WRITE(2)            Linux Programmer's Manual            WRITE(2)



NAME

       write - write to a file descriptor


SYNOPSIS

       #include <unistd.h>

       ssize_t write(int fd, const void *buf, size_t count);


DESCRIPTION

       write  writes  up to count bytes to the file referenced by
       the file descriptor fd from the buffer  starting  at  buf.
       POSIX  requires that a read() which can be proved to occur
       after a write() has returned returns the new  data.   Note
       that not all file systems are POSIX conforming.


RETURN VALUE

       On success, the number of bytes written are returned (zero
       indicates nothing was written).  On error, -1 is returned,
       and  errno is set appropriately.  If count is zero and the
       file descriptor refers  to  a  regular  file,  0  will  be
       returned  without causing any other effect.  For a special
       file, the results are not portable.


ERRORS

       EBADF  fd is not a valid file descriptor or  is  not  open
              for writing.

       EINVAL fd is attached to an object which is unsuitable for
              writing.

       EFAULT buf is outside your accessible address space.

       EPIPE  fd is connected to a pipe or socket  whose  reading
              end  is closed.  When this happens the writing pro-
              cess will receive a SIGPIPE signal; if it  catches,
              blocks or ignores this the error EPIPE is returned.

       EAGAIN Non-blocking I/O has been selected using O_NONBLOCK
              and the write would block.

       EINTR  The  call  was  interrupted  by a signal before any
              data was written.

       ENOSPC The device containing the file referred  to  by  fd
              has no room for the data.

       EIO    A  low-level I/O error occurred while modifying the
              inode.

       Other errors may occur, depending on the object  connected
       to fd.


CONFORMING TO

       SVr4,   SVID,   POSIX,  X/OPEN,  4.3BSD.   SVr4  documents



Linux 2.0.32             13 January 1996                        1





WRITE(2)            Linux Programmer's Manual            WRITE(2)


       additional  error  conditions  EDEADLK,   EFBIG,   ENOLCK,
       ENOLNK,  ENOSR,  ENXIO,  EPIPE,  or  ERANGE.  Under SVr4 a
       write may be interrupted and return EINTR  at  any  point,
       not just before any data is written.


SEE ALSO

       open(2), read(2), fcntl(2), close(2), lseek(2), select(2),
       ioctl(2), fsync(2), fwrite(3)

















































Linux 2.0.32             13 January 1996                        2