llseek(2) [sunos man page]
llseek(2) System Calls llseek(2) NAME
llseek - move extended read/write file pointer SYNOPSIS
#include <sys/types.h> #include <unistd.h> offset_t llseek(int fildes, offset_t offset, int whence); DESCRIPTION
The llseek() function sets the 64-bit extended file pointer associated with the open file descriptor specified by fildes 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. Although each file has a 64-bit file pointer associated with it, some existing file system types (such as tmpfs) do not support the full range of 64-bit offsets. In particular, on such file systems, non-device files remain limited to offsets of less than two gigabytes. Device drivers may support offsets of up to 1024 gigabytes for device special files. Some devices are incapable of seeking. The value of the file pointer associated with such a device is undefined. RETURN VALUES
Upon successful completion, llseek() returns the resulting pointer location as measured in bytes from the beginning of the file. Remote file descriptors are the only ones that allow negative file pointers. Otherwise, -1 is returned, the file pointer remains unchanged, and errno is set to indicate the error. ERRORS
The llseek() function will fail if: EBADF The fildes argument is not an open file descriptor. EINVAL The whence argument is not SEEK_SET, SEEK_CUR, or SEEK_END; the offset argument is not a valid offset for this file system type; or the fildes argument is not a remote file descriptor and the resulting file pointer would be negative. ESPIPE The fildes argument is associated with a pipe or FIFO. SEE ALSO
creat(2), dup(2), fcntl(2), lseek(2), open(2) SunOS 5.10 6 Jan 1999 llseek(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)