ftruncate(3C)                  DG/UX 5.4R3.00                  ftruncate(3C)


NAME
       ftruncate - set a file to a specified length

SYNOPSIS
       #include <unistd.h>

       int ftruncate (int fildes, offt length);

DESCRIPTION
       The file whose name is referenced by the descriptor fildes has its
       size set to length bytes.

       If the file was previously longer than length, bytes past length will
       no longer be accessible.  If it was shorter, bytes from the EOF
       before the call to the EOF after the call will be read in as zeros.
       The file descriptor filedes must have been previously opened for
       writing.

       ftruncate fails if one or more of the following are true:

       EAGAIN            The file exists, mandatory file/record locking is
                         set, and there are outstanding record locks on the
                         file [see chmod(2)].

       EBADF             fildes is not a file descriptor open for writing.

       EINTR             A signal was caught during execution of the
                         ftruncate routine.

       EIO               An I/O error occurred while reading from or writing
                         to the file system.

       ENOLINK           fildes points to a remote machine and the link to
                         that machine is no longer active.

       EINVAL            fildes does not correspond to an ordinary file.

   Considerations for Threads Programming
                     +----------+-----------------------------+
                     |          |                      async- |
                     |function  | reentrant   cancel   cancel |
                     |          |              point    safe  |
                     +----------+-----------------------------+
                     |ftruncate |     Y          Y        N   |
                     +----------+-----------------------------+
SEE ALSO
       fcntl(2), open(2), truncate(2), reentrant(3).

DIAGNOSTICS
       Upon successful completion, a value of 0 is returned.  Otherwise, a
       value of -1 is returned and errno is set to indicate the error.






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