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Is there any reason to use the format package rather than printf? Aside from C++ people who claim to hate C needing to save face?

IcyWindows 3y ago
The library overview goes over the reasons fairly succinctly: https://fmt.dev/latest/index.html#overview https://fmt.dev/latest/index.html#overview
pjmlp 3y ago
Other than caring about type safety, and possible CVEs due to misuse of format strings?
- 7jjjjjjj 3y ago
  All decent compilers type check format strings.
  - pjmlp 3y ago
    Assuming decent developers care to enable them in first place.
flohofwoe 3y ago
I like C much more than C++, but even with that must say that https://github.com/fmtlib/fmt https://github.com/fmtlib/fmt is pretty nice (which is the base for std::format). Together with pystring (https://github.com/imageworks/pystring https://github.com/imageworks/pystring) it makes string processing in C++ somewhat bearable (pystring is slow though because it still uses the std::string type which excessively allocates, but at least it's convenient compared to 'raw' C++ string functionality).
amelius 3y ago
The problem with printf and C++ is that you can't do this in general: printf("%d %s", i, obj.convert_to_string()) because the const char* you get from obj.convert_to_string() might be deleted from the heap before printf() is called. And similar issues.
- jstimpfle 3y ago
  AFAIK the lifetime of the temporary is defined as being valid until the statement is done. So even printf("%s\n", obj.to_string().c_str()); should be perfectly fine.
  - gumby 3y ago
    You are correct for C++, though I don't know if C makes this commitment.
    - jstimpfle 3y ago
      This being about C++ and RAII lifetimes, the problem doesn't apply to C. The only similar thing in C would be compound literals. Those have a lifetime like automatic variables (i.e. to the end of the block).
      - gumby 3y ago
        slaps forehead d’oh! My comment was boneheaded in regards to C

IcyWindows 3y ago

The library overview goes over the reasons fairly succinctly: https://fmt.dev/latest/index.html#overview https://fmt.dev/latest/index.html#overview

pjmlp 3y ago

Other than caring about type safety, and possible CVEs due to misuse of format strings?

7jjjjjjj 3y ago
All decent compilers type check format strings.
- pjmlp 3y ago
  Assuming decent developers care to enable them in first place.

flohofwoe 3y ago

I like C much more than C++, but even with that must say that https://github.com/fmtlib/fmt https://github.com/fmtlib/fmt is pretty nice (which is the base for std::format). Together with pystring (https://github.com/imageworks/pystring https://github.com/imageworks/pystring) it makes string processing in C++ somewhat bearable (pystring is slow though because it still uses the std::string type which excessively allocates, but at least it's convenient compared to 'raw' C++ string functionality).

amelius 3y ago

The problem with printf and C++ is that you can't do this in general: printf("%d %s", i, obj.convert_to_string()) because the const char* you get from obj.convert_to_string() might be deleted from the heap before printf() is called. And similar issues.

jstimpfle 3y ago
AFAIK the lifetime of the temporary is defined as being valid until the statement is done. So even printf("%s\n", obj.to_string().c_str()); should be perfectly fine.
- gumby 3y ago
  You are correct for C++, though I don't know if C makes this commitment.
  - jstimpfle 3y ago
    This being about C++ and RAII lifetimes, the problem doesn't apply to C. The only similar thing in C would be compound literals. Those have a lifetime like automatic variables (i.e. to the end of the block).
    - gumby 3y ago
      slaps forehead d’oh! My comment was boneheaded in regards to C