11-08-2010
Well, arrays seem to be inside languages, where you just reach out and touch them.
Perhaps you are asking about mmap()/mmap64(), which turn the file into a memory array so you never need to seek (and flush and reload buffers) ever again and you get the use of as much RAM as you can scrounge to hold most recently used pages, even if not currently mapped? JAVA has a similar facility, FileChannel. I suppose PERL can do this, perhpas calling mmap()/mmap64() directly. Solaris reads with mmap*() and it also is used in dynamic linking, so all users of a lib file have the same memory pages. If 40 people are running vi, why have 40 different copies in different VM/RAM locations?
Head and tail with character -c arguments do seek and read in the shell.
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LEARN ABOUT OPENSOLARIS
tell
tell(3C) Standard C Library Functions tell(3C)
NAME
tell - return a file offset for a file descriptor
SYNOPSIS
#include <unistd.h>
off_t tell(int fd);
DESCRIPTION
The tell() function obtains the current value of the file-position indicator for the file descriptor fd.
RETURN VALUES
Upon successful completion, tell() returns the current value of the file-position indicator for fd measured in bytes from the beginning of
the file.
Otherwise, it returns -1 and sets errno to indicate the error.
ERRORS
The tell() function will fail if:
EBADF The file descriptor fd is not an open file descriptor.
EOVERFLOW The current file offset cannot be represented correctly in an object of type off_t.
ESPIPE The file descriptor fd is associated with a pipe or FIFO.
USAGE
The tell() function is equivalent to lseek(fd, 0, SEEK_CUR).
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
SEE ALSO
lseek(2), attributes(5)
SunOS 5.11 28 Jan 1998 tell(3C)