Using External Code in LabVIEW

Chapter 6 Function Descriptions

FCopy

MgErr FCopy(oldPath, newPath);

Purpose

Copies a file, preserving the type, creator, and access rights. The file to be copied must not be open. If an error occurs, the new file is not created.

Parameters

Name	Type	Description
oldPath	Path	Path of the file or directory you want to copy.
newPath	Path	Path, including filename, where you want to
		store the new file.

Return Value

mgErr, which can contain the following errors:

mgArgErr	A bad argument was passed to the function. Verify the path.
fNotFound	File not found.
fNoPerm	Access was denied; the file, directory, or disk is locked or
	protected.
fDiskFull	Disk is full.
fDupPath	The new file already exists.
fIsOpen	The original file is open for writing.
fTMFOpen	Too many files are open.
mFullErr	Insufficient memory.
fIOErr	Unspecified I/O error.

6-54	www.ni.com

Chapter 6 Function Descriptions

FCreate

MgErr FCreate(fdp, path, permissions, openMode, denyMode, group);

Purpose

Creates a file with the name and location specified by path and with the specified permissions, and opens it for writing and reading, as specified by openMode. If the file already exists, the function returns an error.

You can use denyMode to control concurrent access to the file from within LabVIEW. You can use the group parameter to assign the file to a UNIX group; in Windows or Macintosh, group is ignored.

If the function creates the file, the resulting file descriptor is stored in the address referred to by fdp. If an error occurs, the function stores 0 in the address referred to by fdp and returns an error.

Note Before you call this function, make sure that you understand how to use the fdp parameter. Refer to the Pointers as Parameters section in Chapter 3, CINs, for more information about using this parameter.

Parameters

Name	Type	Description
fdp	File *	Address at which FCreate stores the file
		descriptor for the new file. If FCreate fails,
		it stores 0 in the address fdp. Refer to the
		Pointers as Parameters section in Chapter 3,
		CINs, for more information about using this
		parameter.
path	Path	Path of the file you want to create.
permissions	int32	Permissions to assign to the new file.
openMode	int32	Access mode to use in opening the file. The
		following values are defined in the file
		extcode.h:
		• openReadOnly—Open for reading.
		• openWriteOnly—Open for writing.
		• openReadWrite—Open for both
		reading and writing.

© National Instruments Corporation

6-55

Using External Code in LabVIEW

File is already open for writing. This error is returned only in Macintosh and Solaris. Windows returns fIOErr when the file is already open for writing.

Access was denied, because the file is locked or protected. A file of that name already exists.

Too many files are open. Unspecified I/O error.

A bad argument was passed to the function. Verify the path.

Chapter 6 Function Descriptions

Name	Type		Description
denyMode	int32	Mode that determines what level of
		concurrent access to the file is allowed.
		The following values are defined in the file
		extcode.h:
		•	denyReadWrite—Prevents others
			from reading from and writing to
			the file while it is open.
		•	denyWriteOnly—Prevents others
			from writing to the file only while it
			is open.
		• denyNeither—Allows others to
			read from and write to the file while
			it is open.
group	PStr	UNIX group you want to assign to the new
		file.

Return Value

mgErr, which can contain the following errors: mgArgErr

fIsOpen

fNoPerm fDupPath fTMFOpen fIOErr

Using External Code in LabVIEW

6-56

www.ni.com

Chapter 6 Function Descriptions

FCreateAlways

MgErr FCreateAlways(fdp, path, permissions, openMode, denyMode, group);

Purpose

Creates a file with the name and location specified by path and with the specified permissions, and opens the file for writing and reading, as specified by openMode. If the file already exists, this function opens and truncates the file.

You can use denyMode to control concurrent access to the file from within LabVIEW. You can use the group parameter to assign the file to a UNIX group; in Windows or Macintosh, group is ignored.

If the function creates the file, the resulting file descriptor is stored in the address referred to by fdp. If an error occurs, the function stores 0 in the address referred to by fdp and returns an error.

Note Before you call this function, make sure that you understand how to use the fdp parameter. Refer to the Pointers as Parameters section in Chapter 3, CINs, for more information about using this parameter.

Parameters

Name	Type	Description
fdp	File *	Address at which FCreateAlways stores
		the file descriptor for the new file. If
		FCreateAlways fails, it stores 0 in the
		address fdp. Refer to the Pointers as
		Parameters section in Chapter 3, CINs, for
		more information about using this parameter.
path	Path	Path of the file you want to create.
permissions	int32	Permissions to assign to the new file.
openMode	int32	Access mode to use in opening the file.
		The following values are defined in the file
		extcode.h:
		• openReadOnly—Open for reading.
		• openWriteOnly—Open for writing.
		• openReadWrite—Open for both
		reading and writing.

© National Instruments Corporation

6-57

Using External Code in LabVIEW

File is already open for writing. This error is returned only in Macintosh and Solaris. Windows returns fIOErr when the file is already open for writing.

Access was denied, because the file is locked or protected. A file of that name already exists.

Too many files are open. Unspecified I/O error.

A bad argument was passed to the function. Verify the path.

Chapter 6 Function Descriptions

Name	Type		Description
denyMode	int32	Mode that determines what level of
		concurrent access to the file is allowed.
		The following values are defined in the file
		extcode.h:
		•	denyReadWrite—Prevents others
			from reading from and writing to
			the file while it is open.
		•	denyWriteOnly—Prevents others
			from writing to the file only while it
			is open.
		• denyNeither—Allows others to
			read from and write to the file while
			it is open.
group	PStr	UNIX group you want to assign to the new
		file.

Return Value

mgErr, which can contain the following errors: mgArgErr

fIsOpen

fNoPerm fDupPath fTMFOpen fIOErr

Using External Code in LabVIEW

6-58

www.ni.com