Parallel I/O

The following classes are all defined within namespace HIPP::MPI.

Class File: the Parallel I/O Handler

class File

enum [anonymous] : int

enumerator sSET = MPI_SEEK_SET

enumerator sCUR = MPI_SEEK_CUR

enumerator sEND = MPI_SEEK_END

The seek specifications.

Memory management methods:

Method	Detail
default constructor	Not available.
copy constructor and operator=(&&)	Available; noexcept; shallow copy.
move constructor and operator=(const &)	Available; noexcept.

File(const Comm &comm, const string &name, const string &amode, const Info &info = Info::nullval())

Create a new file or open an existing file.

Parameters

• comm – The communicator, consisting of the processes involved in I/O.

• name – File name.

• amode – Visiting mode. Could be "r", "w", "wr", "c" ("create"), "excl", "delete_on_close", "unique_open", "sequential", "a" ("append"), or their comma-separated combination, e.g., "wr,c".

• info – Hints to the implementation.

ostream &info(ostream &os = cout, int fmt_cntl = 1) const

friend ostream &operator<<(ostream &os, const File &file)

info() displays some basic information of the file instance to os.

Parameters

fmt_cntl – Control the display format. 0 for inline information and 1 for a verbose, multiple-line information.

Returns

The argument os is returned.

The overloaded << operator is equivalent to info() with default fmt_cntl.

The returned reference of os allows you to chain the outputs, such as file.info(cout) << " continue printing " << endl.

void close() noexcept

Close the file. This can be called on any object (even a null value) or even multiple times.

static void del(const string &name, const Info &info = Info::nullval())

Delete a file named name.

bool is_null() const

static File nullval() noexcept

is_null() tests whether the instance is a null value.

nullval() returns a null value (internally MPI_FILE_NULL).

Group get_group() const

string get_amode() const

Querying file parameters.

get_group() returns a duplication of the group of the communicator used to open the file.

get_amode() returns the access mode associated with the file.

File &set_info(const Info &info)

Info get_info() const

File info management methods.

set_info() sets new values for the hints. It is a collective call. The info object may be different on each process, except if the implementation requires. Implementation may ignore the hints in this call because some info items cannot be changed after the creation or opening of the file.

get_info() returns the info containing all hints that is actually used by the system related to this file.

File &set_view(offset_t disp, const Datatype &etype, const Datatype &filetype, const string &datarep = "native", const Info &info = Info::nullval())

void get_view(offset_t &disp, Datatype &etype, Datatype &filetype, string &datarep) const

File views management methods.

set_view() changes that process’s view of the data in the file. The start of the view is disp (in bytes), the data type is etype and the distribution of data is sete by filetype, and the representation is set to datarep. set_view() also set the indivisual and shared file pointers to zero. This call is collective; datarep and the extents of etype must be identical on all processes in the group; disp, filetype, info may vary. The etype and filetype must be committed. User should ensure that all nonblocking calls and split collective calls have been complete - otherwise the call is erroneous.

get_view returns the process’s view of the data in the file.

template<typename ...Args>
Status read_at(offset_t offset, Args&&... args)

template<typename ...Args>
Status read_at_all(offset_t offset, Args&&... args)

template<typename ...Args>
Status write_at(offset_t offset, Args&&... args)

template<typename ...Args>
Status write_at_all(offset_t offset, Args&&... args)

template<typename ...Args>
Requests iread_at(offset_t offset, Args&&... args)

template<typename ...Args>
Requests iwrite_at(offset_t offset, Args&&... args)

template<typename ...Args>
void read_at_all_begin(offset_t offset, Args&&... args)

Status read_at_all_end(void *buf)

template<typename ...Args>
void write_at_all_begin(offset_t offset, Args&&... args)

Status write_at_all_end(const void *buf)

void seek(offset_t offset, int whence)

void seek(offset_t offset, const string &whence)

offset_t get_position() const

offset_t get_byte_offset(offset_t offset) const

template<typename ...Args>
Status read(Args&&... args)

template<typename ...Args>
Status read_all(Args&&... args)

template<typename ...Args>
Status write(Args&&... args)

template<typename ...Args>
Status write_all(Args&&... args)

template<typename ...Args>
Requests iread(Args&&... args)

template<typename ...Args>
Requests iwrite(Args&&... args)

template<typename ...Args>
void read_all_begin(Args&&... args)

Status read_all_end(void *buf)

template<typename ...Args>
void write_all_begin(Args&&... args)

Status write_all_end(const void *buf);

void seek_shared(offset_t offset, int whence)

void seek_shared(offset_t offset, const string &whence)

offset_t get_position_shared() const

template<typename ...Args>
Status read_shared(Args&&... args)

template<typename ...Args>
Status read_ordered(Args&&... args)

template<typename ...Args>
Status write_shared(Args&&... args)

template<typename ...Args>
Status write_ordered(Args&&... args)

template<typename ...Args>
Requests iread_shared(Args&&... args)

template<typename ...Args>
Requests iwrite_shared(Args&&... args)

template<typename ...Args>
void read_ordered_begin(Args&&... args)

Status read_ordered_end(void *buf)

template<typename ...Args>
void write_ordered_begin(Args&&... args)

Status write_ordered_end(const void *buf);

Data access calls. Please refer to MPI Standard for their usage.