std::jmp_buf - cppreference.com (original) (raw)
| | | | | ------------------------------------- | | | | typedef /* unspecified */ jmp_buf; | | |
The std::jmp_buf type is an array type suitable for storing information to restore a calling environment. The stored information is sufficient to restore execution at the correct block of the program and invocation of that block. The state of floating-point status flags, or open files, or any other data is not stored in an object of type std::jmp_buf.
[edit] Example
#include #include #include #include #include #include std::jmp_buf solver_error_handler; std::array<double, 2> solve_quadratic_equation(double a, double b, double c) { const double discriminant = b * b - 4.0 * a * c; if (discriminant < 0) std::longjmp(solver_error_handler, true); // Go to error handler const double delta = std::sqrt(discriminant) / (2.0 * a); const double argmin = -b / (2.0 * a); return {argmin - delta, argmin + delta}; } void show_quadratic_equation_solution(double a, double b, double c) { std::cout << std::format("Solving {}x² + {}x + {} = 0...\n", a, b, c); auto [x_0, x_1] = solve_quadratic_equation(a, b, c); std::cout << std::format("x₁ = {}, x₂ = {}\n\n", x_0, x_1); } int main() { if (setjmp(solver_error_handler)) { // Error handler for solver std::cout << "No real solution\n"; return EXIT_FAILURE; } for (auto [a, b, c] : {std::array{1, -3, 2}, {2, -3, -2}, {1, 2, 3}}) show_quadratic_equation_solution(a, b, c); return EXIT_SUCCESS; }
Output:
Solving 1x² + -3x + 2 = 0... x₁ = 1, x₂ = 2 Solving 2x² + -3x + -2 = 0... x₁ = -0.5, x₂ = 2 Solving 1x² + 2x + 3 = 0... No real solution