petsc-3.14.6 2021-03-30

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_DOUBLE 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

Level

advanced

Location

src/sys/fileio/sysio.c

Examples

src/vec/vec/tutorials/ex6.c.html
src/vec/vec/tutorials/ex6f.F90.html

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Index of all manual pages