C语言的函数!

内财数模协会

<>函数名: signal
功  能: 设置某一信号的对应动作
用  法: int signal(int sig, sigfun fname);
程序例: <>/* This example installs a signal handler routine for SIGFPE,
   catches an integer overflow condition, makes an adjustment
   to AX register, and returns. This example program MAY cause
   your computer to crash, and will produce runtime errors
   depending on which memory model is used.
*/ <>#pragma inline
#include &lt;stdio.h&gt;
#include &lt;signal.h&gt; <P>void Catcher(int sig, int type, int *reglist)
{
   printf("Caught it!\n");
   *(reglist + 8) = 3;             /* make return AX = 3 */
} <P>int main(void)
{
   signal(SIGFPE, Catcher);
   asm     mov     ax,07FFFH       /* AX = 32767 */
   asm     inc     ax              /* cause overflow */
   asm     into                    /* activate handler */ <P>   /* The handler set AX to 3 on return. If that hadn't happened,
      there would have been another exception when the next 'into'
      was executed after the 'dec' instruction. */
   asm     dec     ax              /* no overflow now */
   asm     into                    /* doesn't activate */
   return 0;
}
  
</P>

内财数模协会

<>函数名: sin
功  能: 正弦函数
用  法: double sin(double x);
程序例: <>#include &lt;stdio.h&gt;
#include &lt;math.h&gt; <>int main(void)
{
   double result, x = 0.5; <P>   result = sin(x);
   printf("The sin() of %lf is %lf\n", x, result);
   return 0;
}
</P>

内财数模协会

<>函数名: sinh
功  能: 双曲正弦函数
用  法: double sinh(double x);
程序例: <>#include &lt;stdio.h&gt;
#include &lt;math.h&gt; <>int main(void)
{
   double result, x = 0.5; <P>   result = sinh(x);
   printf("The hyperbolic sin() of %lf is %lf\n", x, result);
   return 0;
}
</P>

内财数模协会

<>函数名: sleep
功  能: 执行挂起一段时间
用  法: unsigned sleep(unsigned seconds);
程序例: <>#include &lt;dos.h&gt;
#include &lt;stdio.h&gt; <>int main(void)
{
   int i; <P>   for (i=1; i&lt;5; i++)
   {
      printf("Sleeping for %d seconds\n", i);
      sleep(i);
   }
   return 0;
}
  
</P>

内财数模协会

<>函数名: sopen
功  能: 打开一共享文件
用  法: int sopen(char *pathname, int access, int shflag, int permiss);
程序例: <>#include &lt;io.h&gt;
#include &lt;fcntl.h&gt;
#include &lt;sys\stat.h&gt;
#include &lt;process.h&gt;
#include &lt;share.h&gt;
#include &lt;stdio.h&gt; <>int main(void)
{
   int handle;
   int status; <P>   handle = sopen("c:\\autoexec.bat", O_RDONLY, SH_DENYNO, S_IREAD); <P>   if (!handle)
   {
      printf("sopen failed\n");
      exit(1);
   } <P>   status = access("c:\\autoexec.bat", 6);
   if (status == 0)
      printf("read/write access allowed\n");
   else
      printf("read/write access not allowed\n"); <P>   close(handle);
   return 0;
}
  
  
</P>

内财数模协会

<>函数名: sound
功  能: 以指定频率打开PC扬声器
用  法: void sound(unsigned frequency);
程序例: <>/* Emits a 7-Hz tone for 10 seconds.
   Your PC may not be able to emit a 7-Hz tone. */
#include &lt;dos.h&gt; <>int main(void)
{
   sound(7);
   delay(10000);
   nosound();
   return 0;
}
</P>

内财数模协会

<>函数名: spawnl
功  能: 创建并运行子程序
用  法: int spawnl(int mode, char *pathname, char *arg0,
     arg1, ... argn, NULL);
程序例: <>#include &lt;process.h&gt;
#include &lt;stdio.h&gt;
#include &lt;conio.h&gt; <>int main(void)
{
   int result; <P>   clrscr();
   result = spawnl(P_WAIT, "tcc.exe", NULL);
   if (result == -1)
   {
      perror("Error from spawnl");
      exit(1);
   }
   return 0;
}
  
</P>

内财数模协会

<>函数名: spawnle
功  能: 创建并运行子程序
用  法: int spawnle(int mode, char *pathname, char *arg0,
      arg1,..., argn, NULL);
程序例: <>/* spawnle() example */ <>#include &lt;process.h&gt;
#include &lt;stdio.h&gt;
#include &lt;conio.h&gt; <P>int main(void)
{
   int result; <P>   clrscr();
   result = spawnle(P_WAIT, "tcc.exe", NULL, NULL);
   if (result == -1)
   {
      perror("Error from spawnle");
      exit(1);
   }
   return 0;
}
  
</P>

内财数模协会

<>函数名: sprintf
功  能: 送格式化输出到字符串中
用  法: int sprintf(char *string, char *farmat [,argument,...]);
程序例: <>#include &lt;stdio.h&gt;
#include &lt;math.h&gt; <>int main(void)
{
   char buffer[80]; <P>   sprintf(buffer, "An approximation of Pi is %f\n", M_PI);
   puts(buffer);
   return 0;
}
  
</P>

内财数模协会

<>函数名: sqrt
功  能: 计算平方根
用  法: double sqrt(double x);
程序例: <>#include &lt;math.h&gt;
#include &lt;stdio.h&gt; <> int main(void)
{
    double x = 4.0, result; <P>    result = sqrt(x);
    printf("The square root of %lf is %lf\n", x, result);
    return 0;
}
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