函数名: abort

功 能: 异常终止一个进程

用 法: void abort(void);

程序例:

#include 
  
    
#include 
   
     int main(void) { printf("Calling abort()\n"); abort(); return 0; /* This is never reached */ } 
   
  

函数名: abs

功 能: 求整数的绝对值

用 法: int abs(int i);

程序例:

#include 
  
    
#include 
   
     int main(void) { int number = -1234; printf("number: %d absolute value: %d\n", number, abs(number)); return 0; } 
   
  

函数名: absread, abswirte

功 能: 绝对磁盘扇区读、写数据

用 法: int absread(int drive, int nsects, int sectno, void *buffer);

 int abswrite(int drive, int nsects, in tsectno, void *buffer); 

程序例:

/* absread example */ 
#include 
  
    
#include 
   
     #include 
    
      #include <
     dos.h> int main(void) { int i, strt, ch_out, sector; char buf[512]; printf("Insert a diskette into drive A and press any key\n"); getch(); sector = 0; if (absread(0, 1, sector, &buf) != 0) { perror("Disk problem"); exit(1); } printf("Read OK\n"); strt = 3; for (i=0; i<80; i++) { ch_out = buf[strt+i]; putchar(ch_out); } printf("\n"); return(0); } 
    
   
  

函数名: access

功 能: 确定文件的访问权限

用 法: int access(const char *filename, int amode);

程序例:

#include 
  
    
#include 
   
     int file_exists(char *filename); int main(void) { printf("Does NOTEXIST.FIL exist: %s\n", file_exists("NOTEXISTS.FIL")   "YES" : "NO"); return 0; } int file_exists(char *filename) { return (access(filename, 0) == 0); } 
   
  

函数名: acos

功 能: 反余弦函数

用 法: double acos(double x);

程序例:

#include 
  
    
#include 
   
     int main(void) { double result; double x = 0.5; result = acos(x); printf("The arc cosine of %lf is %lf\n", x, result); return 0; } 
   
  

函数名: allocmem

功 能: 分配DOS存储段

用 法: int allocmem(unsigned size, unsigned *seg);

程序例:

#include 
  
    
#include 
   
     #include 
    
      int main(void) { unsigned int size, segp; int stat; size = 64; /* (64 x 16) = 1024 bytes */ stat = allocmem(size, &segp); if (stat == -1) printf("Allocated memory at segment: %x\n", segp); else printf("Failed: maximum number of paragraphs available is %u\n", stat); return 0; } 
    
   
  

函数名: arc

功 能: 画一弧线

用 法: void far arc(int x, int y, int stangle, int endangle, int radius);

程序例:

#include 
  
    
#include 
   
     #include 
    
      #include 
     
       int main(void) { /* request auto detection */ int gdriver = DETECT, gmode, errorcode; int midx, midy; int stangle = 45, endangle = 135; int radius = 100; /* initialize graphics and local variables */ initgraph(&gdriver, &gmode, ""); /* read result of initialization */ errorcode = graphresult(); /* an error occurred */ if (errorcode != grOk) { printf("Graphics error: %s\n", grapherrormsg(errorcode)); printf("Press any key to halt:"); getch(); exit(1); /* terminate with an error code */ } midx = getmaxx() / 2; midy = getmaxy() / 2; setcolor(getmaxcolor()); /* draw arc */ arc(midx, midy, stangle, endangle, radius); /* clean up */ getch(); closegraph(); return 0; } 
     
    
   
  

函数名: asctime

功 能: 转换日期和时间为ASCII码

用 法: char *asctime(const struct tm *tblock);

程序例:

#include 
  
    
#include 
   
     #include 
    
      int main(void) { struct tm t; char str[80]; /* sample loading of tm structure */ t.tm_sec = 1; /* Seconds */ t.tm_min = 30; /* Minutes */ t.tm_hour = 9; /* Hour */ t.tm_mday = 22; /* Day of the Month */ t.tm_mon = 11; /* Month */ t.tm_year = 56; /* Year - does not include century */ t.tm_wday = 4; /* Day of the week */ t.tm_yday = 0; /* Does not show in asctime */ t.tm_isdst = 0; /* Is Daylight SavTime; does not show in asctime */ /* converts structure to null terminated string */ strcpy(str, asctime(&t)); printf("%s\n", str); return 0; } 
    
   
  

函数名: asin

功 能: 反正弦函数

用 法: double asin(double x);

程序例:

#include 
  
    
#include 
   
     int main(void) { double result; double x = 0.5; result = asin(x); printf("The arc sin of %lf is %lf\n", x, result); return(0); } 
   
  

函数名: assert