The name of the file to be preconnected is determined first by searching for an environment variable of the form FORTnn where nn is the two-digit logical unit number; e.g. FORT03. If this environment variable is found its value is used as the filename; otherwise the name "fort.n" is used; e.g. "fort.3". The file is opened either with FORM='FORMATTED' or FORM='UNFORMATTED' depending on whether the initial reference is with a formatted or unformatted i/o statement.
The BLANK and POSITION arguments control the BLANK= and POSITION= keywords in the implied OPEN statement when the file is preconnected; initially these are set to BLANK='NULL' and POSITION='REWIND'. Note that these have no meaning (and no effect) for unformatted files.
The PREFIX argument changes the prefix used to find the environment variable containing the preconnected file name. Initially this is "FORT". Only the first 30 characters of PREFIX are used.
The VERBOSE argument controls activity reporting; if it is .TRUE., subsequent preconnection activity will produce informative messages on the standard error unit.
© The Numerical Algorithms Group Ltd, Oxford UK. 2001