truncate(3p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

TRUNCATE(3P)            POSIX Programmer's Manual           TRUNCATE(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

NAME         top

       truncate — truncate a file to a specified length

SYNOPSIS         top

       #include <unistd.h>

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

DESCRIPTION         top

       The truncate() function shall cause the regular file named by
       path to have a size which shall be equal to length bytes.

       If the file previously was larger than length, the extra data is
       discarded. If the file was previously shorter than length, its
       size is increased, and the extended area appears as if it were
       zero-filled.

       The application shall ensure that the process has write
       permission for the file.

       If the request would cause the file size to exceed the soft file
       size limit for the process, the request shall fail and the
       implementation shall generate the SIGXFSZ signal for the process.

       The truncate() function shall not modify the file offset for any
       open file descriptions associated with the file. Upon successful
       completion, truncate() shall mark for update the last data
       modification and last file status change timestamps of the file,
       and the S_ISUID and S_ISGID bits of the file mode may be cleared.

RETURN VALUE         top

       Upon successful completion, truncate() shall return 0. Otherwise,
       -1 shall be returned, and errno set to indicate the error.

ERRORS         top

       The truncate() function shall fail if:

       EINTR  A signal was caught during execution.

       EINVAL The length argument was less than 0.

       EFBIG or EINVAL
              The length argument was greater than the maximum file
              size.

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

       EACCES A component of the path prefix denies search permission,
              or write permission is denied on the file.

       EISDIR The named file is a directory.

       ELOOP  A loop exists in symbolic links encountered during
              resolution of the path argument.

       ENAMETOOLONG
              The length of a component of a pathname is longer than
              {NAME_MAX}.

       ENOENT A component of path does not name an existing file or path
              is an empty string.

       ENOTDIR
              A component of the path prefix names an existing file that
              is neither a directory nor a symbolic link to a directory,
              or the path argument contains at least one non-<slash>
              character and ends with one or more trailing <slash>
              characters and the last pathname component names an
              existing file that is neither a directory nor a symbolic
              link to a directory.

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

       The truncate() function may fail if:

       ELOOP  More than {SYMLOOP_MAX} symbolic links were encountered
              during resolution of the path argument.

       ENAMETOOLONG
              The length of a pathname exceeds {PATH_MAX}, or pathname
              resolution of a symbolic link produced an intermediate
              result with a length that exceeds {PATH_MAX}.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       open(3p)

       The Base Definitions volume of POSIX.1‐2017, unistd.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any
       discrepancy between this version and the original IEEE and The
       Open Group Standard, the original IEEE and The Open Group
       Standard is the referee document. The original Standard can be
       obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017                      TRUNCATE(3P)

Pages that refer to this page: unistd.h(0p)ftruncate(3p)