truncate(3C)         COMPATIBILITY FUNCTIONS         truncate(3C)



NAME
     truncate, ftruncate - set a file to a specified length

SYNOPSIS
     #include <unistd.h>

     int truncate (const char *path, offt length);

     int ftruncate (int fildes, offt length);

DESCRIPTION
     The file whose name is given by path or  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 effective user ID of the process must
     have write permission for the file, and  for  ftruncate  the
     file  must  be  open  for writing.  truncate fails if one or
     more of the following are true:

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

     EACCES            Write permission is denied  for  the  file
                       referred to by path.

     EFAULT            path points outside  the  process's  allo-
                       cated address space.

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

     EINVAL            path is not an ordinary file.

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

     EISDIR            The file referred to by path is  a  direc-
                       tory.

     ELOOP             Too many symbolic links  were  encountered
                       in translating path.

     EMFILE            The maximum  number  of  file  descriptors
                       available to the process has been reached.

     EMULTIHOP         Components of path require hopping to mul-
                       tiple remote machines and file system type
                       does not allow it.

     ENAMETOOLONG      The length of  a  path  component  exceeds



          Last change: C Programming Language Utilities         1

truncate(3C)         COMPATIBILITY FUNCTIONS         truncate(3C)



                       {NAME_MAX}  characters,  or  the length of
                       path exceeds {PATH_MAX} characters.

     ENFILE            Could not allocate any more space for  the
                       system file table.

     ENOENT            Either a component of the path  prefix  or
                       the  file  referred  to  by  path does not
                       exist.

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                       link to that machine is no longer active.

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

     EROFS             The file referred to by path resides on  a
                       read-only file system.

     ETXTBSY           The file referred to by  path  is  a  pure
                       procedure (shared text) file that is being
                       executed.  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.

SEE ALSO
     fcntl(2), open(2)

DIAGNOSTICS
     Upon successful completion, a value of 0 is returned.   Oth-
     erwise,  a value of -1 is returned and errno is set to indi-
     cate the error.





          Last change: C Programming Language Utilities         2