CODEWITHSUNDEEP
c++gccpragma
user2559503
user2559503

Reputation: 289

gcc equivalent of #pragma comment

I'm trying to write a macro that adds a comment to an executable with the gcc compiler. This is not for linking purposes, I simply want to add text comments. Is there a #pragma comment equivalent in gcc for this purpose?

Upvotes: 1

Views: 2320

Answers (3)

Cherry Vanc
Cherry Vanc

Reputation: 831

#ident may be useful. But there are two caveats :

  1. It may not work on all targets.
  2. This is neither a C language standard nor a GNU coding standard

The ‘#ident’ directive takes one argument, a string constant. On some systems, that string constant is copied into a special segment of the object file. On other systems, the directive is ignored. The ‘#sccs’ directive is a synonym for ‘#ident’.

These directives are not part of the C standard, but they are not official GNU extensions either.

https://gcc.gnu.org/onlinedocs/cpp/Other-Directives.html

Upvotes: 0

eerorika
eerorika

Reputation: 238431

If you don't want to clutter the .data section (which is where the static const char[] would go) with comments or conversely, want the comments to be found easily from the .comment section, you can add the comments there with a little bit of inline assembly:

__asm__(".section .comment\n\t"
        ".string \"Hello World\"\n\t"
        ".section .text");

Gcc also has #ident directive which copies the text into an appropriate section if available. In the case of ELF, it would be the .comment section. This solution, even though the directive isn't standard, is probably more portable than the former.

#ident "Hello World"

Upvotes: 2

John Bollinger
John Bollinger

Reputation: 181459

I'm not sure what it means to "add a comment to an executable". Who or what is going to consume, display, or even notice such comments? Nevertheless, if you just want to ensure some string is embedded somewhere in your program, then simply declare it as an ordinary (C) string at file scope.

static const char my_comment[] = "This comment should appear in the compiled executable";

Upvotes: 7

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