LIBPATH

LIBPATH attempts to find out the value of the LIBPATH environment 
variable. This cannot be returned from the regular environment SET 
command, or a DosQuery...API. Occasionally the LIBPATH variable is a 
handy thing to know. So, a not-so-clean solution is to find the value of 
the boot drive, find the CONFIG.SYS file, and attempt to extract the 
LIBPATH string from that file. This will only work in a case where there 
have been no previous changes to the CONFIG.SYS file since the system 
ha been booted, and specifically no direct manipulations of the LIBPATH 
value. Although this example is a crude kluge, the method can actually be 
useful on a number of occasions.

***********************************************************
*                       LIBPATH.C                         *
***********************************************************

#define INCL_DOSFILEMGR
#define INCL_DOSMISC

#include <os2.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#define CONFIG_FILE              "?:\\CONFIG.SYS"
#define LIBPATH                  "LIBPATH"
#define CR                       13
#define LF                       10

INT main ( VOID )
{
   APIRET         arReturn ;
   ULONG          ulDrive;
   PCHAR          pchFile ;
   HFILE          hfFile ;
   ULONG          ulAction ;
   ULONG          ulBytesRead ;
   PCHAR          pchBuffer ;
   PCHAR          pchLibpath ;
   USHORT         usIndex ;
   FILESTATUS3    fsStatus ;

   pchBuffer = NULL ;

   arReturn = DosQuerySysInfo ( QSV_BOOT_DRIVE,
                                QSV_BOOT_DRIVE,
                                &ulDrive,
                                sizeof ( ulDrive )) ;

   pchFile = CONFIG_FILE ;
   pchFile [0] = ulDrive + 'A' - 1 ;

   arReturn = DosQueryPathInfo ( pchFile,
                                 FIL_STANDARD,
                                 &fsStatus,
                                 sizeof ( fsStatus )) ;

   pchBuffer = malloc ( fsStatus.cbFile ) ;

   arReturn = DosOpen ( pchFile,
                        &hfFile,
                        &ulAction,
                        0,
                        FILE_NORMAL,
                        FILE_OPEN,
                        OPEN_FLAGS_FAIL_ON_ERROR |
                        OPEN_FLAGS_SEQUENTIAL |
                        OPEN_SHARE_DENYNONE |
                        OPEN_ACCESS_READONLY,
                        NULL ) ;

   arReturn = DosRead ( hfFile,
                        pchBuffer,
                        fsStatus.cbFile,
                        &ulBytesRead ) ;

   arReturn = DosClose ( hfFile ) ;

   pchBuffer [fsStatus.cbFile] = 0 ;

   pchLibpath = strstr ( pchBuffer, LIBPATH ) ;

   if (pchLibpath == NULL){
   /*will only execute this section of code if LIBPATH is NOT all caps*/
      for ( usIndex = 0; usIndex < strlen (pchBuffer); usIndex++){
      if (toupper(pchBuffer[usIndex]) == 'L')
         if (toupper(pchBuffer[usIndex+1]) == 'I' &&
             toupper(pchBuffer[usIndex+2]) == 'B' &&
             toupper(pchBuffer[usIndex+3]) == 'P' &&
             toupper(pchBuffer[usIndex+4]) == 'A' &&
             toupper(pchBuffer[usIndex+5]) == 'T' &&
             toupper(pchBuffer[usIndex+6]) == 'H'){
           pchLibpath = pchBuffer + usIndex;
           break;
         }
      }
   }

   for ( usIndex = 0 ; usIndex < CCHMAXPATHCOMP ; usIndex++ ){
      if ( pchLibpath [usIndex] == CR ){
         if ( pchLibpath [usIndex + 1] == LF )
         break ;
      } /* endif */
   } /* endfor */

   pchLibpath [usIndex] = 0 ;
   printf ( "\n%s\n", pchLibpath ) ;
   free ( pchBuffer ) ;
   return arReturn ;
}

***********************************************************
*                       LIBPATH.MAK                       *
***********************************************************

LIBPATH.EXE:                    LIBPATH.OBJ
        LINK386 @<<
LIBPATH
LIBPATH
LIBPATH
OS2386
LIBPATH
<<

LIBPATH.OBJ:                    LIBPATH.C
        ICC -C+ -Kb+ -Ss+ LIBPATH.C

***********************************************************
*                       LIBPATH.DEF                       *
***********************************************************

NAME LIBPATH WINDOWCOMPAT NEWFILES
DESCRIPTION 'LIBPATH Example
             Copyright (c) 1993 by Arthur Panov
             All rights reserved.'
PROTMODE

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+                       NOTICE                            +
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
The LIBPATH example is from The Art of OS/2 C Programming 
by Kathleen Panov, Arthur Panov, and Larry Salomon, Jr.,
August 1993, published by QED Publishing Group,
ISBN 0-89435-446-9. The example was uploaded by the
publisher with the assistance of the authors for use by 
Forum members. Please address comments to QED at 76620,2720.