NAME

     truncate, ftruncate - truncate a file to a specified length

SYNOPSIS

     #include <unistd.h>

     int truncate(const char *path, size_t length));
     int ftruncate(int fd, size_t length));

DESCRIPTION

     Truncate causes the file named by path or referenced  by  fd
     to  be  truncated  to  at most length bytes in size.  If the
     file previously was larger than this size, the extra data is
     lost.  With ftruncate, the file must be open for writing.

RETURN VALUE

     On success, zero is returned.  On error, -1 is returned, and
     errno is set appropriately.

ERRORS

     For truncate:

     ENOTDIR A component of the path prefix is not a directory.

     EINVAL  The pathname contains a  character  with  the  high-
             order bit set.

     ENAMETOOLONG
             A component of a pathname exceeded  255  characters,
             or an entire path name exceeded 1023 characters.

     ENOENT  The named file does not exist.

     EACCES  Search permission is denied for a component  of  the
             path prefix.

     EACCES  The named file is not writable by the user.

     ELOOP   Too  many  symbolic  links   were   encountered   in
             translating the pathname.

     EISDIR  The named file is a directory.

     EROFS   The named file resides on a read-only file system.

     ETXTBSY The file is a pure procedure (shared text) file that
             is being executed.

     EIO     An I/O error occurred updating the inode.

     EFAULT  Path points outside the process's allocated  address
             space.

     For Ftruncate:

     EBADF   The fd is not a valid descriptor.

     EINVAL  The fd references a socket, not a file.

     EINVAL  The fd is not open for writing.

CONFORMING TO

     4.4BSD, SVr4 (these function calls  first  appeared  in  BSD
     4.2).   SVr4  documents additional truncate error conditions
     EINTR,  EMFILE,  EMULTIHP,  ENAMETOOLONG,  ENFILE,  ENOLINK,
     ENOTDIR.   SVr4  ftruncate  documents  additional EAGAIN and
     EINTR error conditions.

BUGS

     These calls should be generalized to allow ranges  of  bytes
     in a file to be discarded.

SEE ALSO

     open(2)