PetscBinaryWrite#

Writes to a binary file.

Synopsis#

PetscErrorCode PetscBinaryWrite(int fd, const void *p, PetscInt n, PetscDataType type)


Not Collective

Input Parameters#

• fd - the file

• p - the buffer

• n - the number of items to write

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

Notes#

PetscBinaryWrite() uses byte swapping to work on all machines; the files are written using big-endian ordering to the file. On little-endian machines the numbers are converted to the big-endian format when they are written to disk. 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.

If running with __float128 precision the output is in __float128 unless one uses the -binary_write_double option

The Buffer p should be read-write buffer, and not static data. This way, byte-swapping is done in-place, and then the buffer is written to the file.

This routine restores the original contents of the buffer, after it is written to the file. This is done by byte-swapping in-place the second time.

Because byte-swapping may be done on the values in data it cannot be declared const

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