#include <db.h>

int
db_env_set_func_ftruncate(int (*func_ftruncate)(int fd, off_t offset));

The Berkeley DB library requires the ability to truncate a file.

The db_env_set_func_ftruncate method 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_ftruncate method 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_ftruncate method returns a non-zero error value on failure and 0 on success.

• The func_ftruncate parameter is the function which truncates a file.

  The fd parameter is an open file descriptor on the file.

  The ftruncate function must truncate the file to the byte length specified by the offset parameter.

  The func_ftruncate function must return the value of errno on failure and 0 on success.