If you’ve spent any time in the weeds of C programming, you know the dread of seeing a single asterisk. Two asterisks? That’s usually where people start questioning their career choices. But when you hit pointer to pointer to pointer in c, things get weird. It’s like a hall of mirrors. You’re looking at a memory address that holds the address of another address, which—believe it or not—eventually points to some actual data.
Most tutorials make this sound like a logic puzzle. It isn't. It’s just bookkeeping.
I remember the first time I saw char ***argv in a legacy codebase. I thought it was a typo. It wasn’t. It was a sophisticated way to handle a dynamic list of strings where the list itself was also dynamic. C doesn't hold your hand. It expects you to know exactly where every byte lives in the RAM. If you lose track of one level of indirection, the whole thing crashes with a segmentation fault that tells you absolutely nothing useful.
The Mental Model for Triple Indirection
Think about a scavenger hunt.
You have a piece of paper. That paper tells you where to find a box. Inside that box is another piece of paper. That paper tells you where a second box is. Inside the second box? Another paper. Finally, that last paper tells you where the treasure is buried.
In C syntax, it looks like this: int ***ptr;.
The int tells us the treasure is an integer. The three stars tell us how many boxes we have to open before we get to it. It sounds inefficient, and frankly, if you’re using it for simple math, it is. But in systems programming, particularly when dealing with complex data structures like 3D arrays or reallocating memory for a list of pointers, it’s a tool you can't really ignore.
Why on Earth Use pointer to pointer to pointer in c?
You might be wondering why anyone would do this to themselves. Why not just use a struct? Well, sometimes you're working within the constraints of an existing API or you're managing a very specific type of memory allocation.
Take a look at a 2D array of strings.
A string in C is just a char*.
A list of strings is a char**.
Now, imagine you want a function to modify that list of strings—maybe resize it or sort it in a way that requires reallocating the top-level pointer. To change the original char** inside a function, you have to pass its address. That gives you a char***.
It’s about ownership.
When you pass a variable to a function in C, the function gets a copy. If you want the function to change the original variable, you pass a pointer. If that original variable is already a pointer to a pointer, then you’re officially in triple-pointer territory. This happens constantly in specialized libraries like FFmpeg or when interfacing with low-level kernel drivers where memory buffers are passed around in layers.
The Syntax Nightmare
Let's get practical. How do you actually write this without the compiler screaming at you?
int value = 42;
int *p1 = &value;
int **p2 = &p1;
int ***p3 = &p2;
To get the value back, you have to "dereference" it three times: ***p3.
Each star "opens a box." If you only use two stars (**p3), you aren't looking at the number 42. You're looking at the memory address of p1. If you use one star (*p3), you're looking at the address of p2. It’s easy to see why people get lost. One wrong move and you’re trying to treat a memory address as an integer, which is a fast track to a "Bus Error" or a "Segfault."
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Dynamic 3D Memory Allocation
This is where the real world hits.
If you want to create a 3D grid in memory—let’s say for a physics simulation or a basic voxel game engine—you could declare it statically like int grid[10][10][10]. That’s boring. And it’s stuck on the stack. If you need it on the heap because the size changes at runtime, you have to use malloc().
- First, you allocate the "level 3" pointers.
- Then, for each of those, you allocate "level 2" pointers.
- Finally, you allocate the actual "level 1" data blocks.
It’s a nested loop of malloc calls. And God help you when it’s time to free() that memory. You have to do it in the exact reverse order. If you free the top-level pointer first, you’ve just orphaned all the sub-pointers, creating a memory leak that will eat your RAM alive. This is the kind of stuff that keeps C programmers up at night.
Common Pitfalls and How to Not Crash
The biggest mistake? Forgetting that pointers have a size. On a 64-bit system, every pointer is 8 bytes. It doesn't matter if it's pointing to a char (1 byte) or a massive struct (1000 bytes). The pointer itself is always the same size.
When you use pointer to pointer to pointer in c, you are managing a chain of 8-byte addresses.
- Initialization: Never leave a triple pointer uninitialized.
int ***ptr = NULL;is your friend. - The "Double Free" Trap: If you copy a triple pointer and free one, the other becomes a "dangling pointer." It still thinks it points to valid boxes, but the boxes are gone.
- Pointer Arithmetic: Just don't. Seriously. Doing
ptr++on a triple pointer moves the address by 8 bytes (the size of a pointer), which might be what you want, but it's usually the start of a very long debugging session.
Does Anyone Actually Use This in 2026?
Honestly, in modern application development, we try to avoid this. C++ has references and smart pointers. Rust has ownership and borrowing rules that make this kind of manual memory juggling look like madness. But C is the foundation.
If you're writing a compiler, a high-performance database engine like PostgreSQL, or working on the Linux Kernel, you'll see this stuff. It’s the raw reality of how computers work. There is no abstraction. There is no garbage collector to pick up your mess. It’s just you and the memory map.
Understanding triple pointers is a rite of passage. It proves you understand how the stack and heap actually interact. It’s not just about the code; it’s about the mental map of the machine.
Actionable Steps for Mastering Indirection
If you’re staring at a *** and feeling dizzy, stop coding and grab a piece of paper.
Draw the boxes. Literally. Draw a box for the value, a box for the pointer, a box for the next pointer, and a box for the third pointer. Draw arrows between them. If your arrows don't form a clear line to the data, your logic is broken.
- Validate at every step: Use
assert(ptr != NULL)before dereferencing. It takes two seconds and saves two hours of debugging. - Use typedefs: Sometimes, it’s cleaner to
typedef char** Page;and then usePage *book;. It hides one level of the stars and makes the code readable for humans who didn't write it. - Compiler warnings are law: Turn on
-Wall -Wextra. If the compiler says you have a "pointer type mismatch," believe it. It’s smarter than you are about memory offsets. - Valgrind is mandatory: If you’re doing dynamic allocation with triple pointers, run your code through Valgrind. It will catch the leaks you inevitably missed in your
free()loops.
Mastering pointer to pointer to pointer in c isn't about being a genius. It's about being meticulous. Treat the memory with respect, track your allocations, and always—always—draw the map before you start the hunt.