std::jmp_buf
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jmp_buf
Defined in header
<csetjmp>
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
Run this code
#include <array> #include <cmath> #include <csetjmp> #include <cstdlib> #include <format> #include <iostream> 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
[edit] See also
C documentation for jmp_buf