harbour-core/harbour/contrib/libnf/getenvrn.c

/*
 * $Id$
 */

/*
 * File......: GETENVRN.C
 * Author....: Rick Whitt
 * CIS ID....: 70672,605
 *
 * This is an original work by Rick Whitt and is placed in the
 * public domain.
 *
 * Modification history:
 * ---------------------
 *    Rev 1.2a  09 Sep 1996            JO
 * Added underscore prefix to environ() calls for MSC 8.0
 * Note: 5.2e version will work if linked with MSC OldNames.lib
 *
 *    Rev 1.2   01 Jan 1996 03:01:00   TED
 * Added prototypes to kill compiler warning.
 *
 *    Rev 1.1   15 Aug 1991 23:08:42   GLENN
 * Forest Belt proofread/edited/cleaned up doc
 *
 *    Rev 1.0   17 Jul 1991 22:08:12   GLENN
 * Initial revision.
 *
 */


/*  $DOC$
 *  $FUNCNAME$
 *     FT_GETE()
 *  $CATEGORY$
 *     Environment
 *  $ONELINER$
 *     Return the entire current environment
 *  $SYNTAX$
 *     FT_GETE( [ @<xReceiveVar> ] ) -> nNumStrings
 *  $ARGUMENTS$
 *     <xReceiveVar> is the variable to receive the environment data.
 *
 *     <xReceiveVar> can be a character type variable, in which case
 *     the function will place all environment strings in the variable
 *     separated by carriage return/line feeds (chr 13 + chr(10)).
 *
 *     <xReceiveVar> can be an array type, in which case the function
 *     will place each string in an array element.  The array MUST be
 *     declared with the proper number of elements prior to passing it
 *     to the function.  This can be done by calling FT_GETE() without
 *     parameters first to get the number of strings in the environment.
 *
 *     Note that the argument MUST be passed by reference. Since arrays
 *     are by nature passed by reference, the "@" symbol is optional when
 *     passing an array.
 *
 *     If no argument is passed, FT_GETE() merely returns the number
 *     of strings in the environment.
 *  $RETURNS$
 *     FT_GETE() returns the total number of strings found in the
 *     current program's environment.
 *  $DESCRIPTION$
 *     This function stores ALL of the current program's environment
 *     variables in either a block of text lines or in an array.  It is
 *     useful for looking at the entire environment at once, or recording
 *     a snapshot of it to a file for later inspection, such as when a
 *     program error occurs.  If the value of ONE SPECIFIC variable is
 *     desired, use Clipper's built-in GETE() function.
 *
 *     This function uses the undocumented internal variable "_environ",
 *     as well as the functions _strcpy(), _strcat(), and _strlen() from
 *     CLIPPER.LIB
 *  $EXAMPLES$
 *     Get the environment in text form and browse it:
 *
 *        cEnvBlock   := ""
 *        nNumStrings := FT_GETE(@cEnvBlock)
 *        @  0, 0 to MAXROW() - 1, MAXCOL()
 *        @  MAXROW(), 0 say 'Browse strings, press ESC to exit...'
 *        MEMOWRIT(cEnvBlock, 1, 1, MAXROW() - 2,MAXCOL() - 1, .F.)
 *
 *     Get the environment in text form and write it to a file:
 *
 *        cEnvBlock := ""
 *        FT_GETE(@cEnvBlock)
 *        MEMOWRIT("ENVIRON.TXT", cEnvBlock)
 *
 *     Get the environment in Array form:
 *
 *        aEnvArray := ARRAY(FT_GETE())
 *        FT_GETE(aEnvArray)
 *        ? aEnvArray[1]       // "COMSPEC=C:\COMMAND.COM"
 *        ? aEnvArray[2]       // "PATH=C:\;C:\DOS;C:\UTIL;C:\CLIP50\BIN"
 *          ... etc ...
 *  $END$
 */

/* NOTE: we need this to prevent base types redefinition */
#define _CLIPDEFS_H

#include <extend.api>
#include <fm.api>

#define NORETURN   0
#define CHARTYPE   1
#define ARRAYTYPE  2
#define CRLF       "\x0D\x0A"
/*
unsigned int strlen( char * );
char * strcpy( char *, char * );
char * strcat( char *, char * );
*/
HB_FUNC(FT_GETE)
{
    /* INTERNALS WARNING: All references to 'environ', strlen(), ;
       strcpy(), and strcat() are undocumented Clipper 5.0 internals.
    */
#if defined(HB_OS_DOS) || defined(HB_OS_WIN_32)
   {

    extern char **_environ;
    char *buffer = NULL;
    int x;
    int buffsize = 0;
    int rettype  = NORETURN;

    if (ISCHAR(1))
        rettype = CHARTYPE;
    if (ISARRAY(1))
        rettype = ARRAYTYPE;

    if (rettype == CHARTYPE)
        // scan strings first and add up total size
        {
        for (x = 0; ;x++)
            {
            if (! _environ[x])
                // null string, we're done
                break;
            // add length of this string plus 2 for the crlf
            buffsize += (strlen(_environ[x]) + 2);
            }
        // add 1 more byte for final nul character
        buffsize++;

        //  now allocate that much memory and make sure 1st byte is a nul
        buffer = ( char * ) hb_xalloc(buffsize);
        strcpy(buffer,"\0");
        }

    for (x = 0; ;x++)
        {
        if (! _environ[x])
            // null string, we're done
            break;

        if (rettype == CHARTYPE)
            {
            // tack string onto end of buffer
            strcat( buffer, _environ[x] );
            // add crlf at end of each string
            strcat( buffer, CRLF );
            }

        if (rettype == ARRAYTYPE)
            // store string to next array element
            hb_storc(_environ[x],1,x + 1);

        }

    if (rettype == CHARTYPE)
        {
        // return buffer to app and free memory
        hb_storc(buffer,1);
        hb_xfree(buffer);
        }

    // return number of strings found
    hb_retni(x);
}
#endif
}