topic Re: Problem with CreateProcess in Software Archive

Problem with CreateProcess

grtoro — Thu, 08 Nov 2001 07:09:35 GMT

My Quickwin program makes repeated calls to another program (which runs minimized) using CreateProcess. I followed the "startp" sample in the samples directory. I have noticed the following sequence of events:

a) During the second and later calls, CreateProcess returns a .false. value, although the called program has executed properly. My program then calls GetLastError, which returns zero (i.e., ERROR_SUCCESS (great name!)).

b) The call to CloseHandle(pi%hThread) returns 0 (error) and a call to GetLast Error returns 6 (ERROR_INVALID_HANDLE).

c) The call to WaitForSingleObject(pi%hProcess, -1) returns -1 and and a call to GetLast Error also returns 6.

d) The call to CloseHandle(pi%hProcess) returns 0 (error) and a call to GetLast Error also returns 6.

In spite of this, the calling and called program seem to be working OK, although I suspect there may be a large memory leak (I have had to reboot once). I have checked all non_null arguments to CreateProcess and nothing changes between the first and later calls. In particular, dwCreate is 144, si is zero except for si%CB=68,
si%DWFLAGS=1, si%WSHOWWINDOW=6, and pi is all zeros.

Does anyone have any suggestion on how to correct this problem?

Thanks,

Gabriel

Re: Problem with CreateProcess

Jugoslav_Dujic — Thu, 08 Nov 2001 07:53:13 GMT

Hmm, something is really fishy here. Could you post some relevant code please, especially CreateProcess part? (please enclose code in

...

HTML tags when posting so that it won't be screwed by Forum sogtware). Looks as if something is different in second call to CreateProcess but I cannot figure out why.

Jugoslav

Re: Problem with CreateProcess

grtoro — Thu, 08 Nov 2001 08:15:13 GMT

 
  ! for createProcess 
 
  integer      res 
  character    szArgs*512                       ! new process arguments buffer & temp pointer 
  character                   DirName*512             ! current DirName for new process 
  character                   szPgmName*(MAX_PATH)    ! name of the program 
  logical(4)                  fSuccess                ! API return code 
  type(T_STARTUPINFO)         si                      ! used for CreateProcess 
  type(T_PROCESS_INFORMATION) pi                      ! used for CreateProcess 
   
  logical(4)                  bMoreParams     ! flag end of new process parameter processing 
  logical(4)                  bWait           ! wait/no wait for new process to end 
  integer                     dwResult        ! API return code 
  integer                     dwCreate        ! new process creation flags 
  integer                     bExtension      ! input filename have an explicit extension? 
  integer                     SIZEOFSTARTUPINFO 
  integer                     SIZESECURITYATTRIBUTES 
 ! integer                     i 
  character*5                 aExt(4) 
  type(T_SECURITY_ATTRIBUTES) sa, sb 
  data DirName /'0'/ 
. 
. 
. 
 
! run gs using create process 
  dwCreate = CREATE_NEW_CONSOLE 
  dwCreate = IOR(HIGH_PRIORITY_CLASS,dwCreate)!  
 
  SIZEOFSTARTUPINFO = 68 
  call ZeroMemory (LOC (si), SIZEOFSTARTUPINFO) 
  si%cb= SIZEOFSTARTUPINFO 
  !pi=T_PROCESS_INFORMATION(0,0,0,0)   ! 4 integer*4 quantities 
  PI%hProcess =0  
  PI%hThread =0  
  PI%dwProcessId =0  
  PI%dwThreadId =0  
   
 
  !minimized 
   si%wShowWindow = SW_MINIMIZE 
   si%dwFlags = IOR(STARTF_USESHOWWINDOW, si%dwFlags) 
  !maximized 
 ! si%wShowWindow = SW_SHOWMAXIMIZED 
 ! si%dwFlags = IOR (STARTF_USESHOWWINDOW, si%dwFlags) 
 
  bWait=.true. 
 
  SIZESECURITYATTRIBUTES = 12 
  sa%nLength = SIZESECURITYATTRIBUTES 
  sa%lpSecurityDescriptor = NULL 
  sa%bInheritHandle = .true. 
 
!  IF ( .not. DlgInit( IDD_MAY_TAKE_TIME , dlg_modeless ) ) THEN 
!    WRITE (6,*) "Error: dialog not found: IDD_MAY_TAKE_TIME" 
!  ENDIF 
!  istat = DlgModeless( dlg_modeless ) 
   
  fSuccess=.true. 
 !note: GS_CMD and GS_LIB are always read from the same file and do not change  
 fSuccess = CreateProcess( & 
       TRIM(GS_CMD)//CHAR(0),    &                     ! image file name 
       TRIM(GS_LIB)//' @tree_tmp.gs'//CHAR(0), &       ! command line (including program name) 
                 NULL_security_attributes,      &  ! security for process 
                 NULL_security_attributes,      &  ! security for main thread 
                 .FALSE.,                       &  ! new process inherits handles? 
                 dwCreate,                      &  ! creation flags 
                 NULL,                          &  ! environment 
                 null_character,                &  ! new current DirName 
                 si,                            &  ! STARTUPINFO structure 
                 pi)                               ! PROCESSINFORMATION structure 
 
    if (fSuccess .EQV. .FALSE.) then 
        lasterror=GetLastError() 
        select case (lasterror)              !  process common errors 
            case ( ERROR_SUCCESS )  ! great name! 
                continue 
          
      WRITE(6,*)'fsuccess was false but GetlastError returns 0' 
            case (ERROR_FILE_NOT_FOUND) 
                write (6,*) "Error: Ghostscript program not found" 
                !CALL DlgExit( dlg_modeless ) 
                !CALL DlgUninit( dlg_modeless ) 
                RETURN 
            case (ERROR_DIRECTORY) 
                write (6,*)("Error calling Ghostscript: bad starting directory") 
                !CALL DlgExit( dlg_modeless ) 
                !CALL DlgUninit( dlg_modeless ) 
                RETURN 
            case (ERROR_PATH_NOT_F

Re: Problem with CreateProcess

grtoro — Thu, 08 Nov 2001 08:35:30 GMT

 
  ! for createProcess 
 
  integer      res 
  character    szArgs*512                       ! new process arguments buffer & temp pointer 
  character                   DirName*512             ! current DirName for new process 
  character                   szPgmName*(MAX_PATH)    ! name of the program 
  logical(4)                  fSuccess                ! API return code 
  type(T_STARTUPINFO)         si                      ! used for CreateProcess 
  type(T_PROCESS_INFORMATION) pi                      ! used for CreateProcess 
   
  logical(4)                  bMoreParams     ! flag end of new process parameter processing 
  logical(4)                  bWait           ! wait/no wait for new process to end 
  integer                     dwResult        ! API return code 
  integer                     dwCreate        ! new process creation flags 
  integer                     bExtension      ! input filename have an explicit extension? 
  integer                     SIZEOFSTARTUPINFO 
  integer                     SIZESECURITYATTRIBUTES 
 ! integer                     i 
  character*5                 aExt(4) 
  type(T_SECURITY_ATTRIBUTES) sa, sb 
  data DirName /'0'/ 
. 
. 
. 
 
! run gs using create process 
  dwCreate = CREATE_NEW_CONSOLE 
  dwCreate = IOR(HIGH_PRIORITY_CLASS,dwCreate)!  
 
  SIZEOFSTARTUPINFO = 68 
  call ZeroMemory (LOC (si), SIZEOFSTARTUPINFO) 
  si%cb= SIZEOFSTARTUPINFO 
  !pi=T_PROCESS_INFORMATION(0,0,0,0)   ! 4 integer*4 quantities 
  PI%hProcess =0  
  PI%hThread =0  
  PI%dwProcessId =0  
  PI%dwThreadId =0  
   
 
  !minimized 
   si%wShowWindow = SW_MINIMIZE 
   si%dwFlags = IOR(STARTF_USESHOWWINDOW, si%dwFlags) 
  !maximized 
 ! si%wShowWindow = SW_SHOWMAXIMIZED 
 ! si%dwFlags = IOR (STARTF_USESHOWWINDOW, si%dwFlags) 
 
  bWait=.true. 
 
  SIZESECURITYATTRIBUTES = 12 
  sa%nLength = SIZESECURITYATTRIBUTES 
  sa%lpSecurityDescriptor = NULL 
  sa%bInheritHandle = .true. 
 
!  IF ( .not. DlgInit( IDD_MAY_TAKE_TIME , dlg_modeless ) ) THEN 
!    WRITE (6,*) "Error: dialog not found: IDD_MAY_TAKE_TIME" 
!  ENDIF 
!  istat = DlgModeless( dlg_modeless ) 
   
  fSuccess=.true. 
 !note: GS_CMD and GS_LIB are always read from the same file and do not change  
 fSuccess = CreateProcess( & 
       TRIM(GS_CMD)//CHAR(0),    &                     ! image file name 
       TRIM(GS_LIB)//' @tree_tmp.gs'//CHAR(0), &       ! command line (including program name) 
                 NULL_security_attributes,      &  ! security for process 
                 NULL_security_attributes,      &  ! security for main thread 
                 .FALSE.,                       &  ! new process inherits handles? 
                 dwCreate,                      &  ! creation flags 
                 NULL,                          &  ! environment 
                 null_character,                &  ! new current DirName 
                 si,                            &  ! STARTUPINFO structure 
                 pi)                               ! PROCESSINFORMATION structure 
 
    if (fSuccess .EQV. .FALSE.) then 
        lasterror=GetLastError() 
        select case (lasterror)              !  process common errors 
            case ( ERROR_SUCCESS )  ! great name! 
                continue 
          
      WRITE(6,*)'fsuccess was false but GetlastError returns 0' 
            case (ERROR_FILE_NOT_FOUND) 
                write (6,*) "Error: Ghostscript program not found" 
                !CALL DlgExit( dlg_modeless ) 
                !CALL DlgUninit( dlg_modeless ) 
                RETURN 
            case (ERROR_DIRECTORY) 
                write (6,*)("Error calling Ghostscript: bad starting directory") 
                !CALL DlgExit( dlg_modeless ) 
                !CALL DlgUninit( dlg_modeless ) 
                RETURN 
            case (ERROR_PATH_NOT_F

Re: Problem with CreateProcess

grtoro — Thu, 08 Nov 2001 08:52:15 GMT

continuation of code:

 
            case (ERROR_PATH_NOT_FOUND) 
                write (6,*) "Error calling Ghostscript: bad path" 
                !CALL DlgExit( dlg_modeless ) 
                !CALL DlgUninit( dlg_modeless ) 
                RETURN 
 
            case DEFAULT 
                 write (6,50) lasterror 
50               format ('Error  calling Ghostscript: GetLastError=',I5,' CreateProcess') 
                !CALL DlgExit( dlg_modeless ) 
                !CALL DlgUninit( dlg_modeless ) 
                RETURN 
        end select 
    end if 
 
    !  close pipe handle - child's instance will be closed when terminates 
    res= CloseHandle(pi%hThread) 
    if (res.eq.0) then 
      istat=GetLastError() 
    endif 
    if  (bWait .NEQV. .FALSE.) then !  wait /Wtime wait flag specified? 
      !   object to wait for 
      dwResult = WaitForSingleObject(pi%hProcess, -1) !  timeout time 
      if (dwResult == -1) then 
        write (6,150) GetLastError() 
150     format ('Error handling Ghostscript exit:  GetLastError=',I5,' WaitForSingleObject') 
      end if 
    end if 
    res= CloseHandle(pi%hProcess) !  close process handle or it won't die 
    if (res.eq.0) then 
      istat=GetLastError() 
    endif

Re: Problem with CreateProcess

Jugoslav_Dujic — Thu, 08 Nov 2001 19:03:47 GMT

I've pasted your code with minor changes (actually, I invoked cmd instead of GhostScript because I was lazy to investigate gs command line options and added an infinite loop instead of turning it into a subroutine) -- and it worked beautifully ;-). Btw, is it Win9x or NT/2000?

Jugoslav

Re: Problem with CreateProcess

grtoro — Thu, 08 Nov 2001 22:43:24 GMT

Jugoslav,

Thanks for your help. I am using W98 SE. Two things I want to add:

a) The Ghostscript program works fine every time, even when I get the (apparently spurious) error messages. I am mainly concerned with memory leaks that may be occuring.

b) After seemingly harmless changes to dirName and other variables from "startp" that appear to be unused, I am finding that the errors occur only occasionaly (not consistently) after the first time.

This is probably a problem my program can live with, but I would like to resolve it, especially because of the possibility of memory leaks.

Thanks again,

Gabriel