c语言函数大全

墙角野猫

函数名: bdos
功 能: DOS系统调用
用 法: int bdos(int dosfun, unsigned dosdx, unsigned dosal);
程序例:
#include
#include
/* Get current drive as 'A', 'B', ... */
char current_drive(void)
{
char curdrive;
/* Get current disk as 0, 1, ... */
curdrive = bdos(0x19, 0, 0);
return('A' + curdrive);
}
int main(void)
{
printf("The current drive is %c:
", current_drive());
return 0;
}

墙角野猫

函数名: bdosptr
功 能: DOS系统调用
用 法: int bdosptr(int dosfun, void *argument, unsigned dosal);
程序例:
#include
#include
#include
#include
#include
#include
#define BUFLEN 80
int main(void)
{
char buffer[BUFLEN];
int test;
printf("Enter full pathname of a directory
");
gets(buffer);
test = bdosptr(0x3B,buffer,0);
if(test)
{
printf("DOS error message: %d
", errno);
/* See errno.h for error listings */
exit (1);
}
getcwd(buffer, BUFLEN);
printf("The current directory is: %s
", buffer);
return 0;
}

墙角野猫

函数名: bioscom
功 能: 串行I/O通信
用 法: int bioscom(int cmd, char abyte, int port);
程序例:
#include
#include
#define COM1 0
#define DATA_READY 0x100
#define TRUE 1
#define FALSE 0
#define SETTINGS ( 0x80 | 0x02 | 0x00 | 0x00)
int main(void)
{
int in, out, status, DONE = FALSE;
bioscom(0, SETTINGS, COM1);
cprintf("... BIOSCOM [ESC] to exit ...
");
while (!DONE)
{
status = bioscom(3, 0, COM1);
if (status & DATA_READY)
if ((out = bioscom(2, 0, COM1) & 0x7F) != 0)
putch(out);
if (kbhit())
{
if ((in = getch()) == '\x1B')
DONE = TRUE;
bioscom(1, in, COM1);
}
}
return 0;
}

墙角野猫

函数名: biosdisk
功 能: 软硬盘I/O
用 法: int biosdisk(int cmd, int drive, int head, int track, int sector
int nsects, void *buffer);
程序例:
#include
#include
int main(void)
{
int result;
char buffer[512];
printf("Testing to see if drive a: is ready
");
result = biosdisk(4,0,0,0,0,1,buffer);
result &= 0x02;
(result) ? (printf("Drive A: Ready
")) :
(printf("Drive A: Not Ready
"));
return 0;
}

墙角野猫

函数名: biosequip
功 能: 检查设备
用 法: int biosequip(void);
程序例:
#include
#include
int main(void)
{
int result;
char buffer[512];
printf("Testing to see if drive a: is ready
");
result = biosdisk(4,0,0,0,0,1,buffer);
result &= 0x02;
(result) ? (printf("Drive A: Ready
")) :
(printf("Drive A: Not Ready
"));
return 0;
}

墙角野猫

函数名: bioskey
功 能: 直接使用BIOS服务的键盘接口
用 法: int bioskey(int cmd);
程序例:
#include
#include
#include
#define RIGHT 0x01
#define LEFT 0x02
#define CTRL 0x04
#define ALT 0x08
int main(void)
{
int key, modifiers;
/* function 1 returns 0 until a key is pressed */
while (bioskey(1) == 0);
/* function 0 returns the key that is waiting */
key = bioskey(0);
/* use function 2 to determine if shift keys were used */
modifiers = bioskey(2);
if (modifiers)
{
printf("[");
if (modifiers & RIGHT) printf("RIGHT");
if (modifiers & LEFT) printf("LEFT");
if (modifiers & CTRL) printf("CTRL");
if (modifiers & ALT) printf("ALT");
printf("]");
}
/* print out the character read */
if (isalnum(key & 0xFF))
printf("'%c'
", key);
else
printf("%#02x
", key);
return 0;
}

墙角野猫

函数名: biosmemory
功 能: 返回存储块大小
用 法:int biosmemory(void);
程序例:
#include
#include
int main(void)
{
int memory_size;
memory_size = biosmemory(); /* returns value up to 640K */
printf("RAM size = %dK
",memory_size);
return 0;
}

墙角野猫

函数名: biosprint
功 能: 直接使用BIOS服务的打印机I/O
用 法: int biosprint(int cmd, int byte, int port);
程序例:
#include
#include
#include
int main(void)
{
#define STATUS 2 /* printer status command */
#define PORTNUM 0 /* port number for LPT1 */
int status, abyte=0;
printf("Please turn off your printer. Press any key to continue
");
getch();
status = biosprint(STATUS, abyte, PORTNUM);
if (status & 0x01)
printf("Device time out.
");
if (status & 0x08)
printf("I/O error.
");
if (status & 0x10)
printf("Selected.
");
if (status & 0x20)
printf("Out of paper.
");
if (status & 0x40)
printf("Acknowledge.
");
if (status & 0x80)
printf("Not busy.
");
return 0;
}

墙角野猫

函数名: biostime
功 能: 读取或设置BIOS时间
用 法: long biostime(int cmd, long newtime);
程序例:
#include
#include
#include
#include
int main(void)
{
long bios_time;
clrscr();
cprintf("The number of clock ticks since midnight is:\r
");
cprintf("The number of seconds since midnight is:\r
");
cprintf("The number of minutes since midnight is:\r
");
cprintf("The number of hours since midnight is:\r
");
cprintf("\r
Press any key to quit:");
while(!kbhit())
{
bios_time = biostime(0, 0L);
gotoxy(50, 1);
cprintf("%lu", bios_time);
gotoxy(50, 2);
cprintf("%.4f", bios_time / CLK_TCK);
gotoxy(50, 3);
cprintf("%.4f", bios_time / CLK_TCK / 60);
gotoxy(50, 4);
cprintf("%.4f", bios_time / CLK_TCK / 3600);
}
return 0;
}

墙角野猫

函数名: brk
功 能: 改变数据段空间分配
用 法: int brk(void *endds);
程序例:
#include
#include
int main(void)
{
char *ptr;
printf("Changing allocation with brk()
");
ptr = malloc(1);
printf("Before brk() call: %lu bytes free
", coreleft());
brk(ptr+1000);
printf(" After brk() call: %lu bytes free
", coreleft());
return 0;
}