BUG: CHRTRAN(), CHRTRANC(), and FULLPATH() May Cause GPF Errors

• Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a

SYMPTOMS

Visual FoxPro 5.0x produces random General Protection Faults or other memory related errors in the development or run-time environment and in Visual FoxPro OLE Automation Servers. Often, these errors are random and difficult, if not impossible, to reproduce consistently.

CAUSE

In certain circumstances the CHRTRAN(), CHRTRANC(), and FULLPATH() functions are reading past the allocated buffer in memory.

RESOLUTION

Use another string manipulation function to replace CHRTRAN(), CHRTRANC() or FULLPATH(). Check the Help file topic of each of the three functions and press the "See Also" jump for alternate functions that may be helpful.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

These functions do not produce errors each time they are used. Often, a programmer can rely on these functions to work without causing a problem. The success or failure of these functions depends on how memory is allocated in Visual FoxPro at a given time. Therefore, one application may work fine while another produces memory errors. Since Visual FoxPro's internal memory allocation depends on many factors that the programmer does not control, the problem may appear intermittently.

This problem occurs most frequently when Visual FoxPro 5.0x runs on Windows NT 4.0 computers. However, this behavior may also occur on Windows 95 computers. Anytime you experience random memory problems that are difficult to reproduce, remove any occurrences of the FULLPATH(), CHRTRANC(), and CHRTRAN() functions and retest the application.

Currently, we do not have a programmatic scenario that reliably reproduces the behavior. If you develop a code example that duplicates this behavior, please contact Microsoft Product Support Services.

REFERENCES

Visual FoxPro Help; search on: "FULLPATH()";"CHRTRAN()";"CHRTRANC()"