4 ms·

Who Needs Main() Anyway?

rramadass 4y ago
Is this what passes for "technical know-how" nowadays? Just read Hongjiu Lu's classic paper ELF: From The Programmer's Perspective to get an idea of how everything comes together in C/C++ land.
- sargstuff 4y ago
  But in today's non-programmer post-covid world, ELF is seasonal, COFF is year round. edit: COFF phoneticly eqivalent to cough.
jeffreygoesto 4y ago
Sigh. Wait until she learns about the static initialization order fiasco...
- moloch-hai 4y ago
  She knows. Code where it matters is wrong.
  - sargstuff 4y ago
    Sounds like a have to C it to believe it.
- deleted 4y ago
  [deleted]
xjwm 4y ago
I've written code like this in C to create library functions that will be linked in to other projects, but where there is no 'main' function in the C file. Do people use C++ the same way, or is it best practice to include 'main?'
- MathMonkeyMan 4y ago
  It's the same as in C. The observation here is that variables with static storage duration can be initialized by running user code before main() begins.
  - xjwm 4y ago
    Oh! Thank you. That makes much more sense now.
  - colejohnson66 4y ago
    It’s also the same in .NET. If your Main() function references types that have a static constructor, the constructors could run before Main(). It’s a surprising thing when one first discovers it, but it makes a lot of sense.
moloch-hai 4y ago
It didn't crash until after its work was done. It could even have trapped the segfault and exited cleanly.
- marssaxman 4y ago
  Couldn't just call exit(0)?
  - moloch-hai 4y ago
    Maybe, or _exit().
0xcafefood 4y ago
A more useful application of this same idea ("you can do stuff during static initialization") is for building a static registry. https://artificial-mind.net/blog/2020/10/17/static-registration-macro https://artificial-mind.net/blog/2020/10/17/static-registrat... gives a good overview.
sargstuff 4y ago
[1] p.99 information might be of interest cc -Wl,-m main.c > main.linker.map related search terms: _crtStartUp crt0 crt1 [1] : https://progforperf.github.io/Expert_C_Programming.pdf https://progforperf.github.io/Expert_C_Programming.pdf

Is this what passes for "technical know-how" nowadays? Just read Hongjiu Lu's classic paper ELF: From The Programmer's Perspective to get an idea of how everything comes together in C/C++ land.

sargstuff 4y ago
But in today's non-programmer post-covid world, ELF is seasonal, COFF is year round. edit: COFF phoneticly eqivalent to cough.

jeffreygoesto 4y ago

Sigh. Wait until she learns about the static initialization order fiasco...

moloch-hai 4y ago
She knows. Code where it matters is wrong.
- sargstuff 4y ago
  Sounds like a have to C it to believe it.
deleted 4y ago
[deleted]

xjwm 4y ago

I've written code like this in C to create library functions that will be linked in to other projects, but where there is no 'main' function in the C file. Do people use C++ the same way, or is it best practice to include 'main?'

MathMonkeyMan 4y ago
It's the same as in C. The observation here is that variables with static storage duration can be initialized by running user code before main() begins.
- xjwm 4y ago
  Oh! Thank you. That makes much more sense now.
- colejohnson66 4y ago
  It’s also the same in .NET. If your Main() function references types that have a static constructor, the constructors could run before Main(). It’s a surprising thing when one first discovers it, but it makes a lot of sense.

moloch-hai 4y ago

It didn't crash until after its work was done. It could even have trapped the segfault and exited cleanly.

marssaxman 4y ago
Couldn't just call exit(0)?
- moloch-hai 4y ago
  Maybe, or _exit().

0xcafefood 4y ago

A more useful application of this same idea ("you can do stuff during static initialization") is for building a static registry. https://artificial-mind.net/blog/2020/10/17/static-registration-macro https://artificial-mind.net/blog/2020/10/17/static-registrat... gives a good overview.

sargstuff 4y ago

[1] p.99 information might be of interest cc -Wl,-m main.c > main.linker.map related search terms: _crtStartUp crt0 crt1 [1] : https://progforperf.github.io/Expert_C_Programming.pdf https://progforperf.github.io/Expert_C_Programming.pdf