Variable Access

The Variable Access pane displays global variables (and local static variables). For each global variable, the pane lists all functions and tasks performing read/write access on the variables, along with their attributes, such as values, read/write accesses and shared usage.

For each variable and each read/write access, the Variable Access pane contains the relevant attributes. For the variables, the various attributes are listed in this table.

AttributeDescription
Variables

Name of Variable

FileSource file containing variable declaration
Values

Value (or range of values) of variable

This column is empty for pointer variables.

# ReadsNumber of times the variable is read
# WritesNumber of times the variable is written
Written by taskName of tasks writing on variable
Read by taskName of tasks reading variable
Protection

Whether shared variable is protected from concurrent access

(Filled only when Usage column has entry, Shared)

The possible entries in this column are:

  • Critical Section: If variable is accessed in critical section of code

  • Temporal Exclusion: If variable is accessed in mutually exclusive tasks

For more details on these entries, see Multitasking.

UsageShared, if variable is shared between tasks; otherwise, blank
LineLine number of variable declaration
ColColumn number (number of characters from beginning of line) of variable declaration
Data TypeData type of variable (C/C++ data types or structures/classes)

Double-click a variable name to view read/write access operations on the variable. The arrowhead symbols and in the Variable Access pane indicate functions performing read and write access respectively on the global variable. Likewise, tasks performing read and write access are indicated by the symbols and respectively. For further information on tasks, see Tasks (-entry-points).

For access operations on the variables, the various attributes described in the pane are listed in this table.

AttributeDescription
Variables

Names of function (or task) performing read/write access on the variable

Values

Value or range of values of variable in the function or task performing read/write access

This column is empty for pointer variables.

Written by taskOnly for tasks: Name of task performing write access on variable
Read by taskOnly for tasks: Name of task performing read access on variable
LineLine number where function or task accesses variable
ColColumn number where function or task accesses variable
FileSource file containing access operation on variable

For example, consider the global variable, SHR2:

The function, Tserver, in the file, tasks1.c, performs two write operations on SHR2. This is indicated in the Variable Access pane by the two instances of Tserver() under the variable, SHR2, marked by . Likewise, the two write accesses by tasks, server1 and server2, are also listed under SHR2 and marked by .

The color scheme for variables in the Variable Access pane is:

  • Black: global variable.

  • Orange: global variable, shared between tasks with no protection against concurrent access.

  • Green: global variable, shared between tasks and protected against concurrent access.

  • Gray: global variable, declared but not used in reachable code.

If a task performs certain operations on a global variable, but the operations are in unreachable code, the tasks are colored gray.

The information about global variables and read/write access operations obtained from the Variable Access pane is called the data dictionary.

You can also perform the following actions from the Variable Access pane.

  •  View Access Graph

  •  View Structured Variables

  •  View Operations on Anonymous Variables

  •  View Access Through Pointers

  •  Show/Hide Callers and Callees

  •  Hide Access in Unreachable Code

  •  Limitations