# $$\text{FileReadReal}$$¶

You can use the the $$\text{FileReadReal}$$ function to read a single single precision or double precision real value.

You can use the \filereadreal backslash command to insert this function.

The following variants of this function are available:

• $$\text{tuple } \text{FileReadReal} \left ( \text{<file number>} \right )$$

• $$\text{tuple } \text{FileReadReal} \left ( \text{<file number>}, \text{<size/endian>} \right )$$

The $$\text{<file number>}$$ parameter is an integer value returned by one of the $$\text{FileOpen}\ldots$$ functions. The $$\text{<size/endian>}$$ parameter indicates how the real value to be read is encoded in the file.

If the $$\text{<size/endian>}$$ value is not included or is 0, then the $$\text{FileReadReal}$$ function assumes that the real is encoded as a string, either with a fixed point representation such as -123.4 or an exponent representation such as -1.234E2. The real value can be positive or negative, including a leading + character and the exponent character E can be upper or lower case. In this mode, the $$\text{FileReadReal}$$ function will read up-to but excluding the first non-digit character.

If the $$\text{<size/endian>}$$ value is +4 or +8, then the $$\text{FileReadReal}$$ function will read the real value in little-endian single or double precision format conforming to IEEE 754-2008. That is, the least significant bit of the mantissa will be at the first (lowest) position in the file.

If the $$\text{<size/endian>}$$ value is -4 or -8, then the $$\text{FileReadReal}$$ function will real the real value in big-endian single or double precision format conforming to IEEE 754-2008. That is, the sign bit will be at the most significant bit of the byte at the first (lowest) position in the file.

The $$\text{FileReadReal}$$ function will return a tuple containing two entries:

• The real value read from the file.

• A boolean holding true on success or false on error.

The Figure 134 shows how you can use the $$\text{FileReadReal}$$ function.