memmapfile — Map file bytes into a MATLAB-compatible memmapfile object.
Maps file bytes into a MATLAB-compatible memmapfile object with typed Format, Offset, Repeat, Writable metadata, and Data fields.
Syntax
m = memmapfile(filename, Name, Value)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
input1 | Any | Yes | — | First input argument. |
input2 | Any | Yes | — | Second input argument. |
input3 | Any | No | — | Optional third input argument. |
Returns
| Name | Type | Description |
|---|---|---|
value | Any | Result value. |
How memmapfile works
- Supports all documented scalar integer Format type names (
int8,int16,int32,int64,uint8,uint16,uint32, anduint64) plussingleanddouble; integer bytes decode directly into matching native storage without floating coercion. - Supports MATLAB-style Format cells such as {type, shape, field}; named formats return Data as a struct field.
- Offset and Repeat are honored for typed reads. Offset beyond end of file is rejected. Typed-integer
Writable,Offset,Repeat, and Format-shape controls are exact RunMat extensions and reject in MATLAB-compatible modes because current public evidence specifies logical/double controls and does not establish typed-integer Format dimensions. - Automatic resident controls gather transparently through their owning provider. Explicit resident arguments reject in compatibility mode before provider access and are admitted only when RunMat extensions are enabled.
- The current implementation materializes mapped data into host memory; Writable is recorded but write-through mapping is not implemented yet.
Using memmapfile with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how memmapfile changes the result.
Run a small memmapfile example, explain the result, then change one input and compare the output.
Related Io functions
Repl Fs
addpath · cd · copyfile · delete · dir · exist · fileattrib · fileparts · fullfile · genpath · getenv · getpref · isenv · isfile · isfolder · ispref · ls · matlabroot · mkdir · movefile · open · opentoline · path · pathsep · pcode · pwd · readstruct · rehash · restoredefaultpath · rmdir · rmpath · run · savepath · setenv · setpref · system · tempdir · tempname · uigetdir · uigetfile · uiputfile · unsetenv · userpath · what · winqueryreg · xmlread · xmlwrite
Tabular
arrayDatastore · csvread · csvwrite · detectImportOptions · dlmread · dlmwrite · fileDatastore · parquetDatastore · parquetinfo · parquetread · readcell · readmatrix · readtable · readtimetable · spreadsheetImportOptions · writecell · writematrix · writetable · writetimetable · xlsread · xlswrite
Filetext
fclose · feof · fgetl · fgets · fileread · filewrite · fopen · fprintf · fread · frewind · fwrite · readlines · writelines
Import
Json
About RunMat
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