casa::AppInfo Class Reference [System_module]

General information for applications. More...

#include <AppInfo.h>

List of all members.

Static Public Member Functions
static Vector< String >	workDirectories (uInt minimumFreeSpaceInMB=0)
	Return a list of directory names into which the user may write data.
static String	workDirectory (uInt minimumFreeSpaceInMB=0)
	Choose a workDirectory with at least minimumFreeSpace MB of free space available.
static String	workFileName (uInt minimumFreeSpaceInMB=0, const String &filenamePrefix="aipstmp_")
	This function returns a fully qualified filename for a non-existent file in a work directory with enough free space.
static Double	timeZone ()
	Return the local time zone offset in day fractions.
Static Private Member Functions
static void	init ()
	Force an initialization of the AppInfo values.
Static Private Attributes
static Bool	need_init_p
static uInt	tz_r

---

Detailed Description

General information for applications.

Intended use:

Public interface

Review Status

Reviewed By:

wbrouw

Date Reviewed:

1997/10/30

Test programs:

tAppInfo

Prerequisite

• Aipsrc class

Synopsis

This class provides general information that an application might want to know about its processing environment. This will be based either on information coded into aipsrc variables, or on information which can be obtained directly from some other source. For example, the time zone will generally be obtained from the host OS, but it can be overridden by an aipsrc variable if necessary.

Generally speaking, this class is provided to hide the details of how the information is encoded into an aipsrc variables and to avoid having to change applications if the information moves from being coded into a variable to being deduced at runtime.

It is expected that the information which is available from this class will accrete with time.

Motivation

Further encapsulate information which is usually in aipsrc variables.

Thrown Exceptions

• AipsError if abs(timeZone()) > 0.625

Definition at line 84 of file AppInfo.h.

---

Member Function Documentation

static void casa::AppInfo::init

(

)

[static, private]

Force an initialization of the AppInfo values.

Referenced by timeZone().

Double casa::AppInfo::timeZone

(

)

[inline, static]

Return the local time zone offset in day fractions.

This value has to be added to UTC to get local time. Generally the OS supplied value will be used, however it can be overridden with system.time.tzoffset if necessary.

Definition at line 143 of file AppInfo.h.

References init(), need_init_p, and tz_r.

static Vector<String> casa::AppInfo::workDirectories

(

uInt

minimumFreeSpaceInMB = 0

)

[static]

Return a list of directory names into which the user may write data.

If minimumFreeSpace is set (>0) then only directories with at least that much free space (in megabytes) are returned. If the aipsrc variable user.directories.work is set, the candidate directories are taken from that variable, otherwise the current working directory (".") is chosen if it exists and is writeable, otherwise /tmp is the candidate. Only one of "." and "/tmp" is chosen, not both.

If no suitable directories are found (i.e., writable directories with enough free space), a zero-length vector is returned. A warning is issued to the logging system for directories which do not exist or are not writable.

static String casa::AppInfo::workDirectory

(

uInt

minimumFreeSpaceInMB = 0

)

[static]

Choose a workDirectory with at least minimumFreeSpace MB of free space available.

It uses workDirectories. If there is more than one valid directory it arranges to choose different directories in succession in an attempt to spread out the I/O. That is, on the first call it will return directory1, on the second it will return directory2, etc. in a cyclical fashion. One can imagine more elaborate algorithms than this, however this should suffice for some time, if not forever.

Thrown Exceptions

• An AipsError is thrown if no directory with enough free space is found.

static String casa::AppInfo::workFileName	(	uInt	minimumFreeSpaceInMB = 0,
		const String &	filenamePrefix = "aipstmp_"
	)			[static]

This function returns a fully qualified filename for a non-existent file in a work directory with enough free space.

That is, you can create a temporary file with the name returned from this function. This function calls workDirectory and then appends a unique (file does not exist) filename. By default the prefix of temporary file name is aipstmp_, but you can override this if you choose.

Thrown Exceptions

• An AipsError is thrown if no directory with enough free space is found.

---

Member Data Documentation

Bool casa::AppInfo::need_init_p [static, private]

Definition at line 134 of file AppInfo.h.

Referenced by timeZone().

uInt casa::AppInfo::tz_r [static, private]

Definition at line 135 of file AppInfo.h.

Referenced by timeZone().

---

The documentation for this class was generated from the following file:

• casa/System/AppInfo.h