PetscBinaryRead#

Reads from a binary file.

Synopsis#

PetscErrorCode PetscBinaryRead(int fd, void *data, PetscInt num, PetscInt *count, PetscDataType type)

Not Collective

Input Parameters#

  • fd - the file descriptor

  • num - the maximum number of items to read

  • type - the type of items to read (PETSC_INT, PETSC_REAL, PETSC_SCALAR, etc.)

Output Parameters#

  • data - the buffer, this is an array of the type that matches the value in type

  • count - the number of items read, optional

Notes#

If count is not provided and the number of items read is less than the maximum number of items to read, then this routine errors.

PetscBinaryRead() uses byte swapping to work on all machines; the files are written ALWAYS using big-endian ordering. On little-endian machines the numbers are converted to the little-endian format when they are read in from the file. When PETSc is ./configure with --with-64-bit-indices the integers are written to the file as 64-bit integers, this means they can only be read back in when the option --with-64-bit-indices is used.

See Also#

PetscBinaryWrite(), PetscBinaryOpen(), PetscBinaryClose(), PetscViewerBinaryGetDescriptor(), PetscBinarySynchronizedWrite(), PetscBinarySynchronizedRead(), PetscBinarySynchronizedSeek()

Level#

developer

Location#

src/sys/fileio/sysio.c

Examples#

src/vec/vec/tutorials/ex6.c
src/dm/tutorials/ex15.c
src/vec/vec/tutorials/ex6f.F90


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