filetabl.c

不错书对C++/C程序员很有用的大家不要错过.

#include <stdio.h>
#include <dos.h>
#include <stdlib.h>

void main(void)
{
	struct fcbs
	{
		char drive;
		char filename[8];
		char extension[3];
		int current_block;
		int record_size;
	};
	typedef struct fcbs fcb;
	struct program_segment_prefix
	{
		char near *int20;
		char near *next_paragraph_segment;
		char reserved_1;
		char dos_dispatcher[5];
		char far *terminate_vector;
		char far *ctrlc_vector;
		char near *parent_psp;
		unsigned char file_table[20];
		char near *environment_block_segment;
		char far *stack_storage;
		int handles_available;
		char far *file_table_address;
		char far *shares_previous_psp;
		char reserved_2[20];
		char dos_int21_retf[3];
		char reserved_3[9];
		fcb fcb1;
		fcb fcb2;
		char reserved_4[4];
		char command_tail[128];
	} far *psp;
	int i;

	psp = (struct program_segment_prefix far *) ((long) _psp << 16);
	for (i = 0; i < 20; i++)
		printf("Entry %d contains %x\n", i, psp->file_table[i]);
}