# MPI library
**MPI (Message Passing Interface)** is a library that enables you to write parallel programs in C or Fortran77. The library uses commonly available operating system services to create parallel processes and exchange information among these processes.

# MPI_Initialized

This function indicates if the `MPI_Init` method was called in a program.

# Syntax

```C
int MPI_Initialized(int *flag)
```

# Parameters

* **`flag`** acts as an output parameter that returns `true` if the `MPI_Init` or `MPI_Init_thread` is called, and `false` otherwise.

# Return value

The function returns an error if it is unsuccessful. By default, the error aborts the MPI job.

In case of success, it returns **`MPI_SUCCESS`**, the value returned upon successful termination of any MPI routine.


What is MPI_Initialized?

Indicates if MPI_Init was called, involving parallel programs in C/Fortran77, returns MPI_SUCCESS on success.