Using Memory Variable Files (.MEM) in FoxPro (97637)

SUMMARY

Memory variable files are a way to store the status of memory variables that are currently stored in memory and use them later in the same program or in another session of FoxPro.

The commands used when creating and using .MEM files are as follows:

   SAVE TO <file>|TO MEMO <memo field> [ALL LIKE|ALL EXCEPT <skel>]

and

   RESTORE FROM <file>|FROM MEMO <memo field> [ADDITIVE]

MORE INFORMATION

A few things that are important to remember when using memory variable files:

All memory variables that are stored in the .MEM file, regardless of being declared PUBLIC or PRIVATE, are treated as PRIVATE variables if they are restored in a program unless the ADDITIVE clause is added to the RESTORE FROM command. They are treated as PUBLIC variables if they are restored from the Command window.

Following is an example of using the RESTORE FROM....ADDITIVE clause to declare a restored memory variable as PUBLIC in a program:
```
      PROG1.PRG

      val1 = 12
      val2 = "test"
      SAVE TO temp

      PROG2.PRG

      PUBLIC val2
      RESTORE FROM temp
      DISPLAY MEMORY LIKE val?
      CLEAR ALL
      PUBLIC val2
      RESTORE FROM temp ADDITIVE
      DISPLAY MEMORY LIKE val?
						
```
All variables currently in memory will be placed in the .MEM file unless the ALL EXCEPT or ALL LIKE options are included with the SAVE TO command. The wildcard characters ? and * can be used with these options.

To exclude variables, use the ALL EXCEPT <skel> option of the SAVE TO command. For example:
```
      SAVE TO test ALL EXCEPT v*
						
```
To include variables, use the ALL LIKE <skel> option of the SAVE TO command. For example:
```
      SAVE TO test ALL LIKE var?
						
```
System memory variables are not affected by RESTORE FROM or SAVE TO commands.
Any memory variables or arrays currently in memory are erased unless the ADDITIVE clause is included with the RESTORE FROM command. If a variable brought in has the same name as an existing variable, the value of the variable in the memory file will replace the current value.
If the number of variables that will be brought in by the RESTORE FROM ADDITIVE command exceeds the MVCOUNT limit when added to the variables currently in memory, the maximum number possible will be restored. The MVCOUNT setting is stored in the CONFIG.FP file with the default setting of 256 variables.