lseek(2) [hpux man page]

lseek(2)							System Calls Manual							  lseek(2)

NAME

       lseek - move read/write file pointer; seek

SYNOPSIS

DESCRIPTION

       sets the file pointer associated with the file descriptor as follows:

	      o  If whence is the pointer is set to offset bytes.

	      o  If whence is the pointer is set to its current location plus offset.

	      o  If whence is the pointer is set to the size of the file plus offset.

       These symbolic constants are defined in

RETURN VALUE

       When completes successfully, it returns an integer, which is the resulting file offset as measured in bytes from the beginning of the file.
       Otherwise, a value of is returned and is set to indicate the error.

       For all files that are not character or block special files, the integer returned on successful completion is non-negative.  For  character
       or  block  special  files that correspond to disk sections larger than 2 gigabytes, a non-negative integer is returned for successful seeks
       beyond 2 gigabytes.  This value is the resulting file offset as measured in bytes from the beginning of the file, when taken as an unsigned
       value.  always indicates an error return, even when encountered on greater than 2 gigabyte disk sections.  The call succeeds for NFS direc-
       tories even if the resulting file offset becomes negative.

ERRORS

       fails and the file offset remains unchanged if one or more of the following is true:

       [EBADF]	      fildes is not an open file descriptor.

       [ESPIPE]       fildes is associated with a pipe, socket, or FIFO.

       [EINVAL]       whence is not one of the supported values.

       [EINVAL]       The resulting file offset would be negative.

       [EINVAL]       The resulting file offset would be a value which cannot be represented correctly in an object of type

WARNINGS

       Some devices are incapable of seeking.  The value of the file offset associated with such a device is undefined.

       Using with a whence of on device special files is not supported and the results are not defined.

SEE ALSO

       creat(2), dup(2), fcntl(2), lseek64(2), open(2), unistd(5).

STANDARDS CONFORMANCE

																	  lseek(2)

Check Out this Related Man Page

lseek(2)							System Calls Manual							  lseek(2)

Name
       lseek, tell - move read or write pointer

Syntax
       #include <sys/types.h>
       #include <unistd.h>

       pos = lseek(d, offset, whence)
       off_t pos;
       int d, whence;
       off_t offset;

       pos = tell(d)
       off_t pos;
       int d;

Description
       The system call moves the file pointer associated with a file or device open for reading or writing.

       The descriptor d refers to a file or device open for reading or writing.  The system call sets the file pointer of d as follows:

       o    If whence is SEEK_SET, the pointer is set to offset bytes.

       o    If whence is SEEK_CUR the pointer is set to its current location plus offset.

       o    If whence is SEEK_END, the pointer is set to the size of the file plus offset.

       Seeking beyond the end of a file and then writing to the file creates a gap or hole that does not occupy physical space and reads as zeros.

       The system call returns the offset of the current byte relative to the beginning of the file associated with the file descriptor.

Environment
   System Five
       If  you	compile  a  program  in  the System Five environment, an invalid whence argument causes SIGSYS to be sent.  This complies with the
       behavior described in the System V Interface Definition (SVID), Issue 1.

Return Values
       Upon successful completion, a long integer (the current file pointer value) is returned.  This pointer is measured in bytes from the begin-
       ning  of  the file, where the first byte is byte 0.  (Note that some devices are incapable of seeking.  The value of the pointer associated
       with such a device is undefined.)  If a value of -1 is returned, errno is set to indicate the error.

Diagnostics
       The system call fails and the file pointer remains unchanged under the following conditions:

       [EBADF]	      The fildes is not an open file descriptor.

       [EINVAL]       The whence is not a proper value.

       [ESPIPE]       The fildes is associated with a pipe or a socket.

See Also
       dup(2), open(2)

																	  lseek(2)

Linux and UNIX Man Pages

lseek(2) [hpux man page]

Check Out this Related Man Page