On Tuesday, 2 August 2016 at 17:25:21 UTC, Steven Schveighoffer
wrote:
On 8/2/16 1:04 PM, Rufus Smith wrote:
On Tuesday, 2 August 2016 at 16:30:08 UTC, Adam D. Ruppe wrote:
On Tuesday, 2 August 2016 at 16:21:07 UTC, Rufus Smith wrote:
How does one use C main? extern C?
extern(C) int main()
should do it
It doesn't seem to be that easy!
https://wiki.dlang.org/Runtime_internals
This is just explaining how the runtime currently works, not
how you should override it.
It's really easy actually. Example:
$ cat main.c
#include <stdio.h>
extern int rt_init();
extern void d_func();
int main(int argc, char *argv[])
{
printf("hello from C!\n");
rt_init();
printf("done initializing runtime\n");
d_func();
}
$ cat dmain.d
extern(C) void d_func()
{
import std.stdio;
writeln("hello from D!");
}
shared static this()
{
import std.stdio;
writeln("doing some pre-run init!");
}
$ gcc -c main.c
$ dmd dmain.d main.o
$ ./dmain
hello from C!
doing some pre-run init!
done initializing runtime
hello from D!
-Steve
When I do this in my project and try to link in the lib or obj
created from the C project, I get "entry point must be defined"
error. I tried to add both to the "command line".
If I don't have a main function in D, I get all kinds of
unresolved externals. Not sure why, but it seems to not import in
the runtime when there is no main defined.
Basically I created a side C++ project, copied your code in to
the main.cpp. I then added the obj file to the linker command
line path. Then I get the missing entry point error. It is very
similar to yours, just using VisualD and windows.
Seems like it would be easier just to create a wrapper process
and use shared memory to transfer data between them ;/
For example, if I just create a new D project. Add a new cpp file
and paste your C code in, paste the D code in the empty D file,
and try to compile, I get:
main.cpp
main.obj : error LNK2019: unresolved external symbol "int __cdecl
rt_init(void)" (?rt_init@@YAHXZ) referenced in function main
main.obj : error LNK2019: unresolved external symbol "void
__cdecl d_func(void)" (?d_func@@YAXXZ) referenced in function main
CMain.obj : error LNK2001: unresolved external symbol
_D14TypeInfo_Const6__vtblZ
CMain.obj : error LNK2019: unresolved external symbol _d_throwc
referenced in function
_D3std9exception143__T12errnoEnforceTiVAyaa54_423a5c444c616e675c646d64325c77696e646f77735c62696e5c2e2e5c2e2e5c7372635c70686f626f735c7374645c737464696f2e64Vmi2543Z12errnoEnforceFNfiLAyaZi (@safe int std.exception.errnoEnforce!(int, "dmd2\windows\bin\..\..\src\phobos\std\stdio.d", 2543uL).errnoEnforce(int, lazy immutable(char)[]))
CMain.obj : error LNK2001: unresolved external symbol
_D12TypeInfo_Aya6__initZ
CMain.obj : error LNK2019: unresolved external symbol
_D3std3utf12isValidDcharFNaNbNiNfwZb referenced in function
_D3std5stdio4File17LockingTextWriter10__T3putTwZ3putMFNbNiNfwZv
CMain.obj : error LNK2019: unresolved external symbol
_D3std9exception14ErrnoException6__ctorMFNeAyaAyamZC3std9exception14ErrnoException (@trusted std.exception.ErrnoException std.exception.ErrnoException.__ctor(immutable(char)[], immutable(char)[], ulong)) referenced in function _D3std9exception143__T12errnoEnforceTiVAyaa54_423a5c444c616e675c646d64325c77696e646f77735c62696e5c2e2e5c2e2e5c7372635c70686f626f735c7374645c737464696f2e64Vmi2543Z12errnoEnforceFNfiLAyaZi (@safe int std.exception.errnoEnforce!(int, "dmd2\windows\bin\..\..\src\phobos\std\stdio.d", 2543uL).errnoEnforce(int, lazy immutable(char)[]))
CMain.obj : error LNK2019: unresolved external symbol _aApplycd1
referenced in function
_D3std5stdio4File17LockingTextWriter12__T3putTAyaZ3putMFNfAyaZv
(@safe void
std.stdio.File.LockingTextWriter.put!(immutable(char)[]).put(immutable(char)[]))
CMain.obj : error LNK2019: unresolved external symbol
_D3std5stdio8__assertFiZv (void std.stdio.__assert(int))
referenced in function
_D3std5stdio4File17LockingTextWriter10__T3putTwZ3putMFNbNiNfwZv
CMain.obj : error LNK2019: unresolved external symbol
_D3std5stdio4File17lockingTextWriterMFNfZS3std5stdio4File17LockingTextWriter (@safe std.stdio.File.LockingTextWriter std.stdio.File.lockingTextWriter()) referenced in function _D3std5stdio16__T7writelnTAyaZ7writelnFNfAyaZv (@safe void std.stdio.writeln!(immutable(char)[]).writeln(immutable(char)[]))
CMain.obj : error LNK2001: unresolved external symbol
_D3std5stdio12__ModuleInfoZ
CMain.obj : error LNK2019: unresolved external symbol
_D3std5stdio13trustedStdoutFNdNeZS3std5stdio4File (@property
@trusted std.stdio.File std.stdio.trustedStdout()) referenced in
function _D3std5stdio16__T7writelnTAyaZ7writelnFNfAyaZv (@safe
void
std.stdio.writeln!(immutable(char)[]).writeln(immutable(char)[]))
CMain.obj : error LNK2019: unresolved external symbol
_D3std3utf6toUTF8FNaNbNiNfNkJG4awZAa referenced in function
_D3std5stdio4File17LockingTextWriter10__T3putTwZ3putMFNbNiNfwZv
CMain.obj : error LNK2019: unresolved external symbol
_d_assert_msg referenced in function
_D3std5stdio4File17LockingTextWriter12__T3putTAyaZ3putMFNfAyaZv
(@safe void
std.stdio.File.LockingTextWriter.put!(immutable(char)[]).put(immutable(char)[]))
CMain.obj : error LNK2001: unresolved external symbol
_D10TypeInfo_k6__initZ
CMain.obj : error LNK2019: unresolved external symbol
_D3std9exception14ErrnoException7__ClassZ referenced in function
_D3std9exception143__T12errnoEnforceTiVAyaa54_423a5c444c616e675c646d64325c77696e646f77735c62696e5c2e2e5c2e2e5c7372635c70686f626f735c7374645c737464696f2e64Vmi2543Z12errnoEnforceFNfiLAyaZi (@safe int std.exception.errnoEnforce!(int, "dmd2\windows\bin\..\..\src\phobos\std\stdio.d", 2543uL).errnoEnforce(int, lazy immutable(char)[]))
CMain.obj : error LNK2019: unresolved external symbol
_D3std5stdio4File6__dtorMFNfZv (@safe void
std.stdio.File.__dtor()) referenced in function
_D3std5stdio16__T7writelnTAyaZ7writelnFNfAyaZv (@safe void
std.stdio.writeln!(immutable(char)[]).writeln(immutable(char)[]))
CMain.obj : error LNK2019: unresolved external symbol _d_newclass
referenced in function
_D3std9exception143__T12errnoEnforceTiVAyaa54_423a5c444c616e675c646d64325c77696e646f77735c62696e5c2e2e5c2e2e5c7372635c70686f626f735c7374645c737464696f2e64Vmi2543Z12errnoEnforceFNfiLAyaZi (@safe int std.exception.errnoEnforce!(int, "dmd2\windows\bin\..\..\src\phobos\std\stdio.d", 2543uL).errnoEnforce(int, lazy immutable(char)[]))
CMain.obj : error LNK2019: unresolved external symbol
_D3std5stdio7__arrayZ referenced in function
_D3std5stdio4File17LockingTextWriter10__T3putTwZ3putMFNbNiNfwZv
CMain.obj : error LNK2019: unresolved external symbol _d_assert
referenced in function _D4main8__assertFiZv (void
main.__assert(int))
CMain.obj : error LNK2019: unresolved external symbol _d_unittest
referenced in function _D4main15__unittest_failFiZv (void
main.__unittest_fail(int))
CMain.obj : error LNK2019: unresolved external symbol
_D3std5stdio4File17LockingTextWriter6__dtorMFNeZv (@trusted void
std.stdio.File.LockingTextWriter.__dtor()) referenced in function
_D3std5stdio16__T7writelnTAyaZ7writelnFNfAyaZv (@safe void
std.stdio.writeln!(immutable(char)[]).writeln(immutable(char)[]))
CMain.obj : error LNK2019: unresolved external symbol
_d_arraybounds referenced in function _D4main7__arrayZ
x64\Debug DMD\CMain.exe : fatal error LNK1120: 23 unresolved
externals
So, something funky is going on. Any ideas?
