Linux SIGFPE — Floating Point Exception (Arithmetic Error)

Linux SIGFPE (signal 8) occurs from arithmetic errors including integer division by zero, integer overflow, and floating-point exceptions. This guide covers everything you need to know about this topic, including common causes, step-by-step solutions, and answers to frequently asked questions.

Here are the key things to understand: SIGFPE (signal 8) is misleadingly named — it covers ALL arithmetic errors, not just floating-point. Most common cause: integer division by zero. Integer overflow does not normally raise SIGFPE unless compiled with -ftrapv (GCC). Floating-point operations normally produce Inf/NaN instead of SIGFPE by default. SIGFPE from floating-point only occurs if FP exceptions are explicitly enabled (feenableexcept). Understanding these fundamentals will help you diagnose and resolve this issue more effectively.

The most common reasons this occurs include: Integer division by zero (/ or % operator with divisor = 0). Integer overflow with -ftrapv compiler flag enabled. Floating-point exception explicitly enabled with feenableexcept(). INT_MIN / -1 causing overflow in two's complement arithmetic. Modulo by zero (x % 0). Identifying the root cause is the first step toward finding the right solution.

To resolve this, follow these recommended steps: Use GDB to find the exact line: gdb ./program, run, then 'bt' at SIGFPE. Add division-by-zero guards in code: if (divisor != 0) result = x / divisor;. For C code: compile with -fsanitize=integer for runtime overflow detection. Check for INT_MIN / -1 edge case (yields INT_MIN + 1 which overflows). Review floating-point exception settings: check for feenableexcept() calls. If these steps do not resolve the issue, consider consulting additional resources or a qualified professional.

This article is part of our Linux Error Codes collection on Error Codes Wiki. We provide comprehensive, up-to-date information to help you find solutions quickly.