6.7.36SHOW ATOMIC

#Syntax

#Description

Show (i.e. get) the atomicity for accessing HDF5 files in an MPI environment. If using an HDFql non MPI-based distribution, an error is raised. If the keyword USE FILE is not specified, the atomicity refers to the default value for accessing (subsequent) files. Otherwise, if the keyword USE FILE is specified, the atomicity of the file currently in use is returned.

#Parameter(s)

post_processing_option – optional option that transforms the result set according to the programmer’s needs, such as ordering or truncating (please refer to the section PROCESSING for additional information).

output_redirecting_option – optional option that specifies the cursor in use, an HDF5 object (i.e. dataset or attribute), a (text, binary, or Excel) file, or memory (i.e. user-defined variable) to write the result set into (please refer to the subsection INTO for additional information). If not specified, the cursor in use is populated with the result set instead (please refer to the chapter CURSOR for additional information).

#Return

If the keyword BY NAME is not specified, it returns the status of the atomicity for accessing HDF5 files as an HDFQL_INT, which can either be HDFQL_ENABLED or HDFQL_DISABLED depending on whether the atomicity for accessing files is enabled or disabled, respectively. Otherwise, if the keyword BY NAME is specified, it returns the atomicity for accessing files as an HDFQL_VARCHAR, which can either be “ENABLED” or “DISABLED”.

#Example(s)

# enable atomicity for accessing HDF5 files in an MPI environment 
SET ATOMIC ENABLE

# show (i.e. get) atomicity for accessing HDF5 files in an MPI environment (should return 0 (i.e. HDFQL_ENABLED))
SHOW ATOMIC 

# use (i.e. open) an HDF5 file named "my_file0.h5" in parallel with atomicity when accessing it
USE FILE my_file0.h5 IN PARALLEL

# show (i.e. get) atomicity of the HDF5 file currently in use in an MPI environment (should return 0 (i.e. HDFQL_ENABLED))
SHOW USE FILE ATOMIC 

# disable atomicity for accessing HDF5 files in an MPI environment 
SET ATOMIC DISABLE

# show (i.e. get) atomicity for accessing HDF5 files in an MPI environment (should return -1 (i.e. HDFQL_DISABLED))
SHOW ATOMIC 

# use (i.e. open) an HDF5 file named "my_file1.h5" in parallel without atomicity when accessing it
USE FILE my_file1.h5 IN PARALLEL

# show (i.e. get) atomicity of the HDF5 file currently in use in an MPI environment (should return -1 (i.e. HDFQL_DISABLED))
SHOW USE FILE ATOMIC 

# use (i.e. open) an HDF5 file named "my_file2.h5" in parallel with atomicity when accessing it
USE FILE my_file2.h5 IN ATOMIC PARALLEL

# show (i.e. get) atomicity of the HDF5 file currently in use in an MPI environment (should return 0 (i.e. HDFQL_ENABLED))
SHOW USE FILE ATOMIC