NSPR provides functions that convert double-precision floating point numbers to and from their character string representations.
These conversion functions were originally written by David M. Gay of AT&T. They use IEEE double-precision (not IEEE double-extended) arithmetic.
The header file
prdtoa.h declares these functions. The functions are:
Gay's implementation is inspired by these two papers.
 William D. Clinger, "How to Read Floating Point Numbers Accurately," Proc. ACM SIGPLAN '90, pp. 92-101.
 Guy L. Steele, Jr. and Jon L. White, "How to Print Floating-Point Numbers Accurately," Proc. ACM SIGPLAN '90, pp. 112-126.