. The path name in DirectoryName must already exist on the local file system. The return value is False if a directory with the specified name does not exist.

The return value is True when a file can be added, deleted, or modified in the specified path. To get the return value, DirectoryIsWritable creates a temporary file in DirectoryName, adds content to it, and deletes the temporary file. DirectoryIsWritable calls the FileCreateUTF8, FileWrite, FileClose, and DeleteFileUTF8 routines to perform the file operations. The return value is True when FileWrite completes successfully.

ExtractFileNameOnly is a String function used to extract the base file name (without the file extension) from the value in AFilename. Path information, up to the last directory separator ('/' or '\') or device separator (':') character, in AFileName is ignored. The file extension, starting at the '.' character, is also omitted.

Processes characters in AFilename in reverse order to locate the '.' that starts the file extension. If a '.' character is not found, the process continues until a path or directory delimiter is found. The return value defaults to AFilename if a path or directory delimiter occurs before a '.' character.

FilenameIsAbsolute is a Boolean function used to determine if the value in TheFilename contains an absolute file path (and not a relative one). The implementation for FilenameIsAbsolute is platform- and/or OS-specific.

In UNIX-like environments, the FilenameIsUnixAbsolute function is used in the implementation. The return value is False if TheFilename is an empty string (''), or does not start with the directory separator for the environment.

On Windows, the FilenameIsWinAbsolute function is called in the implementation. FilenameIsWinAbsolute takes Device identifiers into consideration when examining the value in TheFilename. For example:

The return value is False if TheFilename (without the optional device identifier) is an empty string (''), or does not start with the directory separator for the environment.

FilenameIsWinAbsolute is a Boolean function used to determine if the value in TheFilename contains an absolute file path (and not a relative one).

On Windows, the FilenameIsWinAbsolute function is called in the implementation of FilenameIsAbsolute. FilenameIsWinAbsolute takes Device identifiers into consideration when examine the value in TheFilename. For example:

The return value is False if TheFilename (without the optional device identifier) is an empty string (''), or does not start with the directory separator for the environment.

FilenameIsUnixAbsolute is a Boolean function used to determine if the value in TheFilename contains an absolute file path (and not a relative one).

In UNIX-like environments, the FilenameIsUnixAbsolute function is used in the implementation of FilenameIsAbsolute. The return value is False if TheFilename is an empty string (''), or does not start with the directory separator for the environment.

ForceDirectory is a Boolean function which creates the specified directory if it does not already exist. ForceDirectory ensures that a trailing path delimiter exists in DirectoryName prior to checking the file system. Duplicate adjacent path delimiters (like '//foo//bar/foobar/' or '\\foo\\bar\foobar\') are removed prior to checking the directory path.

Each directory in the specified path is validated by calling DirPathExists. ForceDirectory calls CreateDirUTF8 if a directory does not exist, and may exit with a return value of False if directory creation is not successful.

The return value is True if all directories in the path information already exist, or are successfully created in the function.

CheckIfFileIsExecutable is a procedure used to examine the specified file name to see if it is executable. CheckIfFileIsExecutable is implemented for UNIX-like environments, and allows a process to better determine if the file can be executed on the platform or OS, and to get better error messages when it cannot.

CheckIfFileIsExecutable raises an exception with a specific message when the platform or OS facilities indicate it is necessary.

Use FileIsExecutable to determine of a file is executable without raising an exception.

CheckIfFileIsSymlink is a routine used to ensure that the file name specified in AFilename is a valid symbolic link on the local file system. It acts as an assert for the pre-condition.

The implementation for the routine is platform- or OS-specific. In general, all of the platforms raise an exception if the file name does not exist on the local file system of when the file name is not a symbolic link. The mechanism used to check for a symbolic link is platform-dependent.

For the Windows platform, the file name must be a link create using mklink on the local file system.

For UNIX-like platforms, the FpReadLink routine is called to examine the file name. The value from fpGetErrNo is used to get specific error information that can be used in the exception. For example:

ESysEAcces

Read access is denied for the symbolic link.

ESysENoEnt

A directory does not exist or is a dangling symbolic link.

ESysENotDir

A value in the file name is not a directory.

ESysENoMem

Insufficient memory to a access the symbolic link.

ESysELoopy

A circular reference was detected in the symbolic link.

Calling CheckIfFileIsSymlink on the Amiga platform will always result in an exception. Symbolic links are not supported on the Amiga platform.

FileIsExecutable is a Boolean function used to determine if the specified file name is executable. For UNIX-like environments, a combination of FpStat, FPS_ISREG, and FpAccess are used to get the return value. For the Windows environment, the value from FileExistsUTF8 is used as the return value. In short, the function is not really useful in a Windows environment.

FileIsSymlink is a Boolean function used to determine if the specified file name is a symbolic link on the local file system.

The implementation of FileIsSymlink is platform-specific. For UNIX-like environments, the FpReadLink function is used to determine if the symbolic link can be resolved to a physical file name in the local file system. For the Windows platform, FileGetAttrUTF8 is called to get and examine the file attributes for the specified file name. The file attributes must include the value FILE_ATTRIBUTE_REPARSE_POINT, and one of the Windows API values such as IO_REPARSE_TAG_SYMLINK or IO_REPARSE_TAG_MOUNT_POINT for the corresponding file handle. For the Amiga platform, FileIsSymLink always returns False.

FileIsHardLink is a Boolean function used to determine if the specified file name is represented by a file descriptor or handle on the local file system.

The implementation of FileIsHardLink is platform- or OS-specific. For UNIX-like environments, a file handle is retrieved by calling the FileOpenUTF8 function and passed to the FpFStat function to access the file information. For the Windows platform (excluding WinCE and Windows XP), the GetFileInformationByHandle Windows API routine is called to get information for the file handle. For the Amiga platform, FileIsHardLink always returns False.

The return value is False if a file handle could not be accessed for the specified file name or it is actually a symbolic link on the local file system.

FileIsReadable is a Boolean function which indicates if the specified file name is readable. For UNIX-like environments, FpAccess is used to get the return value. On Windows, the return value is the result from FileExistsUTF8. In short, the function is not really useful on the Windows platform where a suitable file attribute does not exist for the purpose.

FileIsWritable is a Boolean function which indicates if the specified file name is writable. For UNIX-like environments, FpAccess is used to get the return value. For Windows, FileGetAttrUTF8 is used to determine if faReadOnly is omitted from the attributes for the file.

FileIsText is a Boolean function used to determine if the specified file contains plain text content. The overloaded variant that includes the FileReadable argument is used to examine the content in the file.

FileIsText calls FileOpenUtf8 for the specified file name. The return value is False is the file handle contains feInvalidHandle.

FileIsText checks for (and skips) common Byte Order Marks, such as:

• UTF-8 BOM (Hex $EF $BB $BF)
• UCS-2LE BOM (Hex $FF $FE)
• UCS-2BE BOM (Hex $FE $FF)

Content in the file (up to 1024 characters) is checked to ensure that invalid Null and Control characters are not found in the file. The return value is True when the specified file name exists in the local file system, and does not contain Null or Control characters.

FilenameIsTrimmed is an overloaded Boolean function used to determine if the specified file name contains characters to remove or resolve before use. The variant which uses PChar values performs the comparison. The return value is False when the file name is a candidate for use of TrimFilename to remove whitespace or special characters.

Use TrimFilename to remove leading or trailing whitespace, duplicate directory separators, or relative path symbols.

ResolveDots is a String function used to convert relative path information in AFilename to an absolute path reference. A relative path includes characters like '.' (for current directory - not a file name extension) and '..' (parent directory). Duplicate path limiters ('\\' for Windows) ('//' for UNIX-like environments) are converted to a single instance of the PathDelimiter defined for the platform.

For Windows platforms, drive letter designations and delimiters like 'C:' are recognized. A path starting with the UNC naming convention ('\\?\') is not resolved in the method.

Windows-specific file system quirks handled in the routine include:

C:..

Not resolved, it is copied.

C:\..

Resolved to C:\

\\..

Resolved to \\

For UNIX-like environments, the resolved path may be invalid if it references the parent directory and the initial directory in the path is a symbolic link.

When AFilename ends with a relative path ('/.' or '/..'), an additional path delimiter is added to the return value.

If a relative path reference cannot be resolved for the local file system, the original path information is retained.

Macros found in the AFilename are retained if the relative path references a parent directory. For example:

CleanAndExpandFilename is a String function used to remove whitespace and to resolve special characters in the specified file name. CleanAndExpandFilename calls TrimFilename and ExpandFileNameUTF8 to get the return value for the function. The return value is the current directory when Filename contains an empty string ('').

CleanAndExpandDirectory is a String function used to remove whitespace and resolve special characters in the specified path. CleanAndExpandDirectory calls CleanAndExpandFilename to get the return value for the function. CleanAndExpandDirectory calls AppendPathDelim to ensure that a trailing path delimiter is included in the return value. The return value is the current directory when the specified path contains an empty string ('').

TrimAndExpandFilename is a String function used to remove whitespace and special characters in Filename, and to resolve the relative file path to the directory in BaseDir. TrimAndExpandFilename removes a trailing path delimiter in Filename, and calls ExpandFileNameUTF8 and TrimFilename to get the return value for the function.

The return value is an empty string ('') if Filename contains an empty string ('').

TrimAndExpandDirectory is a String function used to remove whitespace and special characters in the path information, and to resolve a relative path to the specified base directory.

TrimAndExpandDirectory calls ExpandFileNameUTF8 to resolve the relative path, and calls TrimFilename to get the return value for the function. The return value is an empty string ('') when TrimFilename returns an empty string ('').

CreateAbsolutePath is a String function used to get the absolute path to the file specified in the Filename argument. A relative path reference in Filename is resolved to the path in the BaseDir argument. The return value contains the fully-qualified absolute path to the specified file name.

When Filename is an empty string ('') or already uses an absolute path reference, the value in Filename is used as the return value.

For the Windows platform, a file name which starts with '\' (root directory on the current drive) is resolved to the drive letter and root directory in BaseDIr. For all other platforms, the values in BaseDir and PathDelim are prepended to the relative path information in FileName.

CreateAbsolutePath calls TrimFileName to remove leading or trailing whitespace or duplicate path delimiters in the return value.

Example:

Returns True if it is possible to create a relative path from Source to Dest Function must be thread safe, so no expanding of filenames is done, since this is not thread-safe (at least on Windows platform).

• Dest and Source must either be both absolute filenames, or relative
• Dest and Source cannot contain '..' since no expanding is done by design
• Dest and Source must be on same drive or UNC path (Windows)
• If both Dest and Source are relative they must at least share their base directory
• Double PathDelims are ignored (unless they are part of the UNC convention)
• If UsePointDirectory is True and Result is True then if RelPath is Empty string, RelPath becomes '.'
• If AlwaysRequireSharedBaseFolder is False then Absolute filenames need not share a basefolder
• if the function succeeds RelPath contains the relative path from Source to Dest, no PathDelimiter is appended to the end of RelPath

Examples:

CreateRelativePath is a String function used to get the relative path from BaseDirectory to Filename. A trailing path delimiter in BaseDirectory is ignored. If there is no relative path, the value in Filename is returned.

When BaseDirectory and Filename contain the same value, and UsePointDirectory is False, an empty string ('') is used as the return value. If UsePointDirectory contains True, the return value is the '.' character. Duplicate path delimiters are removed.

FileIsInPath is a Boolean function which indicates if the file name exists in the specified path. Filename is the file name to locate, and may include optional relative path information. For example: '../filename.txt'.

Path is the directory name used to locate the specified file. For example: '/usr/lib/fpc'.

The returns value is True when Filename is a file or directory somewhere below Path. For example, under UNIX the file name '/usr/lib/fpc' is below Path '/usr/lib', '/usr' and '/'. When Filename and Path contain the same value, the return value is False. Please note: the return value is False when Path contains an empty string ('').

FileIsInPath calls ResolveDots to resolve relative path information in both Filename and Path, and ensures that a trailing path delimiter is included in Path when needed. FileIsInPath calls CompareFileNames.

PathIsInPath is a Boolean function used to determine if the specified Directory exists in the Path argument. The return value is False when Path contains an empty string (''), or when the Directory does not exist in Path.

PathIsInPath calls the CompareFilenames routine to determine the return value for the function.

ShortDisplayFilename is a String function used to get a shortened version of the specified file name up to the specified maximum length. The characters '...' are appended to a shortened file name.

The return value is the same as the aFileName argument if the file name did not need to be shortened.

TPathDelimSwitch is an enumerated type with values that indicate how path delimiters in file names are handled in routines like SwitchPathDelims, CheckPathDelim, and IsCurrentPathDelim. Values in the enumeration represent the various platform- or OS-specific path delimiters available in the Lazarus LCL.

PathDelimSwitchToDelim is an array constant with character values for path delimiters associated with TPathDelimSwitch enumeration values. The DirectorySeparator value is used for both pdsNone and pdsSystem enumeration values. For UNIX-like environments (pdsUnix), the Forward slash character ('/' ) is used for the path delimiter. For Windows platforms (pdsWindows) the backslash character ('\') is used for the path delimiter.

ForcePathDelims is a procedure used to ensure that path delimiters in the specified file name are correct for the current platform or OS. ForcePathDelims examines each character in FileName to ensure that path delimiters use the correct notation for the platform or OS defined in the LCL.

For Windows, this means any UNIX path delimiters (/) in FileName are converted into the Windows path delimiter (\). Conversely, for all other platforms and environments, the Windows path delimiter (\) is converted to the UNIX notation (/). All path delimiter substitutions in FileName occur inline.

GetForcedPathDelims is a String function used to perform path delimiter substitutions on the specified file name for the current platform or OS. GetForcedPathDelims calls ForcePathDelims using a copy of FileName as an argument. This ensures that the original file name remains unchanged when path delimiter substitutions are needed.

AppendPathDelim is a String function used to ensure that a trailing path delimiter is included in the specified Path. The return value includes the value in Path and the trailing path delimiter (when needed).

ChompPathDelim is a String function used to remove a trailing path delimiter from the specified value in Path. For environments where UNC paths are allowed, ChompPathDelim ensures that the UNC path delimiters are retained. Windows Device identifiers, such as "D:" are also retained in Path.

SwitchPathDelims is an overloaded String function used to ensure that path delimiter characters in Filename use the required character.

One variant of the function uses the Switch argument to pass a TPathDelimSwitch enumeration value that identifies the path delimiter needed, and includes the following:

pdsNone

No path delimiter substitutions are performed. The original value in Filename is used as the return value for the function.

pdsSystem

Path delimiters use the character required for the current platform or environment running the application.

pdsUnix

Path delimiters use the UNIX forward slash (/) character.

pdsWindows

Path delimiters use the Windows backslash (\) character.

The function examines each character in Filename are replaces any path delimiters encountered with the value specified in Switch.

The other variant passes a Boolean value indicating if all occurrences of a path delimiter should use the character required for the platform or environment hosting the application. It calls the SwitchPathDelims function to perform the substitutions.

The return value contains the value from Filename after any path delimiter substitutions have been applied.

CheckPathDelim is a TPathDelimSwitch function used to determine if a specified path delimiter character is not the one used for the platform or environment running the application. The return value contains an TPathDelimSwitch enumeration value that indicates the path delimiter character notation that does not meet the requirements for the host.

CheckPathDelim compares the value in OldPathDelim to the current PathDelim character for the system. When they are different, the return value is set to reflect the delimiter character in use in OldPathDelim. If they are the same, the return value is set to pdsNone indicating that path delimiter substitutions are not needed.

Changed is a Boolean output parameter that indicates if the value in OldPathDelim does not match the current path delimiter in use on the system running the application. Changed contains False when the current path delimiter matches the value in OldPathDelim.

IsCurrentPathDelim is a Boolean function used to determine if the path delimiter notation specified in Switch matches the current path delimiter for the system.

Switch is a TPathDelimSwitch enumeration value that indicates the notation to compare to the current path delimiter on the system running the application. Switch can include the following values:

pdsNone

No comparison is performed since it is not required. Return value is set True.

pdsSystem

No comparison is performed since it will always match the current path delimiter for the system. Return value is set True.

pdsUnix

Return value is set to True when PathDelim contains the UNIX forward slash (/) character.

pdsWindows

Return value is set to True when PathDelim contains the Windows backslash (\) character.

CreateAbsoluteSearchPath concatenates BaseDirectory and SearchPath to form an absolute path to search for files.

The routine adds the appropriate path delimiters to the BaseDirectory string, and adds the search path. Each directory in the search path is examined to ensure that each is also an absolute directory path. The return value contains the fully-formed absolute search path.

If BaseDirectory is empty, the function exits with a return value equal to SearchPath. if SearchPath is empty, the function exits with empty string ('') in the return value.

CreateRelativeSearchPath is a String function used to resolve one or more paths in SearchPath relative to the directory specified in BaseDirectory. A relative search path is one that assumes the path starts at a given working directory, and could result in an error if that directory is not the current directory on the local file system. CreateRelativeSearchPath ensures that a relative search path is resolved relative to a given directory to provide access to resources in the directory path.

SearchPath can contain multiple path values by using the semicolon character (;) to separate the paths.

BaseDirectory specifies the directory used as the anchor (or root) for each resolved search path.

Paths specified in SearchPath are resolved individually, and recombined with other path values in SearchPath. If either SearchPath or BaseDirectory contain an empty string (''), no actions are performed in the function. The return value contains a copy of the contents in SearchPath with relative paths resolved.

MinimizeSearchPath is a String function used to trim the path(s) specified in SearchPath, and to remove empty or duplicate paths in the argument. SearchPath can contain multiple path specifications separated by the semicolon (';') character.

MinimizeSearchPath iterates over the path specifications in SearchPath and calls TrimFilename as needed. ChompPathDelim is called as well to remove trailing path delimiters as needed. Duplicate occurrence of a search path are reduced to a single occurrence.

The return value contains the value in SearchPath after normalization and removal of duplicate and empty search path specifications.

FindPathInSearchPath is an overloaded function used to locate the path specified in APath in a list of search paths.

APath contains the search path to locate in the delimited list of search paths. A trailing path delimiter specified in APath is ignored.

SearchPath contains the delimited list of search paths examined in the function. No actions are performed in the routine when SearchPath has not been assigned (contains Nil) or contains an empty string ('').

The return value is either an Integer or a PChar value depending on the overloaded variant used in an application. An Integer value represents the position in SearchPath where the value in APath is located. A PChar value contains a pointer to the first character in SearchPath where APath is located. The variant which accepts PChar arguments and returns a PChar value has additional length arguments for the path and search path.

Compiler defines determine the mechanism used to perform a comparison of the values in APath and SearchPath; i.e. CaseInsensitiveFilenames and NotLiteralFilenames. CompareFilenames is called to perform the comparison when inline comparison of string values in not supported.

FileExistsUTF8 is a Boolean function which indicates if the specified file name exists on the local file system. FileExistsUTF8 calls the FileExists function in SysUtils to get the return value for the routine.

FileAgeUTF8 is a Longint function which returns the last modification time for the file specified in FileName. FileAgeUTF8 should not be used on directories; it returns -1 if FileName represents a directory instead of a file.

For UNIX-like environments, the return value is provided by the FileAge function in the SysUtils unit. For Windows, FindFirstFileW is used to get the TWin32FindDataW data for the specified file. Its ftLastWriteTime value is converted using WinToDosTime to get the return value for the function.

The return value is in FileDate format, and can be transformed to a TDateTime value with the FileDateToDateTime function.

DirectoryExistsUTF8 is Boolean function used to determine if the specified path exists on the local file system. For the Windows environment, FileGetAttrUTF8 is called to see if FILE_ATTRIBUTE_DIRECTORY is included in the file attributes for the specified Directory. For UNIX-like environments, the DirectoryExists function in the SysUtils unit is used to get the return value.

ExpandFileNameUTF8 is a String function which expands the UTF-8-encoded values in FileName and BaseDir to an absolute file name. It changes all directory separator characters to the one appropriate for the system.

If an empty string ('') is passed in Filename, it is expanded to the current directory using GetCurrentDirUTF8. When FileName contains the tilde character (~), it is converted to the path to the home directory for the user using the HOME environment variable. Relative paths in FileName are resolved by calling ResolveDots.

FindFirstUTF8 searches the for file which match the value specified in Path. Normal files, as well as all special files which have the attributes specified in Attr will be returned.

It returns a SearchRec record for further searching in Rslt. Path can contain wildcard characters; ? (matches any single character) and * (matches 0 or more arbitrary characters). In this case FindFirstUTF8 will return the first file which matches the specified criteria.

The return value contains the result from GetLastError; a non-zero value indicates that no files matching the criteria were found.

FindNextUTF8 is a Longint function used to locate another file matching the TSearchRec value in Rslt. Rslt is populated in a prior call to FindFirstUTF8, and updated in FindNextUTF8.

For the Windows environment, FindNextFileW is called to compare the TWIN32FINDDATAW for the matching file. For UNIX-like environments, the FindNext function in SysUtils is used.

The return value contains the result from GetLastError; a non-zero value indicates that an error was encountered.

FindCloseUTF8 is a procedure used to free resources allocated to the search record in F by the FindFirstUTF8 routine. FindCloseUTF8 calls the FindClose function in the SysUtils unit.

FileSetDateUTF8 is a Longint function used to set the last modification time for the file to the specified Age in FileDate format. Use DateTimeToFileDate to convert a TDateTime value to FileDate format.

For the Windows environment, a handle is created for the specified file name, and SetFileTime is called to store the updated file age. For UNIX-like environments, FileSetDate in SysUtils is called to set the file age. InvalidateFileStateCache is also called for the specified file name.

The return value is the value from GetLastError; a non-zero value indicates that an error has occurred.

FileGetAttrUTF8 is a Longint function used to get files attributes for the specified file name. For the Windows environment, GetFileAttributesW in Windows is called to the file attribute value for Filename. For UNIX-like environments, FileGetAttr in SysUtils is called to the the return value.

The return value contains a numeric value that can be OR-ed with the following constants to get a specific file attribute:

faReadOnly

The file is read-only

faHidden

The file is hidden (On UNIX, the file name starts with a dot)

faSysFile

The file is a system file (On UNIX, the file is a character, block or FIFO file).

faVolumeId

Volume Label (For DOS/Windows on a plain FAT - not VFAT or Fat32)

faDirectory

File is a directory

faArchive

File is ready to be archived (Not possible on UNIX)

FileSetAttrUTF8 is a Longint function used to set the file attributes for the specified file name to the value in Attr. The value in Attr can be set by AND-ing predefined file attribute constants, such as:

faReadOnly

The file is read-only

faHidden

The file is hidden (On UNIX, the file name starts with a dot)

faSysFile

The file is a system file (On UNIX, the file is a character, block or FIFO file).

faVolumeId

Volume Label (For DOS/Windows on a plain FAT - not VFAT or Fat32)

faDirectory

File is a directory

faArchive

File is ready to be archived (Not possible on UNIX)

For UNIX-like environments, FileSetAttr in SysUtils is called to set the file attributes value. InvalidateFileStateCache is also called for the specified file name. For the Windows environment, SetFileAttributesW in Windows is called to set the attributes value for the specified file name.

The return value contains the result from GetLastError; a non-zero value indicates that an error has occurred.

DeleteFileUTF8 is a Boolean function used to delete the specified file name.

For the Windows environment, DeleteFileW in Windows is called to remove the specified file name. For UNIX-like environments, DeleteFile in the SysUtils unit is called to delete the specified file name. InvalidateFileStateCache is also called.

The return value contains True when Filename is successfully deleted from the local file system.

RenameFileUTF8 is a Boolean function used to rename a file to the value specified in NewName.

For the Windows environment, MoveFileW is called to rename the file using the values specified in OldName and NewName. For UNIX-like environments, RenameFile in SysUtils is called to rename the file to the specified new value. InvalidateFileStateCache is also called.

The return value is True if the file is renamed successfully.

FileSearchUTF8 is a String function used to search for files with the specified name in the list of directory paths.

DirList is a list of file paths to search in the function. Values in DirList are separated by the PathSeparator character for the environment. No additional directories are searched when DirList contains an empty string ('').

ImplicitCurrentDir controls whether the search is implicitly limited to the current directory. The default value for ImplicitCurrentDir is True. When a file with the specified Name is located in the current directory, no additional searches are needed. The return value is the name of the file without any path information.

When ImplicitCurrentDir is False, each path in DirList is searched for a file with the specified name. The search is stopped when the first file with the specified file name is found. The return value contains the path in DirList where the file name was located along with the file name, or an empty string ('') if the specified file is not found in the search.

FileIsReadOnlyUTF8 is a Boolean function used to determine if the specified file is marked as read-only in the local file system. FileIsReadOnlyUTF8 calls FileGetAttrUTF8 for the specified file name and checks to see if faReadOnly has been included in the file attributes value. The return value is True when faReadOnly has been included in the file attributes.

GetCurrentDirUTF8 is a String function used to get the name for the current directory in the local file system.

For the Windows environment, GetCurrentDirectoryW is called to get the current directory name. UTF8Encode is called to convert the WideString value to UTF-8, and used as the return value for the function.

For UNIX-like environments, GetCurrentDir in SysUtils is called to get the current directory name.

SetCurrentDirUTF8 is a Boolean function used to set the current directory in the local file system to the specified value.

For the Windows environment, UTFDecode is called to convert NewDir and passed to SetCurrentDirectoryW to set the current directory name. Windows CE raises an exception in SetCurrentDirUtf8; the concept of a current directory does not exist in Windows CE.

For UNIX-like environments, SetCurrentDir in SysUtils is used to set the current directory to the specified value.

The return value is True if the current directory is successfully changed to the new value.

CreateDirUTF8 is a Boolean function used to create a new directory in the local file system with the specified name. For the Windows environments, the value in NewDir is converted to wide string format and passed to the CreateDirectoryW function in the Windows unit. For UNIX-like environments, CreateDir in SysUtils is used to create the new directory with the specified name.

The return value is True if the new directory is successfully created.

RemoveDirUTF8 is a Boolean function used to remove the directory with the specified name from the local file system.

For the Windows environment, UTF8Decode is called to convert the value in Dir to wide string format. The RemoveDirectoryW function in the Windows unit is called to remove the specified directory.

For UNIX-like environments, RemoveDir in SysUtils is called to remove the specified directory.

The return value is True when the specified directory is successfully removed.

ForceDirectories is a Boolean function which creates the specified directories if they do not already exist. ForceDirectories examines the value in Dir to determine if it contains a Windows device identifier or a UNC name. If a device identifier or UNC name is found, but not supported on the platform, no actions are performed in the function.

ForceDirectories raises an EInOutError exception with the message in SCannotCreateEmptyDir when Dir contains an empty string ('').

Each directory in the specified path is checked using DirectoryExistsUTF8. ForceDirectories calls CreateDirUTF8 if a directory does not already exist, and may exit with a return value of False if directory creation is not successful. The return value is True if all directories in the path information already exist, or are successfully created in the function.

FileOpenUTF8 is a THandle function used to open the UTF-8-encoded file name in FileName, and return its file handle. FileOpenUTF8 converts the file name to system format by calling UTF8ToSys, and calls the FileOpen routine in the SysUtils unit to get the file handle for the opened file.

FileCreateUTF8 is a THandle function used to created the file specified in the UTF-8-encoded FileName argument, and returns the file handle for the newly created file. Overloaded variants of the function are provided which allow additional arguments that specify the file sharing mode, or access rights for the newly created file.

FileCreateUTF8 calls UTF8ToSys to convert the file name to its system representation, and calls the FileCreate routine in the SysUtils unit to create the file and get its file handle.

FileSizeUTF8 is an Int64 function used to get the size for the file specified in the UTF-8-encoded Filename argument. FileSizeUTF8 calls Utf8ToSys to convert the value in Filename to the system string type type, and calls the FindFirst routine in the SysUtils unit to get the size for the specified file name.

GetFileDescription is a String function used to get descriptive information for the file name specified in AFilename. The return value contains file information appropriate to the platform, environment, or file system. The implementation of GetFileDescription and the content of the return value are platform- or OS-specific.

For UNIX-like environments, the return value can contain information that indicates the permissions for the user, group, and owner of the file as returned from the FPStat routine. It also includes the file user and group IDs, file size, and modification timestamp. For example:

l

File is a symbolic link

d

File is a directory in the file system

b,c, or -

Device type for the entry. b is for block-level devices. c is for character devices. All others device types contain the - character.

r or -

User read access permission

w or -

User write access permission

x or -

User executable permission

r or -

Group read access permission

w or -

Group write access permission

x or -

Group executable permission

r or -

Other read access permission

w or -

Other write access permission

x or -

Other executable permission

UID

User identifier number assigned as the owner of the file

GID

Group identifier number assigned to the group which owns the file

99999

Size of the file. May indicate the total number of blocks or characters depending on the device type for the file.

MM/DD/YYYY hh:nn or ?

Creation/modification timestamp for the file. ? is included if an exception is raised when accessing the date/time value.

For the Amiga platform, the content in the return value is derived using a TFileInfoBlock for a shared lock on the file. The return value can be an empty string if the file could not be locked using a shared lock on the file system. It can contain values like the following:

a

File is an archived (unchanged) file

s

File is a script or executable file

p

File is command or program that can be made resident

e

File is used by the Shell

r

File is readable

w

File is writable

d

File cannot be deleted

For Windows platforms, the return value contains only the modification date / time for the file using the format:

The return value can be 'Modified: ?' if an exception is encountered when getting the date/time value for the file.

ReadAllLinks is a String function used to resolve a symbolic link to an actual file name. It does not resolve symbolic links in parent (or ancestor) directories.

If a symlink cannot be resolved, and ExceptionOnError is False, the function returns an empty string (''). If ExceptionOnError is True, it raises an EFOpenError with a message containing more details. For the Windows platform, it simply returns the value in the Filename argument.

If a symlink can not be resolved it returns Filename. It calls the ReadAllLinks function in its implementation.

GetShellLinkTarget is a String function used to resolve the Shell Link file in the FileName parameter to a path on the local system. The return value contains the qualified path to the Shell object in the Link file.

Shell links are a feature available in Windows desktop and server operating systems. It relies on the Shell Object namespace, and provides access to files, folders, disk drives and printers on the system. The Shell Link allows access to an object from anywhere in the Shell namespace, and does not need to know the current name and / or location for the object.

GetShellLinkTarget is implemented for UNIX-like platforms and Amiga, but simply returns the value in the FileName parameter.

The Windows CE platform does not have the IShellLinkW interface; the value in FileName is always used as the return value.

FileName must contain a file name that uses the .lnk file extension, as created using the Create Shortcut option in Windows Explorer. No actions are performed in the routine when FileName does not use the .lnk file extension; the return value contains the original value passed in the FileName parameter.

GetShellLinkTarget uses the IShellLinkW interface to resolve the Shell Link to the path for the Shell object.

Attr contains the file attributes examined in the routine, with the following values displayed for the corresponding file attributes:

-1

Invalid

faDirectory

D

faArchive

A

faSysFile

S

faReadOnly

R

faHidden

H

faVolumeId

V

faSymLink

L

File attributes not found in Attrib are represented as '-' characters.

TPhysicalFilenameOnError is an enumerated type with values that indicate the action taken when an error is encountered when retrieving the physical file name for a symbolic link on the local file system.

TPhysicalFilenameOnError is the type used to represent the OnError argument passed to the GetPhysicalFilename function.

GetPhysicalFilename is a String function used to get the physical file name on the local file system for the specified symbolic link.

Filename contains the symbolic link to resolve in the function.

OnError is a TPhysicalFilenameOnError enumeration value that indicates the action performed if a physical file name cannot be determined for the symbolic link. When OnError contains pfeException, an exception is raised for the unresolved file name. When OnError contains pfeOriginal, the unresolved symlink is used as the return value.

The implementation of GetPhysicalFilename is platform- or OS-dependent. For UNIX-like environments (which support symbolic links), the GetUnixPhysicalFilename function is called to retrieve the file name for the symlink. For other platforms and environments, like Amiga and Windows, symbolic links are not supported and the return values always contains the value in Filename.

If a symlink can not be resolved, and ExceptionOnError is False, the function returns an empty string (''). If ExceptionOnError is True, it raises an EFOpenError exception with a message containing more details.

GetUnixPhysicalFilename is used to implement the GetPhysicalFilename function for UNIX-like environments.

GetAppConfigDirUTF8 is a String function used to get the directory on the local file system where application configuration and data files are stored.

Global is a Boolean argument that determines if the directory is user- or system- specific. When Global contains False, the home directory for the user is used as the path in the return value.

Create is a Boolean argument that indicates if the configuration directory should be created if not already present on the local file system.

The implementation of GetAppConfigDirUTF8 is platform- and/or OS-specific.

For the Amiga platform, the GetAppConfigDir in the SysUtils unit is called to get the return value.

For Windows environments, the SHGetFolderPathUTF8 function is called to get the path information. The CSIDL (Constant Special Item ID List) required for the setting in Global and the target platform is passed to the routine. When VendorName is provided, it is appended to the path information. ApplicationName is also appended to the path information. If the path cannot be determined, the value from DGetAppConfigDir is used as the directory path.

For UNIX-like environments, the GetAppConfigDir function in the SysUtils unit is called to get the path information.

If the directory does not exist and Create contains True, the ForceDirectoriesUTF8 routine is called to create any missing directories for the path. An EInOutError exception is raised if any missing directory in the path cannot be created.

GetAppConfigDirUTF8 is used in the implementation of the Lazarus IDE and help viewer (LHelp).

GetAppConfigFileUTF8 is a String function used to get a UTF-8-encoded configuration file name for the current application. GetAppConfigFileUTF8 calls the GetAppConfigFile function in the SysUtils unit to get the return value for the function. SysToUTF8 is called for the file name to ensure that it is encoded using the UTF-8 encoding scheme.

Global is a Boolean which indicates whether system- or user-specific path information is used in the configuration file name. When Global contains True, the system-wide configuration path is used in the return value. Otherwise, a user-specific path is used in the return value.

SubDir is a Boolean value that indicates if a sub-directory for the application is included in the path for the configuration file. When SubDir is True, a "Config" sub-directory is included in the path information.

CreateDir is a Boolean argument that indicates if any missing directories in the configuration file path are created in the function. When CreateDir is False, no additional actions are performed in the function. Otherwise, the path information is passed to ForceDirectoriesUTF8 to create any missing directories. If any of the directories are not successfully created, an EInOutError exception is raised with the message in lrsUnableToCreateConfigDirectoryS.

The return value contains the path to the configuration file including the requested path, configuration file name, and configuration file extension.

GetTempFileNameUTF8 is a String function used to get a temporary file name with the specified prefix located in the specified directory.

Dir contains the path on the local file system where the temporary file should be located.

Prefix contains the prefix for the temporary file name. In other words, the temporary file name must start with this sequence of characters.

GetTempFileNameUTF8 signals the OnGetTempFile event handler (when assigned) to get the value used as the temporary file name. When OnGetTempFile has not been assigned, a string is constructed using the path information in Dir and a numeric suffix to make the file name unique. For example:

GetTempFileNameUTF8 examines the files in the specified directory to determine if a file already exists which starts with the value in Prefix. If a file is located in the directory, a numeric suffix (starting at 0) is appended to the base file name in Prefix to build a temporary file name which does not already exist in the directory.

IsUNCPath is a Boolean function which indicates is the specified path uses Universal Naming Convention (UNC).

The implementation of IsUNCPath is platform- and/or OS-specific. For the Windows platform, IsUNCPath checks Path to see if it begins with the double backslash notation used for a UNC path. For example:

For UNIX-like environments, as well as the Amiga platform, the return value is always False. UNC paths are not used on those platforms.

Use ExtractUNCVolume to get host and path information from a file name expressed using UNC notation.

ExtractUNCVolume is a String function used to get host and volume information from a path specified using Universal Naming Convention (UNC). UNC notation is recognized using both the long and short formats defined for the naming convention.

The return value contains information needed to access shared resources by their host and volume names, and contains one of the following formats:

ExtractUNCVolume calls the IsUNCPath function to determine if the value in Path starts with the UNC naming delimiters. The return value is an empty string (''), and no additional actions are performed in the function, when Path does not use UNC notation.

ExtractUNCVolume examines the characters in Path to determine if it uses the long or the short format for UNC notation. Long format notation begins with the characters '\\?\' or '\\?\UNC\' followed by a drive designation and optional path information such as 'c:\'. Short format notation uses a host name and a shared resource identifier such as '\\mypc\nas-drive\'.

ExtractFileRoot is a String function used to get the root directory for the specified file name. It is file system-aware and includes the drive and/or volume information needed for the file name specified in the FileName argument.

When FileName uses Universal Naming Convention (UNC), the return value will contain any server and share/volume information included in the parameter. For example:

For UNIX-like environments (as well as WinCE), an initial path delimiter marks the root directory in the file system.

For the Amiga platform, any characters in FileName up to (but not including) the first ":" character are used as the root directory.

For the Windows platform, a drive designation up to and including the first path delimiter are used as the root directory. For example:

Parameters are separated by one or more whitespace characters (#9,#10,#13,#32). Quoted values are parsed as a single parameter. If ReadBackslash contains True, then \" is replaced with " and not treated as a quoted value. #0 is always treated as the end of the Parameters value.

The following actions are performed for values in the Param argument:

• An empty string is converted to ''.
• Values separated by space characters are enclosed by Quote (') characters.
• An existing Quote (') character causes the value to be enclosed by Double Quote (") characters.
• An existing Double Quote character causes a value to be enclosed by Quote characters.
• A null byte (#0) causes the remainder of the Param value to be discarded.

MergeCmdLineParams is a String function used to convert parameter values in the ParamList argument to a normalized string using the quoting needed for the parameter values.

MergeCmdLineParams iterates over the string values in ParamList, and calls StrToCmdLineParam to normalize the whitespace and quoting in each value. The sanitized parameters values are concatenated together, using the Space (' ') as the delimiter between the parameter values, and used as the return value for the function.

No actions are performed in the routine when ParamList is unassigned (Nil) or its Count property is 0 (zero).

SplitCmdLine is a routine used to separate values found in the CmdLine argument into the ProgamFilename and Params arguments. Outer single and double quote characters found in the CmdLine argument are removed in the method.

No actions are performed in the routine when CmdLine is an empty string (''); the output parameters are set to empty string values as well.

TInvalidateFileStateCacheEvent is the type which specifies the event signalled for an invalid file state in the file cache. TInvalidateFileStateCacheEvent is the type used for the OnInvalidateFileStateCache event handler signalled in the InvalidateFileStateCache procedure.

OnInvalidateFileStateCache is a TInvalidateFileStateCacheEvent variable which implements the event handler signalled for a file with an invalid file state. OnInvalidateFileStateCache allows an application to respond to the event notification for a specific file. OnInvalidateFileStateCache is signalled when InvalidateFileStateCache is called by routines that perform file manipulation.

OnInvalidateFileStateCache is significant for UNIX-like environments only, such as Linux and Amiga. OnInvalidateFileStateCache is not used in Windows environments.

InvalidateFileStateCache is a procedure used to signal the OnInvalidateFileStateCache event handler for the specified file name. InvalidateFileStateCache is used when an invalid file state is detected in routines which perform file manipulation, such as:

• DeleteFileUTF8
• FileSetAttrUTF8
• FileSetDateUTF8
• RenameFileUTF8

InvalidateFileStateCache is significant for UNIX-like environments only, such as Linux and Amiga. InvalidateFileStateCache is not used for the Windows platform.