Here are some tips of Microsoft Visual Studio 6.0.

Display the LastError’s value

When we want to get the LastError message, we often using the following code.

LPVOID lpMsgBuf;
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
GetLastError(),
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
(LPTSTR) &lpMsgBuf,
0,
NULL
);
// Process any inserts in lpMsgBuf.
// …
// Display the string.
MessageBox( NULL, (LPCTSTR)lpMsgBuf, “Error”, MB_OK | MB_ICONINFORMATION );
// Free the buffer.
LocalFree( lpMsgBuf );


But now VisualSudio 6.0 has provied a virtual Pseudoregister called @ERR
we can simply input the expression in the watch window and we will get the LastError message.@ERR,hrHere is supported pseudoregisters list:[1]


@ERR
;Last error value,the same value returned by the GetLastError() API function

@TIB
;Thread information block for the current thread

@CLK
;Undocumented clock register; usable only in the Watch window

@EAX, @EBX, @ECX, @EDX, @ESI, @EDI, @EIP, @ESP, @EBP, @EFL
;Intel CPU registers

@CS, @DS, @ES, @SS, @FS, @GS
;Intel CPU segment registers

@ST0, @ST1, @ST2, @ST3, @ST4, @ST5, @ST6, @ST7
;Intel CPU floating-point registers

Acknowledge:

[1]An introduction to debugging in MSVC++ using Pseudoregisters

[2]Microsoft Visual C++ Tips and Tricks

Tags: Debug, Visual Studio