Change the values of variables

You can change the values of variables while in debug mode.

To change the value of a program variable, use the Change Program Variable (CHGPGMVAR), the Change HLL Pointer (CHGHLLPTR), or the Change Pointer (CHGPTR) command. Changing the value of a program variable consists of specifying the variable name and a value that is compatible with the data type of the variable. For example, if the variable is character type, you must enter a character value.

When changing the value of variables, you should be aware of whether the variable is an automatic variable or a static variable. The difference between the two is in the storage for the variables. For automatic variables, the storage is associated with the call of the program. Every time a program is called, a new copy of the variable is placed in automatic storage. A change to an automatic variable remains in effect only for the program call the change was made in.

Note: In some languages, the definition of a call is made at the procedure level and not just at the program level. For these languages, storage for automatic variables is associated with the call of the procedure. Every time a procedure is called, a new copy of the variable is gotten. A change to an automatic variable remains in effect only while that procedure is called. Only the automatic variables in the most recent procedure call can be changed. The RCRLVL (recursion level) parameter on the commands applies only on a program basis and not on a procedure basis.

For static variables, the storage is associated with the activation. Only one copy of a static variable exists in storage no matter how many times a program is called. A change to a static variable remains in effect for the duration of the activation.

To determine if a program variable is a static or an automatic variable, request an intermediate representation of a program (IRP) list (*LIST and *XREF on the GENOPT parameter) when the program containing the variables is created.

When changing a variable that is an array, you must specify one element of the array. Consequently, you must specify the subscript values for the array element you want to change.