Geoff Chappell - Software Analyst
The !vc7fpo command toggles an option for stack walking.
This command has no arguments.
The !vc7fpo command and equivalent vc7fpo function are implemented in DBGHELP.DLL. They affect all that module’s stack-walking services, most notably the StackWalk64 function, including its use for the k command in debuggers (such as WinDbg) that are DBGENG clients.
The command toggles whether the “VC7 FPO” feature for stack walking is enabled or disabled, and then displays what is now the current setting. The initial setting is that “VC7 FPO” is enabled.
The vc7fpo function is exported from DBGHELP.DLL as a 64-bit WinDbg extension command, making it accessible as the command !vc7fpo in any sufficiently recent DBGENG client. In terms of DBGHELP versions distributed with Windows, as opposed to the separate package of Debugging Tools for Windows, it dates from Windows XP.
The !vc7fpo command is superseded by !stackdbg in Windows Vista, not that either is yet documented.