SYNTAX

   C Syntax
          #include <mpi.h>

          int MPI_Info_get_string(MPI_Info info, const char *key, int *buflen, char *value, int *flag)

   Fortran Syntax
          USE MPI
          ! or the older form: INCLUDE 'mpif.h'
          MPI_INFO_GET_STRING(INFO, KEY, BUFLEN, VALUE, FLAG, IERROR)
               INTEGER INFO, BUFLEN, IERROR
               CHARACTER*(*) KEY, VALUE
               LOGICAL FLAG

   Fortran 2008 Syntax
          USE mpi_f08
          MPI_Info_get_string(info, key, buflen, value, flag, ierror)
               TYPE(MPI_Info), INTENT(IN) :: info
               CHARACTER(LEN=*), INTENT(IN) :: key
               INTEGER, INTENT(INOUT) :: buflen
               CHARACTER(LEN=valuelen), INTENT(OUT) :: value
               LOGICAL, INTENT(OUT) :: flag
               INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS

       • info: Info object (handle).

       • key: Key (string).

OUTPUT PARAMETER

       • buflen On entry, length of value arg. On return, set to required size to: hold value string (integer).

       • value: Value (string).

       • flag: Returns true if key defined, false if not (boolean).

       • ierror: Fortran only: Error status (integer).

DESCRIPTION

       MPI_Info_get_string  retrieves  the  value associated with key from info, if any. If such a key exists in
       info, it sets flag to true and returns the value in value, otherwise it sets flag  to  false  and  leaves
       value  unchanged.  buflen on input is the size of the provided buffer, for the output of buflen it is the
       size of the buffer needed to store the value string. If the buflen passed into the function is less  than
       the  actual  size  needed  to  store  the  value  string  (including  null terminator in C), the value is
       truncated. On return, the value of buflen will be set to the required  buffer  size  to  hold  the  value
       string.  If  buflen  is  set to 0, value is not changed. In C, buflen includes the required space for the
       null terminator. In C, this function returns a null terminated string in all cases where the buflen input
       value is greater than 0.

       If key is larger than MPI_MAX_INFO_KEY, the call is erroneous.

ERRORS

       Almost all MPI routines return an error value; C routines as  the  return  result  of  the  function  and
       Fortran routines in the last argument.

       Before  the  error  value  is  returned,  the current MPI error handler associated with the communication
       object (e.g., communicator, window, file) is called.  If no communication object is associated  with  the
       MPI  call,  then  the call is considered attached to MPI_COMM_SELF and will call the associated MPI error
       handler.  When  MPI_COMM_SELF  is  not  initialized   (i.e.,   before   MPI_Init/MPI_Init_thread,   after
       MPI_Finalize,  or  when using the Sessions Model exclusively) the error raises the initial error handler.
       The initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF  when  using
       the  World  model,  or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_Comm_spawn/‐
       MPI_Comm_spawn_multiple.  If no other appropriate error handler has been set, then the  MPI_ERRORS_RETURN
       error  handler  is  called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all
       other MPI functions.

       Open MPI includes three predefined error handlers that can be used:

       • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

       • MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When
         called on a communicator, it acts as if MPI_Abort was called on  that  communicator.  If  called  on  a
         window  or file, acts as if MPI_Abort was called on a communicator containing the group of processes in
         the corresponding window or file. If called on a session, aborts only the local process.

       • MPI_ERRORS_RETURN Returns an error code to the application.

       MPI applications can also implement their own error handlers by calling:

       • MPI_Comm_create_errhandler then MPI_Comm_set_errhandler

       • MPI_File_create_errhandler then MPI_File_set_errhandler

       • MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init

       • MPI_Win_create_errhandler then MPI_Win_set_errhandler

       Note that MPI does not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.

       See the Error Handling section of the MPI-3.1 standard for more information.

       SEE ALSO:

          • MPI_Info_create

          • MPI_Info_delete

          • MPI_Info_dup

          • MPI_Info_free

          • MPI_Info_get_nkeys

          • MPI_Info_get_nthkey

          • MPI_Info_set

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                            MPI_INFO_GET_STRING(3)