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ferror

File I/O error information

Syntax

message = ferror(fileID)
[message,errnum] = ferror(fileID)
[message,errnum] = ferror(fileID,'clear')

Description

message = ferror(fileID) returns the error message for the most recent file I/O operation on the specified file.

[message,errnum] = ferror(fileID) returns the error number that is associated with the error message.

[message,errnum] = ferror(fileID,'clear') clears the error indicator for the specified file. Specify the literal clear as a character vector or a string scalar. When you clear the error indicator, succeeding calls to ferror behave as if the most recent I/O operation is successful.

Input Arguments

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File identifier of an open file, specified as an integer. fileID can be one of these values:

  • N — Input or output from a file with a valid file identifier generated by the fopen function. N is equal to or greater than 3.

  • 0 — Input from a standard input device.

  • 1 — Output to a standard output device.

  • 2 — Standard error.

Data Types: double

Output Arguments

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Error message, returned as character vector containing the error message associated with the most recent I/O operation. If the most recent I/O operation is successful or if you clear it manually, then message is an empty character vector.

Error number, returned as an integer code associated with the error from most recent file I/O operation. If the most recent file I/O operation is successful, then errnum is 0. A nonzero errnum indicates an error:

  • Negative values correspond to MATLAB® error messages.

  • Positive values correspond to C library error messages for your system.

Introduced before R2006a

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