FileExist question

[brixton]

Hey all,

Is there any FileExist function?  I can't see it in WIN32.HLP, and it would be really great if I could even use wildcards with this.  For example, if there are any .bak files present, delete them all.  I can achieve the same effect via batch files, but it's very messy.  Any help appreciated!

Thanks,

-brixton

[Ossa]

No, I havn't seen one, but this will tell you if a file exists:

Code Select Expand

FileExists PROC pszFile:DWORD

invoke CreateFile, pszFile, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, NULL

.if eax!=INVALID_HANDLE_VALUE
invoke CloseHandle, eax

; return TRUE

mov eax, TRUE
ret
.endif

; return FALSE

xor eax, eax
ret
FileExists ENDP

If you need to use wild cards, try using the FindFirstFile, FindNextFile and FindClose combination.

Ossa

[P1]

In the MASM32 Library there is:

exist

exist proc lpszFileName:DWORD

Description
This function tests if a file exists at the path and file name in the zero terminated string.

Parameter

1.   lpszFileName The zero terminated string that has the path & name of the file to test.

Return Value
If the return value in eax is zero, the file does not exist, if it is 1, then it exists.

Regards,  P1  :8)

[brixton]

Hey P1, long time, no chat.

I don't think I can use wildcards with the MASM32 'exist' procedure, but it's a useful one for other situations!
For the record, Ossa's FindFirstFile is absolutely perfect.  There's only 1 of the specified filetype, but I don't know the filename.  GetFirstFile works perfectly using *.bak (for example). 

Thanks for your interest,

-brixton

[P1]

Hey P1, long time, no chat.

Well, will you look at that.  It's an antique british chatter.  A rare find mate.  Back from ....   :green2

Regards,  P1  :8)

[brixton]

I don't think I understand your humour but..  Right back at ya  :dance:  :lol

Got the problem solved by-the-way, I had some problems because I didn't FindClose so eventually the search handle went to the roof until it resulted in an error - thus claiming a file didn't exist when it really did (I was checking for -1 on return).

[The Svin]

Code Select Expand


exist proc lpszFileName:DWORD

    LOCAL wfd :WIN32_FIND_DATA

    invoke FindFirstFile,lpszFileName,ADDR wfd
    invoke FindClose,eax
    ret

exist endp

If file isn't found FindFirstFile would return - 1 and passin - 1 to FindClose would lead that it returns 0. Otherwise FindClose would return 1.

[Ossa]

If file isn't found FindFirstFile would return - 1 and passin - 1 to FindClose would lead that it returns 0. Otherwise FindClose would return 1.

:eek Wow... nice solution.  :clap:

Ossa

[Ian_B]

Otherwise FindClose would return 1.

Much as I hate to contradict The Svin, officially it will return non-zero, not 1. The API doesn't guarantee a particular non-zero result, even if one usually occurs across most versions of Windows. Assuming a return value of 1 may not work in the next Windows version.

Ian_B

[The Svin]

Well, it doesn't change anything :)
then the proc (exist) returns zero if file doesn't exist and non zero if exits ;)

[evlncrn8]

totally easier to just to GetFileAttributes.. if it doesnt exist, the return is -1, if it passes, then check the return value to see if its a folder or whatnot...

[Ian_B]

That won't work with wildcards, though, which was part of brixton's original specification of the problem. Thanks for pointing this out, though, it is indeed a valid alternative if you have a particular filename to check.

[brixton]

Hey all, thanks for the interesting reading.

Eventually I settled on

Code Select Expand

..
@@:

      push 10
    call Sleep
      push OFFSET findfirstfilestruct
      push OFFSET existrule
    call FindFirstFile
      cmp eax, -1
  je @F
      push eax
    call FindClose
  jmp @B

@@:
...

This is perfect as existrule is a string like this: existrule BYTE "c:\ollydbg\*.bak*, 0
My app has to wait until there are no bak files, until it does something.

[P1]

Code Select Expand

  jmp @BEndless loop, if the file exists.  No timeouts, no warnings, just a stuck program.  You must have a better memory than me.  Or do you have super users?

Regards,  P1  :8)

[PBrennick]

Yes,
That is what he said...

My app has to wait until there are no bak files, until it does something.

Paul