Nov 6, 2017 · Now if the value of a variable of type signed char is 127, and you add 1, what happens then? What is the new value? You don't know, because you have a signed integer overflow, which leads to undefined behavior. The problem is the same with int (which is really signed int), the values are just larger.

May 7, 2016 · In fact, because the C standard says signed integer overflow is undefined, some compilers (like GCC) will optimize away the above check when optimization flags are set, because the compiler assumes a signed overflow is impossible. This totally breaks the attempt to check for overflow. So, another possible way to check for overflow would be:

Apr 6, 2023 · The integer underflow occurs when a number is smaller than the minimum value the data type can hold. We deal mainly with these data types to store integers in C++. These are: signed int: The signed int data type ranges between -2,147,483,648 to 2,147,483,647 (-10 9 to 10 9). unsigned int: The unsigned int data type ranges between 0 to ...

As we know, signed integer overflow is undefined behavior. But there is something interesting in C++11 cstdint documentation: signed integer type with width of exactly 8, 16, 32 and 64 bits respectively with no padding bits and using 2's complement for negative values (provided only if the implementation directly supports the type) See link

Jan 21, 2020 · It's worth pointing out that integer overflow and underflow are undefined only for SIGNED types. For unsigned integers, overflow safely occurs as modulo arithmetic.

Make signed integer operations well-defined, like unsigned integer operations: they produce the n low-order bits of the true result. The highest of those n bits is the sign bit of the result. With -fwrapv, these out-of-range operations are not considered overflow, so (strictly speaking) integer overflow never happens.

Signed integer overflow is undefined behavior 36. Consequently, implementations have considerable latitude in how they deal with signed integer overflow. (See MSC15-C. Do not depend on undefined behavior.) An implementation that defines signed integer types as being modulo, for example, need not detect integer overflow. Implementations may also trap on …

Jan 24, 2025 · This post explores signed integer overflow and undefined behavior in C, highlighting an example where GCC produces unexpected outputs. Understanding these concepts is crucial for writing robust code.

Jan 24, 2025 · Understanding Signed Integer Overflow in C: A Deep Dive into GCC Compiler Behavior When working with C, a language known for its close-to-the-metal capabilities, programmers often encounter the quirks of low-level operations, especially when dealing with signed integers and overflow. This blog post aims to elucidate the behavior you’re observing …

Jan 11, 2010 · Signed integer overflow is undefined according to both C and C++ standards. There's no way to accomplish what you want without a specific platform in mind.