• tcb (12/12) Jul 15 2018 I've been trying to compile a trivial program (extern C int
• kinke (5/7) Jul 15 2018 This works for me:
• Walter Bright (5/7) Jul 15 2018 Declaring a C function called "main" causes the C runtime library to be ...
• tcb (1/1) Jul 15 2018 Thank you both, that clarifies a lot!
• Walter Bright (6/7) Jul 15 2018 You can set the start address with the DMC C compiler using a #pragma:
• Jonathan Marler (8/20) Jul 16 2018 I recently created an issue that included an example that allows

tcb <tcb pleasenoemailspam.net> writes:

I've been trying to compile a trivial program (extern C int 
main() {return 0;}) without linking parts of the C runtime with 
no success.

I compile with dmd -debuglib= -defaultlib= -v -L=/INFORMATION 
-betterC but optlink shows a lot of things from snn.lib being 
pulled in and the resultant executable is about 12kb. I also 
replaced object.d with an empty module.

If I pass /nodefaultlib to the linker I get warning 23: no stack 
and __acrtused_con is undefined so the linker fails with no start 
address.

Is it possible to completely remove the C runtime on windows, and 
if so how? Sorry for the sloppily formatted post.

kinke <noone nowhere.com> writes:

On Sunday, 15 July 2018 at 20:29:29 UTC, tcb wrote:
 Is it possible to completely remove the C runtime on windows, 
 and if so how?

This works for me:

extern(C) int mainCRTStartup() { return 0; }

dmd -m32mscoff -betterC -L/subsystem:CONSOLE main.d

=> 1.5 kB .exe.

Walter Bright <newshound2 digitalmars.com> writes:

On 7/15/2018 1:29 PM, tcb wrote:
 I've been trying to compile a trivial program (extern C int main() {return
0;}) 
 without linking parts of the C runtime with no success.

Declaring a C function called "main" causes the C runtime library to be pulled 
in. After all, main() is not the program entry point, as main() requires a 
number of things to be set up first (such as argc and argv).

Call the function something else, and compile with -betterC.

tcb <tcb pleasenoemailspam.net> writes:

Thank you both, that clarifies a lot!

Walter Bright <newshound2 digitalmars.com> writes:

On 7/15/2018 2:46 PM, tcb wrote:
 Thank you both, that clarifies a lot!

You can set the start address with the DMC C compiler using a #pragma:

   https://www.digitalmars.com/ctg/pragmas.html#startaddress

but currently that isn't directly settable with the DMD compiler.

You can see how it is used in this file of the DMC runtime library:

   https://github.com/DigitalMars/dmc/blob/master/src/WIN32/constart.c#L88

Jonathan Marler <johnnymarler gmail.com> writes:

On Sunday, 15 July 2018 at 20:29:29 UTC, tcb wrote:
 I've been trying to compile a trivial program (extern C int 
 main() {return 0;}) without linking parts of the C runtime with 
 no success.

 I compile with dmd -debuglib= -defaultlib= -v -L=/INFORMATION 
 -betterC but optlink shows a lot of things from snn.lib being 
 pulled in and the resultant executable is about 12kb. I also 
 replaced object.d with an empty module.

 If I pass /nodefaultlib to the linker I get warning 23: no 
 stack and __acrtused_con is undefined so the linker fails with 
 no start address.

 Is it possible to completely remove the C runtime on windows, 
 and if so how? Sorry for the sloppily formatted post.

I recently created an issue that included an example that allows 
you to compile a Hello World program on linux x64 without the c 
standard library, druntime or phobos.

https://issues.dlang.org/show_bug.cgi?id=19078

You can modify it to run on windows as well.  I'm not sure if the 
_start assembly implementation would be the same on windows.  Try 
it out and let me know how it works.