c_info.txt

这是一个unix 系统下的 C 语言函数大全的电子文章。

      程序例: 

      /* execv example */ 
      #include <process.h> 
      #include <stdio.h> 
      #include <errno.h> 

      void main(int argc, char *argv[]) 
      { 
      int i; 

      printf("Command line arguments:\n"); 
      for (i=0; i<argc; i++) 
      printf("[%2d] : %s\n", i, argv[i]); 

      printf("About to exec child with arg1 arg2 ...\n"); 
      execv("CHILD.EXE", argv); 

      perror("exec error"); 

      exit(1); 
      } 



      函数名: exit 
      功 能: 终止程序 
      用 法: void exit(int status); 
      程序例: 

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

      int main(void) 
      { 
      int status; 

      printf("Enter either 1 or 2\n"); 
      status = getch(); 
      /* Sets DOS errorlevel */ 
      exit(status - '0'); 

      /* Note: this line is never reached */ 
      return 0; 
      } 



      函数名: exp 
      功 能: 指数函数 
      用 法: double exp(double x); 
      程序例: 

      #include <stdio.h> 
      #include <math.h> 

      int main(void) 
      { 
      double result; 
      double x = 4.0; 

      result = exp(x); 
      printf("'e' raised to the power \ 
      of %lf (e ^ %lf) = %lf\n", 
      x, x, result); 

      return 0; 
      } 





最后进行编辑的是 蓝色键盘 on 2003-05-20 12:53, 总计第 1 次编辑

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     蓝色键盘      




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      代码:

      函数名: exp 
      功 能: 指数函数 
      用 法: double exp(double x); 
      程序例: 

      #include <stdio.h> 
      #include <math.h> 

      int main(void) 
      { 
      double result; 
      double x = 4.0; 

      result = exp(x); 
      printf("'e' raised to the power \ 
      of %lf (e ^ %lf) = %lf\n", 
      x, x, result); 

      return 0; 
      } 
      函数名: fabs 
      功 能: 返回浮点数的绝对值 
      用 法: double fabs(double x); 
      程序例: 
      #include <stdio.h> 
      #include <math.h> 

      int main(void) 
      { 
      float number = -1234.0; 

      printf("number: %f absolute value: %f\n", 
      number, fabs(number)); 
      return 0; 
      } 




      函数名: farcalloc 
      功 能: 从远堆栈中申请空间 
      用 法: void far *farcalloc(unsigned long units, unsigned ling 
      unitsz); 
      程序例: 
      #include <stdio.h> 
      #include <alloc.h> 
      #include <string.h> 
      #include <dos.h> 

      int main(void) 
      { 
      char far *fptr; 
      char *str = "Hello"; 

      /* allocate memory for the far pointer */ 
      fptr = farcalloc(10, sizeof(char)); 

      /* copy "Hello" into allocated memory */ 
      /* 
      Note: movedata is used because you 
      might be in a small data model, in 
      which case a normal string copy routine 
      can not be used since it assumes the 
      pointer size is near. 
      */ 
      movedata(FP_SEG(str), FP_OFF(str), 
      FP_SEG(fptr), FP_OFF(fptr), 
      strlen(str)); 

      /* display string (note the F modifier) */ 
      printf("Far string is: %Fs\n", fptr); 

      /* free the memory */ 
      farfree(fptr); 

      return 0; 
      } 




      函数名: farcoreleft 
      功 能: 返回远堆中未作用存储区大小 
      用 法: long farcoreleft(void); 
      程序例: 

      #include <stdio.h> 
      #include <alloc.h> 

      int main(void) 
      { 
      printf("The difference between the\ 
      highest allocated block in the\ 
      far\n"); 
      printf("heap and the top of the far heap\ 
      is: %lu bytes\n", farcoreleft()); 

      return 0; 
      } 




      函数名: farfree 
      功 能: 从远堆中释放一块 
      用 法: void farfree(void); 
      程序例: 

      #include <stdio.h> 
      #include <alloc.h> 
      #include <string.h> 
      #include <dos.h> 

      int main(void) 
      { 
      char far *fptr; 
      char *str = "Hello"; 

      /* allocate memory for the far pointer */ 
      fptr = farcalloc(10, sizeof(char)); 

      /* copy "Hello" into allocated memory */ 
      /* 
      Note: movedata is used because you might be in a small data 
      model, 
      in which case a normal string copy routine can't be used since 
      it 
      assumes the pointer size is near. 
      */ 
      movedata(FP_SEG(str), FP_OFF(str), 
      FP_SEG(fptr), FP_OFF(fptr), 
      strlen(str)); 

      /* display string (note the F modifier) */ 
      printf("Far string is: %Fs\n", fptr); 

      /* free the memory */ 
      farfree(fptr); 

      return 0; 
      } 




      函数名: farmalloc 
      功 能: 从远堆中分配存储块 
      用 法: void far *farmalloc(unsigned long size); 
      程序例: 

      #include <stdio.h> 
      #include <alloc.h> 
      #include <string.h> 
      #include <dos.h> 

      int main(void) 
      { 
      char far *fptr; 
      char *str = "Hello"; 

      /* allocate memory for the far pointer */ 
      fptr = farmalloc(10); 

      /* copy "Hello" into allocated memory */ 
      /* 
      Note: movedata is used because we might 
      be in a small data model, in which case 
      a normal string copy routine can not be 
      used since it assumes the pointer size 
      is near. 
      */ 
      movedata(FP_SEG(str), FP_OFF(str), 
      FP_SEG(fptr), FP_OFF(fptr), 
      strlen(str)); 

      /* display string (note the F modifier) */ 
      printf("Far string is: %Fs\n", fptr); 

      /* free the memory */ 
      farfree(fptr); 

      return 0; 
      } 




      函数名: farrealloc 
      功 能: 调整远堆中的分配块 
      用 法: void far *farrealloc(void far *block, unsigned long 
      newsize); 
      程序例: 

      #include <stdio.h> 
      #include <alloc.h> 

      int main(void) 
      { 
      char far *fptr; 

      fptr = farmalloc(10); 
      printf("First address: %Fp\n", fptr); 
      fptr = farrealloc(fptr,20); 
      printf("New address : %Fp\n", fptr); 
      farfree(fptr); 
      return 0; 
      } 



      函数名: fclose 
      功 能: 关闭一个流 
      用 法: int fclose(FILE *stream); 
      程序例: 

      #include <string.h> 
      #include <stdio.h> 

      int main(void) 
      { 
      FILE *fp; 
      char buf[11] = "0123456789"; 

      /* create a file containing 10 bytes */ 
      fp = fopen("DUMMY.FIL", "w"); 
      fwrite(&buf, strlen(buf), 1, fp); 

      /* close the file */ 
      fclose(fp); 
      return 0; 
      } 




      函数名: fcloseall 
      功 能: 关闭打开流 
      用 法: int fcloseall(void); 
      程序例: 

      #include <stdio.h> 

      int main(void) 
      { 
      int streams_closed; 

      /* open two streams */ 
      fopen("DUMMY.ONE", "w"); 
      fopen("DUMMY.TWO", "w"); 

      /* close the open streams */ 
      streams_closed = fcloseall(); 

      if (streams_closed == EOF) 
      /* issue an error message */ 
      perror("Error"); 
      else 
      /* print result of fcloseall() function */ 
      printf("%d streams were closed.\n", streams_closed); 

      return 0; 
      } 



      函数名: fcvt 
      功 能: 把一个浮点数转换为字符串 
      用 法: char *fcvt(double value, int ndigit, int *decpt, int 
      *sign); 
      程序例: 

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

      int main(void) 
      { 
      char *string; 
      double value; 
      int dec, sign; 
      int ndig = 10; 

      clrscr(); 
      value = 9.876; 
      string = ecvt(value, ndig, &dec, &sign); 
      printf("string = %s dec = %d \ 
      sign = %d\n", string, dec, sign); 

      value = -123.45; 
      ndig= 15; 
      string = ecvt(value,ndig,&dec,&sign); 
      printf("string = %s dec = %d sign = %d\n", 
      string, dec, sign); 


      value = 0.6789e5; /* scientific 
      notation */ 
      ndig = 5; 
      string = ecvt(value,ndig,&dec,&sign); 
      printf("string = %s dec = %d\ 
      sign = %d\n", string, dec, sign); 

      return 0; 
      } 




      函数名: fdopen 
      功 能: 把流与一个文件句柄相接 
      用 法: FILE *fdopen(int handle, char *type); 
      程序例: 

      #include <sys\stat.h> 
      #include <stdio.h> 
      #include <fcntl.h> 
      #include <io.h> 

      int main(void) 
      { 
      int handle; 
      FILE *stream; 

      /* open a file */ 
      handle = open("DUMMY.FIL", O_CREAT, 
      S_IREAD | S_IWRITE); 

      /* now turn the handle into a stream */ 
      stream = fdopen(handle, "w"); 

      if (stream == NULL) 
      printf("fdopen failed\n"); 
      else 
      { 
      fprintf(stream, "Hello world\n"); 
      fclose(stream); 
      } 
      return 0; 
      } 



      函数名: feof 
      功 能: 检测流上的文件结束符 
      用 法: int feof(FILE *stream); 
      程序例: 

      #include <stdio.h> 

      int main(void) 
      { 
      FILE *stream; 

      /* open a file for reading */ 
      stream = fopen("DUMMY.FIL", "r"); 

      /* read a character from the file */ 
      fgetc(stream); 

      /* check for EOF */ 
      if (feof(stream)) 
      printf("We have reached end-of-file\n"); 

      /* close the file */ 
      fclose(stream); 
      return 0; 
      } 



      函数名: ferror 
      功 能: 检测流上的错误 
      用 法: int ferror(FILE *stream); 
      程序例: 

      #include <stdio.h> 

      int main(void) 
      { 
      FILE *stream; 

      /* open a file for writing */ 
      stream = fopen("DUMMY.FIL", "w"); 

      /* force an error condition by attempting to read */ 
      (void) getc(stream); 

      if (ferror(stream)) /* test for an error on the stream */ 
      { 
      /* display an error message */ 
      printf("Error reading from DUMMY.FIL\n"); 

      /* reset the error and EOF indicators */ 
      clearerr(stream); 
      } 

      fclose(stream); 
      return 0; 
      } 




      函数名: fflush 
      功 能: 清除一个流 
      用 法: int fflush(FILE *stream); 
      程序例: 

      #include <string.h> 
      #include <stdio.h> 
      #include <conio.h> 
      #include <io.h> 

      void flush(FILE *stream); 

      int main(void) 
      { 
      FILE *stream; 
      char msg[] = "This is a test"; 

      /* create a file */ 
      stream = fopen("DUMMY.FIL", "w"); 

      /* write some data to the file */ 
      fwrite(msg, strlen(msg), 1, stream); 

      clrscr(); 
      printf("Press any key to flush\ 
      DUMMY.FIL:"); 
      getch(); 

      /* flush the data to DUMMY.FIL without\ 
      closing it */ 
      flush(stream); 

      printf("\nFile was flushed, Press any key\ 
      to quit:"); 
      getch(); 
      return 0; 
      } 

      void flush(FILE *stream) 
      { 
      int duphandle; 

      /* flush the stream's internal buffer */ 
      fflush(stream); 

      /* make a duplicate file handle */ 
      duphandle = dup(fileno(stream)); 

      /* close the duplicate handle to flush\ 
      the DOS buffer */ 
      close(duphandle); 
      } 




      函数名: fgetc 
      功 能: 从流中读取字符 
      用 法: int fgetc(FILE *stream); 
      程序例: 

      #include <string.h> 
      #include <stdio.h> 
      #include <conio.h> 

      int main(void) 
      { 
      FILE *stream; 
      char string[] = "This is a test"; 
      char ch; 

      /* open a file for update */ 
      stream = fopen("DUMMY.FIL", "w+"); 

      /* write a string into the file */ 
      fwrite(string, strlen(string), 1, stream); 

      /* seek to the beginning of the file */ 
      fseek(stream, 0, SEEK_SET); 

      do 
      { 
      /* read a char from the file */ 
      ch = fgetc(stream); 

      /* display the character */ 
      putch(ch); 
      } while (ch != EOF); 

      fclose(stream); 
      return 0; 
      } 




      函数名: fgetchar 
      功 能: 从流中读取字符 
      用 法: int fgetchar(void); 
      程序例: 

      #include <stdio.h> 

      int main(void) 
      { 
      char ch; 

      /* prompt