src/backend/utils/misc/guc.c
int
gp_guc_list_show(struct StringInfoData    *buf,
                  const char               *pfx,
                  const char               *fmt,
                  GucSource                 excluding,
                  List                     *guclist)
{
    int         oldlen = buf->len;
    ListCell   *cell;
    char       *value;
    struct config_generic  *gconf;

   	foreach(cell, guclist)
	{
		gconf = (struct config_generic *)lfirst(cell);
		if (gconf->source > excluding)
        {
            if (pfx)
            {
                appendStringInfoString(buf, pfx);
                pfx = NULL;
            }
            value = _ShowOption(gconf, true);
            appendStringInfo(buf, fmt, gconf->name, value);
            pfree(value);
        }
	}
    return buf->len - oldlen;
}
/*
 * gp_guc_list_show
 *
 * Given a list of GUCs (a List of struct config_generic), appends the
 * option names and values to caller's buffer, skipping any whose
 * source <= 'excluding'.  The 'pfx' string is inserted at the
 * beginning.  The 'fmt' string must contain two occurrences of "%s",
 * which are expanded to the GUC name and value, respectively.
 *
 * Returns the length of the string appended to the buffer.
 */
gp_guc_list_show
Given a list of GUCs (a List of struct config_generic), appends the
option names and values to caller's buffer, skipping any whose
source <= 'excluding'.  The 'pfx' string is inserted at the
beginning.  The 'fmt' string must contain two occurrences of "%s",
which are expanded to the GUC name and value, respectively.

Returns the length of the string appended to the buffer.
gp_guc_list_show Given a list of GUCs ( a List of struct config_generic ) appends the option names and values to caller ' s buffer skipping any whose source < = ' excluding ' . The ' pfx ' string is inserted at the beginning . The ' fmt ' string must contain two occurrences of " %s " which are expanded to the GUC name and value respectively . Returns the length of the string appended to the buffer .
int
gp_guc_list_show(struct StringInfoData    *buf,
                  const char               *pfx,
                  const char               *fmt,
                  GucSource                 excluding,
                  List                     *guclist)
{
    int         oldlen = buf->len;
    ListCell   *cell;
    char       *value;
    struct config_generic  *gconf;
   	foreach(cell, guclist)
	{
		gconf = (struct config_generic *)lfirst(cell);
		if (gconf->source > excluding)
        {
            if (pfx)
            {
                appendStringInfoString(buf, pfx);
                pfx = NULL;
            }
            value = _ShowOption(gconf, true);
            appendStringInfo(buf, fmt, gconf->name, value);
            pfree(value);
        }
	}
    return buf->len - oldlen;
}
int gp_guc_list_show ( struct StringInfoData * buf , const char * pfx , const char * fmt , GucSource excluding , List * guclist ) { int oldlen = buf -> len ; ListCell * cell ; char * value ; struct config_generic * gconf ; foreach ( cell , guclist ) { gconf = ( struct config_generic * ) lfirst ( cell ) ; if ( gconf -> source > excluding ) { if ( pfx ) { appendStringInfoString ( buf , pfx ) ; pfx = NULL ; } value = _ShowOption ( gconf , true ) ; appendStringInfo ( buf , fmt , gconf -> name , value ) ; pfree ( value ) ; } } return buf -> len - oldlen ; }
gp_guc_list_show
 Given a list of GUCs (a List of struct config_generic), appends the
 option names and values to caller's buffer, skipping any whose
 source <= 'excluding'.
gp_guc_list_show Given a list of GUCs ( a List of struct config_generic ) appends the option names and values to caller ' s buffer skipping any whose source < = ' excluding ' .