#include <db.h>

int
db_env_set_func_pread(ssize_t (*func_pread)(int fd, void *buf, 
    size_t nbytes, off_t offset));  

Replace Berkeley DB calls to the IEEE/ANSI Std 1003.1 (POSIX) pread function with func_pread, which must conform to the standard interface specification.

The db_env_set_func_pread() configures all operations performed by a process and all of its threads of control, not operations confined to a single database environment.

Although the db_env_set_func_pread() may be called at any time during the life of the application, it should normally be called before making calls to the db_env_create or db_create methods.

The db_env_set_func_pread() function returns a non-zero error value on failure and 0 on success.