fwrite

Write data to a binary file

Syntax

y = fwrite ( file_id,x,precision )
y = file_id.fwrite ( x,precision )

Inputs

Outputs / Return Value

• y: y is the number of characters written. If an error occurs, y is null.

Notes

• This function reads a binary file and returns the data read according to file_id specified below.
• x is one of the following: "int8" "uint8" "int16" "uint16" "int32" "uint32" "int64" "uint64" "float" and "double"
• If file_id is audio, the data is scaled before writing to file according to x (e.g., for "int16" the maximum corresponds to 32767).
• If file_id is audio and stereo, the left and right channels are interleaved into the file.

Examples

An audio object of full-scale square wave with alternating 10 positive and 10 negative values written to file as int16
<p style="padding-left: 30px;">x = ones(10)++-ones(10)++ones(10)++-ones(10) // a non-audio vector
x = ...audio // x is now audio
fd=fopen("x.raw","wb")
fd.fwrite(x,"int16") // values of x in the range [-1 1] written to file after scaling with a 16-bit signed integer format (-32768 to 32767)
fd.fclose</p>

Similar signal as above but a non-audio object
<p style="padding-left: 30px;">y = 32767*ones(10)++-32768*ones(10)++32767*ones(10)++-32768*ones(10) // a non-audio vector
fd=fopen("y.raw","wb")
fd.fwrite(y,"int16") // values of y from -32768 to 32767 are written to file as is with a 16-bit signed integer format
fd.fclose</p>

The same files are generated in the above two examples (i.e., the raw file does not have any information about the data type of the object the file was created from).

See Also

• fopen
• fclose
• fread

Review Status

• Legacy parameter naming does not exactly match current engine metadata and should be reviewed manually.