Reading Files

[ASingerMustDie]

Hi All

Sorry to bother you with something surely so trivial...

I am attempting to read the first 4 bytes of a file and ensuring that it reads "RIFF" (perhaps for obvious reasons).

I am using ReadFile to achieve this, the problem being that the buffer I read into seems to have an extra (null?) character appended to it, or so it appears when I attempt to debug. I know that character arrays are terminated by a null character, but if this is what is happening, how do I then compare the buffer to the string "RIFF"?

The code I have is (chopped for ease of reading)...

char waveBuffer[4];
DWORD waveRead;
HANDLE waveHandle;

//Assume file is opened

ReadFile(waveHandle, &waveBuffer, 4, &waveRead, NULL);
if (!strcmp(waveBuffer, "RIFF&quot)
{
//Is Good;
}
else
{
//Is not good
}

I cant manage to have it work for files that DO begin with the four characters RIFF. Why is this?

Any help would be most appreciated.

ASMD

PS And why-oh-why when I opt to click the Help menu am I told that a required component is missing and that I must reinstall?

 

[Renitha]

Before using strcmp(..) the buffer should be copied to a exact string. ReadFile gives the buffer and no. of chracters read in " waveRead".SO don't use buffer to string compare directly.

 

[ASingerMustDie]

Ahhhhhhhhh...thanks a great deal

 

[ASingerMustDie]

OK...all of a sudden I feel like I need my hand held...
I tried to copy the buffer thus:

char waveHead[4];

//Open and read file

strcpy(waveHead, waveBuffer);

But this not only crashed the program but the entire computer...it has been so long since I dabbled in C++.

Thanks for the help so far and any subsequent aid.
ASMD

 

[Renitha]

ok, Just add this line after ReadFile(...)

waveBuffer[waveRead]='\0';

if (!strcmp(waveBuffer, "RIFF&quot)
{
.............
}

 

[gzJungle]

Why not try like this:
strncmp(waveBuffr,"RIFF",4); ?

 

[ASingerMustDie]

Thanks all

You've been most helpful, problem sorted.