C

What is C and what does it do?

C is a general-purpose language with a compact set of abstractions over memory, values, control flow, and function calls. A compiler translates C source for a target platform, and a linker combines the resulting objects with the libraries the program needs. Operating systems, embedded software, language runtimes, and native libraries often use C because it can stay close to their binary interfaces.

C can be read as a set of explicit contracts. The language provides control over representation and access, but size, lifetime, and valid ranges remain the programmer's responsibility.

A pointer is not a container

A pointer identifies a location. It does not automatically carry the number of elements that may be read from that location. An address and its valid length should therefore stay together at every function boundary.

#include <stddef.h>

int sum(const int *values, size_t count)
{
    int total = 0;
    for (size_t i = 0; i < count; ++i) {
        total += values[i];
    }
    return total;
}

The loop is ordinary on purpose. Its bounds, accumulator, and reads are visible, so the caller's responsibility is easy to state: values must refer to at least count readable integers.

Ownership needs a sentence

C does not decide who releases dynamically acquired memory or how long a borrowed pointer remains valid. That rule should be expressible in plain language before the implementation is written.

An ownership rule is complete only when it names who creates a resource, who may borrow it, and who releases it.

Each resource contract should answer:

• Can a null or empty value cross this boundary?
• Does the receiver borrow the resource or take ownership?
• Which function performs the matching cleanup?
• What happens when an operation fails halfway through?

The cost model stays visible

C is useful when representation is part of the problem, but visibility is not the same as automatic speed.

Decision	What still needs verification
Contiguous array	Bounds, alignment, and element count
Manual allocation	Failure, ownership, and release path
Native call	ABI, data layout, and error convention
Bit-level operation	Integer width and defined behavior

This level of control is justified only when it clarifies a real systems constraint. If a managed runtime can remove those responsibilities without hiding an important requirement, it usually offers the smaller risk surface.