myopen.c

运行在linux下的聊天软件

/*
  myopen.c
  
  For Free Chat
  
  By Bill Kendrick
  [e-mail]
  http://zippy.sonoma.edu/kendrick/
  
  October 1, 1996 - June 7, 1998
*/


#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include "myopen.h"
#include "defines.h"


/* Old myopen which used file locking when opening the file: */

FILE * myopen(char * file, char * mode)
{
  int modeint, fdi;
  FILE * fi;
  
  if (strcmp(mode, "r") == 0)
    modeint = O_RDONLY;
  else if (strcmp(mode, "w") == 0)
    modeint = O_CREAT | O_WRONLY | O_TRUNC;
  else if (strcmp(mode, "a") == 0)
    modeint = O_CREAT | O_WRONLY | O_APPEND;
  else
    return(NULL);
  
  fdi = open(file, modeint);
  
  if (fdi == -1)
    {
      printf("FDI returned -1!");
      return(NULL);
    }
  
#ifdef SYSV
  lockf(fdi, F_LOCK, 0);
#else
  flock(fdi, LOCK_EX);
#endif
  
  fi = fdopen(fdi, mode);
  
  return(fi);
}