Re: gcc compiles assert() to code that requires linking withgcc

[Martin Buchholz <martin at xemacs dot org>]

>>>>> "MM" == Mark Mitchell <mark@codesourcery.com> writes:

MM> There are two issues here:

MM>   - Should GCC compiled libraries have, under any circumstances,
MM>     dependencies on libgcc?

MM>   - Should using `assert' result in a dependency on libgcc?

MM> The answer to the first question is definitely yes.  For example, GCC
MM> uses libgcc to provide floating point emulation for processors that do
MM> not support floating point.  GCC uses libgcc to provide support for
MM> exception-handling and global initialization in C++ and Java, as
MM> appropriate.

Agreed.  Here I am only concerned with C.  C++ is much harder, and I
can understand why achieving binary compatibility with C++ might not
be achievable.  But C is much more important, because the prospect of
binary compatibility is one of the most important reasons for choosing
C over C++ in the first place (the other reason, C++ compilation
turning C warnings into errors, is an especial problem for free
software that needs to compile in hostile environments (like configure
scripts on strange machines)).

Many an author of a portable free software library chooses C, eschews
newfangled stuff like `long long', etc in the expectation that library
users be able to create binaries suitable for distribution to others
sharing the same platform.  gcc's assert() should not be a hindrance.

MM> However, the fewer dependencies on libgcc the better, all things being
MM> equal.  

Yes.

MM> If you can implement assert in a way that is not detrimental in
MM> other ways, but does provide the benefit that simply using
MM> `assert' does not pull in libgcc, that sounds fine to me.  You
MM> still should not depend on being able to avoid linking in libgcc;
MM> it may well be needed for other purposes.

Understood.

MM> You mention the practices of other compiler vendors.  Many compiler
MM> vendors include functionality equivalent to libgcc in the OS C
MM> library.  GCC cannot do that, in general, since the GCC developers
MM> have no control over the OS C library.  So, a separate library is used
MM> instead.

MM> In short, when you imply that the output of most compilers works
MM> without linking in a special library, you're incorrect; it's just that
MM> the library you must link in is the C library, which you probably
MM> wanted to link in anyhow.

A Solaris without libc is probably not Solaris - there was the option
of running Sparc-Linux, after all.