functions in std.i - o
or f= open(filename, filemode)
or f= open(filename, filemode, errmode)
opens the file FILENAME according to FILEMODE (both are strings).
If ERRMODE is non-nil and non-zero, fail by returning nil F,
otherwise failure to open or create the file is a runtime error.
To use ERRMODE to check for the existence of a file:
if (open(filename,"r",1)) file_exists;
The return value F is an IOStream (or just stream for short). When
the last reference to this return value is discarded, the file will
be closed. The file can also be explicitly closed with the close
function. The FILEMODE determines whether the file is to be
opened in read, write, or update mode, and whether writes are
restricted to the end-of-file (append mode). FILEMODE also
determines whether the file is opened as a text file or as a
binary file. FILEMODE can have the following values, which are
the same as for the ANSI standard fopen function:
"r" - read only
"w" - write only, random access, existing file overwritten
"a" - write only, forced to end-of-file,
existing file preserved
"r+" - read/write, random access, existing file preserved
"w+" - read/write, random access, existing file overwritten
"a+" - read/write, reads random access,
writes forced to end-of-file, existing file preserved
"rb" "wb" "ab" "r+b" "rb+" "w+b" "wb+" "a+b" "ab+"
without b means text file, with b means binary file
The default FILEMODE is "r" -- open an existing text file for
The read and write functions perform I/O on text files.
I/O to binary files may be performed explicitly using the save
and restore functions, or implicitly by using the stream variable
F as if it were a data structure instance (e.g.- f.x refers to
variable x in the binary file f).
builtin function, documented at i0/std.i line 1282
or file= openb(filename, clogfile)
open the existing file FILENAME for read-only binary I/O.
(Use updateb or createb, respectively, to open an existing file
with read-write access or to create a new file.)
If the CLOGFILE argument is supplied, it represents the structure
of FILENAME in the Clog binary data description language.
After an openb, the file variable may be used to extract variables
from the file as if it were a structure instance. That is, the
expression "file.var" refers to the variable "var" in file "file".
A complete list of the variable names present in the file may
be obtained using the get_vars function. If the file contains
history records, the jt and jc functions may be used to set the
current record -- initially, the first record is current.
The restore function may be used to make memory copies of data
in the file; this will be faster than a large number of
references to "file.var".
interpreted function, defined at i0/std.i line 1791
list of functions to be tried by openb if the file to be
opened is not a PDB file. By default,
openb_hooks= _lst(_not_pdbf, _not_cdf).
The hook functions will be called with the file as argument
(e.g.- _not_cdf(file)), beginning with _car(openb_hooks), until
one of them returns 0. Note that a hook should return 0 if it
"recognizes" the file as one that it should be able to open, but
finds that the file is misformatted (alternatively, it could call
error to abort the whole process).
keyword, defined at i0/std.i line 2044
returns a vector of integers describing the dimensions of OBJECT.
The format of the vector is [number of dims, origin1, origin2, ...].
By default, dimension origins are ignored, but use_origins changes
this. The dimsof function returns the length of each dimension.
*** NOTE NOTE NOTE ***
Unless use_origins(1) is in effect, orgsof will always return
1 for all of the originI in the list. Thus, whether use_origins(1)
is in effect or not, you are guaranteed that x(orgsof(x)(2)) is the
first element of x.
builtin function, documented at i0/std.i line 348