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Arm Compiler Arm C and C++ Libraries and Floating-Point Support User Guide : _fisatty()


Defined in stdio.h, the _fisatty() function determines whether the given stdio stream is attached to a terminal device or a normal file.

It calls the _sys_istty() low-level function on the underlying file handle.

This function is not part of the C library standard, but the Arm® C library supports it as an extension.


int _fisatty(FILE *stream);

The return value indicates the stream destination:


A file.


A terminal.


An error.