count = fwrite(fid, data)
count = fwrite(fid, data, precision)
count = fwrite(fid, data, precision, skip)
count = fwrite(fid, data, precision, skip, arch)
count = fwrite(fid, data, precision, arch)
[count, bytes] = fwrite(fid, ...)
| Parameter | Description |
|---|---|
| fid | a file descriptor |
| data | data to write |
| precision | class of values to read |
| skip | number of bytes to skip |
| arch | a string specifying the data format for the file. |
| Parameter | Description |
|---|---|
| count | -1 or number of elements written |
| bytes | number of bytes written |
Write data in binary form to the file specified by the file descriptor fid.
characters encoding uses fopen parameter.
supported architecture:
native , n: format of the current machine.
ieee-be, b: IEEE big endian.
ieee-le, l: IEEE little endian.
supported precision:
| Value Type | Precision | Bits (Bytes) |
|---|---|---|
| Logical | 'logical' | platform-dependent |
| Floating-point numbers | 'double', 'real*8', 'float64' | 64 (8) |
| 'single', 'real*4', 'float32' | 32 (4) | |
| Integers, signed | 'int' | 32 (4) |
| 'int8', 'integer*1', 'schar' | 8 (1) | |
| 'int16', 'integer*2' | 16 (2) | |
| 'int32', 'integer*4' | 32 (4) | |
| 'int64', 'integer*8' | 64 (8) | |
| Integers, unsigned | 'uint8', 'uchar' | 8 (1) |
| 'uint16' | 16 (2) | |
| 'uint32' | 32 (4) | |
| 'uint64' | 64 (8) | |
| Characters | 'char', '*char' | depends encoding with fopen. |
| 'char*1' | depends encoding with fopen. |
if fwrite fails, it returns a negative value.
iffwrite succeeds, it returns the number of elements written successfully.
iffwrite writes characters, it returns the number of characters written successfully and not the number of elements.
A = rand(3,1)
fileID = fopen([tempdir(), 'doubledata.bin'],'w');
fwrite(fileID, A,'double');
fclose(fileID);
fileID = fopen([tempdir(), 'doubledata.bin'],'r');
R = fread(fileID, 'double')
fclose(fileID);test_string = 'é ö ä ü è ê';
fid = fopen([tempdir(), 'fwrite_example_char.txt'], 'w','n', 'UTF-8');
[count, bytes] = fwrite(fid, test_string) % returns 11 and 17
fclose(fid);
% This is the number of characters written and not the number of bytes.
% Each accented character (é, ö, ä, ü, è, ê) = 2 bytes each
% Each space = 1 byte
% Total bytes = 6*2 + 5*1 = 17 bytes| Version | Description |
|---|---|
| 1.0.0 | initial version |
| 1.15.0 | fwrite returns the number of characters written for character data. |