pointer to function

[Cmdr0Sunburn]

hi, im reading a boox that explayed pointers to functions. but my compiler gets "error C2064: term does not evaluate to a function"


void Initialize()
{
SYSTEM_TIME_INFORMATION SysTimeInfo ;
SYSTEM_PERFORMANCE_INFORMATION SysPerfInfo ;
int retr;
HINSTANCE__ *retrh;
;

retrh = LoadLibrary("NTDLL.DLL");
GetProcAddress(retrh,"NtQuerySystemInformation");
__asm {

mov NtQuerySystemInformation,eax
}

retr = NtQuerySystemInformation(SYSTEM_TIMEINFORMATION, *SysTimeInfo, sizeof(SysTimeInfo), 0);
return;
}

[CornedBee]

Uh, how did you define NtQuerySystemInformation?

If you define it correctly you can just do
NtQuerySystemInformation = GetProcAddress(...)

The first parameter to GetProcAddress should be a HMODULE, not int. On 64-bit HMODULE will be 8 bytes but int will stay 4 bytes, so you're heading into trouble.

And you call is invalid:
SYSTEM_TIMEINFORMATION
You can't pass a type as argument.

*SysTimeInfo
SysTimeInfo is not a pointer you can dereference. Do you want to pass the address of SysTimeInfo? The you must do
&SysTimeInfo

The return at the end is not necessary. You don't return a value and it is the last instruction.

[Cmdr0Sunburn]

if you would read the code you sould see that i am passing a HINSTANCE__ to the getprocaddress. thats what my compiler said it needed to be.if i NtQuerySystemInformation = GetProcAddress(...) i get a huge list of errors, my compiler doesnt like that.NtQuerySystemInformation is a int. and i do need to return at the end or my function will fall through. i dont need to return a value.

[The Hobo]

Originally posted by Cmdr0Sunburn
if you would read the code you sould see that i am passing a HINSTANCE__ to the getprocaddress. thats what my compiler said it needed to be.if i NtQuerySystemInformation = GetProcAddress(...) i get a huge list of errors, my compiler doesnt like that.NtQuerySystemInformation is a int. and i do need to return at the end or my function will fall through. i dont need to return a value.

Your function will return at the end automatically if it was not instructed to do so before the end. Your code is just redundant.

[Cmdr0Sunburn]

Originally posted by The Hobo
Your function will return at the end automatically if it was not instructed to do so before the end. Your code is just redundant.

thats not what i was told in this c++ book, if you dont put a return, it will fall throught to the next block or function.

[parksie]

No, it'll fall through to the next block within a function. Once it hits the end of the function it will automatically return anyway.

[CornedBee]

Sorry, I confused retr and retrh

HINSTANCE and HMODULE are both typedefs of HINSTANCE__ *, use them instead as HINSTANCE__ is just a helper construct to guarantee type safety for handles (and is unavailable if you #define NOSTRICT before you include <windows.h>)

And you NtQuerySystemInformation call reamins invalid.

[Cmdr0Sunburn]

Originally posted by CornedBee
Sorry, I confused retr and retrh

HINSTANCE and HMODULE are both typedefs of HINSTANCE__ *, use them instead as HINSTANCE__ is just a helper construct to guarantee type safety for handles (and is unavailable if you #define NOSTRICT before you include <windows.h>)

And you NtQuerySystemInformation call reamins invalid.

i know its invalid, ill deal with that later as soon as i get it to say thats its invalid function, right now it saz it isnt one at all.

[CornedBee]

Ok, so again, how do you define NtQuerySystemInformation?

[Cmdr0Sunburn]

thanks all, thanks a lot.!!!!!!!!!!!!!!!!!!!!!!!!!!! i got it to work. i found a c++ project that egts the cpu time.