C array declaration with inline assembly

Question

I recently came upon this snippet:

extern const uint8_t server_root_cert_pem_start[] asm("_binary_server_root_cert_pem_start");
//                                                ^^^^^^^^^^^^^ what's going on here?

in the esp-idf examples(line 74). I cannot understand the declaration, and my online search hasn't been successful. My best guess would be that this code:

• Uses uint8_t as a replacement for char since they have the same size (1 byte). No clue why though

• Ultimately declares a string (a const char array) by inferring the array size from the string length whose length has been specified outside our module

Even if my assumptions are correct, I fail to understand why it's written this way or what happens with "null termination" in this case. So the actual questions:

• What is this code doing?
• Why is it doing it this way (advantages)?
• Are there any implications that differentiate it from a simple C-style declaration?

Answer 1

This is compiler dependend. However my guess is that this code declare an array named server_root_cert_pem_start and binds it to another symbol (memory location) _binary_server_root_cert_pem_start probably defined elsewhere (in an assembly file?)