writb fortran file binary write

## Syntax

    writb(file-name,a [,rec])

## Arguments

file-name

  string or integer

rec

  vector of positive integers. the selected records for direct access. This vector size must be equal to the number of rows of `a`

## Description

writes in binary format the matrix `a` in the file `'filename'`.. Matrix entries are stored on 4 byte words

For direct record access, file must have been previously opened using `file` function to set the record_length. `file-name` must be the result of the `file` function.

## See also

- file
- readb
- write
- mput
- write4b