5.6. File I/O at a Specified Offset: pread() and pwrite()

The pread() and pwrite() system calls operate just like read() and write(), except that the file I/O is performed at the location specified by offset, rather than at the current file offset. The file offset is left unchanged by these calls.

#include <unistd.h>

ssize_t pread(int fd, void *buf, size_t count, off_t offset);