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digitalmars.D.learn - Druntime: Changing the underlying C Standard Library

reply Sebastian Trent <null null.com> writes:
Hello,

I'm writing an operating system in D for some exotic hardware. I 
understand the D runtime environment depends on a C stdlib being 
available (at compile time or run time?)

As a consequence of the hardware, I need to use our own C std lib 
for the operating system. How can I set about directing the 
compiler (or run-time) to non-default implementation?

Alternatively, I infer there's nothing breaking about replacing 
all of core.stdc with an implementation written in -betterC?

Thanks,


ST.
Jan 11
parent Adam D. Ruppe <destructionator gmail.com> writes:
On Friday, 12 January 2018 at 03:21:15 UTC, Sebastian Trent wrote:
 I'm writing an operating system in D for some exotic hardware. 
 I understand the D runtime environment depends on a C stdlib 
 being available (at compile time or run time?)
both
 As a consequence of the hardware, I need to use our own C std 
 lib for the operating system. How can I set about directing the 
 compiler (or run-time) to non-default implementation?
Same way you would in C itself: instruct the linker to use your runtime instead. On Linux, something like `-L-nostdlib -L-lmy_c_library` should do it. The -L option to dmd passes the rest of the option down to the linker (gcc, which then passes it to ld), so that `-nostdlib` flag is actually one of gcc's.
 Alternatively, I infer there's nothing breaking about replacing 
 all of core.stdc with an implementation written in -betterC?
core.stdc has no code per se, it is just function prototypes to access the C library. The C library itself is provided externally by the linker.
Jan 11