libmathexpr

This BSD licensed, C library evaluates basic single variable infix math expressions. Some built-in constants and functions are supported. Building depends on lex, C99. Version 0.1, use at own risk.

Example

MathExpr e;
char errbuf[256];
const char *expr = "sin(PI)^2 + (5 * (t - 1))"; // variable t
if (math_expr_init(&e, expr, sizeof(expr), errbuf, sizeof(errbuf)) < 0) {
    fprintf(stderr, "Compile error: %s", errbuf);
    exit(1);
}
double result;
math_expr_eval(&e, 42, &result);