Retrieving Symbol Information by Name

The following code demonstrates how to call the SymGetSymFromName function. This function fills in an IMAGEHLP_SYMBOL structure. Because the name is variable in length, you must supply a buffer that is large enough to hold the name stored at the end of the IMAGEHLP_SYMBOL structure. Also, the MaxNameLength member must be set to the number of bytes reserved for the name. In this example, szSymbolName is a buffer that stores the name of the requested symbol.

BYTE szSymbolName[256];
BYTE buffer[256];
PIMAGEHLP_SYMBOL pSymbol = (PIMAGEHLP_SYMBOL)buffer;

lstrcpy(szSymbolName, "WinMain");
pSymbol->SizeOfStruct = sizeof(IMAGEHLP_SYMBOL);
pSymbol->MaxNameLength = sizeof(buffer) - sizeof(IMAGEHLP_SYMBOL) + 1;

if (SymGetSymFromName(hProcess, szSymbolName, pSymbol))
{
    // SymGetSymFromName returned success
}
else
{
    // SymGetSymFromName failed
    error = GetLastError();
    printf("SymGetSymFromName returned error : %d\n", error);
}

If an application has a module or source file name as well as line number information, it can use SymGetLineFromName to retrieve a virtual code address. This function requires a pointer to an IMAGEHLP_LINE structure to receive the virtual code address. Note that the symbol handler can retrieve line number information only when SYMOPT_LOAD_LINES option is set using the SymSetOptions function. This option must be set before loading the module. The szModuleName parameter contains the source module name; it is optional and can be NULL. The szFileName parameter should contain the source file name, and dwLineNumber parameter should contain the line number for which the virtual address will be retrieved.

BYTE      szModuleName[MAX_PATH];
BYTE      szFileName[MAX_PATH];
DWORD dwLineNumber;
LONG     lDisplacement;
IMAGEHLP_LINE line;

SymSetOptions(SYMOPT_LOAD_LINES);

line.SizeOfStruct = sizeof(IMAGEHLP_LINE);
lstrcpy(szModuleName, "MyApp");
lstrcpy(szFileName, "main.c");
dwLineNumber = 248;

if (SymGetLineFromName(hProcess, szModuleName, szFileName,
    dwLineNumber, &lDisplacement, &line))
{
    // SymGetLineFromName returned success
}
else
{
    // SymGetLineFromName failed
    error = GetLastError();
    printf("SymGetLineFromName returned error : %d\n", error);
}