frewind

Move file position pointer to beginning of open file

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Syntax

frewind(fileID)

Description

frewind(fileID) sets the file position indicator to the beginning of a file.

example

Examples

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Open Live Script

Open the following file, perform a read operation, and then move the file position indicator back to the beginning of the file.

Use fopen to open the file, and then use fgetl to read the first two lines.

fid = fopen('badpoem.txt');
tline1 = fgetl(fid)  % read first line 
tline1 = 
'Oranges and lemons,'

tline2 = fgetl(fid)  % read second line
tline2 = 
'Pineapples and tea.'

The previous two read operations moved the position indicator to the beginning of line 3 in the poem. As a result, the next read operation using fgetl returns line 3. 

tline3 = fgetl(fid)
tline3 = 
'Orangutans and monkeys,'

To reread the first line of the file, reset the position indicator using the frewind function, and then perform the read operation.

frewind(fid)
fgetl(fid)
ans = 
'Oranges and lemons,'

Close the file.

fclose(fid);

Input Arguments

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File identifier of an open file, specified as an integer. Before using frewind, you must use fopen to open the file and obtain its identifier fileID.

Data Types: double

Tips

If the file is on a tape device and the rewind operation fails, frewind does not return an error message.

Alternatives

frewind(fileID) is equivalent to:

fseek(fileID, 0, 'bof');

Extended Capabilities

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C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced before R2006a

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See Also

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