BSD 4 release

[unix-history] / usr / src / libc / stdio / fopen.c

#include        <stdio.h>
#include        <errno.h>

FILE *
fopen(file, mode)
char *file;
register char *mode;
{
       extern int errno;
       register f;
       register FILE *iop;
       extern FILE *_lastbuf;

       for (iop = _iob; iop->_flag&(_IOREAD|_IOWRT); iop++)
               if (iop >= _lastbuf)
                       return(NULL);
       if (*mode=='w')
               f = creat(file, 0666);
       else if (*mode=='a') {
               if ((f = open(file, 1)) < 0) {
                       if (errno == ENOENT)
                               f = creat(file, 0666);
               }
               if (f >= 0)
                       lseek(f, 0L, 2);
       } else
               f = open(file, 0);
       if (f < 0)
               return(NULL);
       iop->_cnt = 0;
       iop->_file = f;
       if (*mode != 'r')
               iop->_flag |= _IOWRT;
       else
               iop->_flag |= _IOREAD;
       return(iop);
}