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copied!<p>You are not clear if you mean floating point literal as part of the source code (for the compiler to parse into architecture-dependent binary representation), or scanned by library functions, such as <code>scanf()</code>, <code>atof()</code>, <code>strtol()</code>, <code>strtod()</code> and <code>strtold()</code> (at run-time, to convert to in-memory <code>float</code>, <code>double</code> or <code>long double</code> value).</p> <p>In the first case, it is part of ISO/IEC 9899:1999 (ISO C99), §6.4.4.2 "Floating constants". It defines both the lexicon and how it should be interpreted.</p> <p>In the second case, the behavior of the library functions are defined in §7.20.1 "Numeric conversion functions".</p> <p>I don't have a hard copy of the previous standard (ANSI C, 1989), but I'm pretty sure it also defines very precisely how floating point numbers are parsed and converted.</p> <p>In the case you want to know if there is a standard to represent these values in binary format, in-memory, the answer is no. The C language is intended to be close to the architecture, and not impose constraints over it. So the in-memory representation is always architecture-dependent. But the C standard defines how arithmetic should be performed over floating point values. It follows IEC 60559 standard. In the ISO C99 standard, it is described in Annex F (normative), "IEC 60559 floating-point arithmetic". The implementation may or may not implement this standard. If it does, it must define the <code>__STDC_IEC_559__</code> preprocessor name.</p>

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