petsc-3.12.5 2020-03-29
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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
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 to file ALWAYS using big-endian ordering. On small-endian machines the numbers are converted to the small-endian format when they are read in from the file. When PETSc is ./configure with --with-64bit-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-64bit-indices is used.

See Also

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

Level

developer

Location

src/sys/fileio/sysio.c

Examples

src/vec/vec/examples/tutorials/ex6.c.html
src/vec/vec/examples/tutorials/ex6f.F90.html
src/dm/examples/tutorials/ex15.c.html
src/ksp/ksp/examples/tutorials/ex54f.F90.html

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Index of all manual pages