Re: Segfault in shared object when writeln

[Harpo via Digitalmars-d-learn]

Thanks! that was perfect.
-Harpo

Re: Segfault in shared object when writeln

[ed via Digitalmars-d-learn]

On Wednesday, 4 June 2014 at 04:46:59 UTC, ed wrote:

On Wednesday, 4 June 2014 at 03:49:25 UTC, Harpo wrote:
Hello I am having the following problem. I am trying to turn a 
program I have written into a shared object. I have ran into 
some problems however. When I use writeln instead of printf my 
program segfaults. I have edited the code to just the parts 
causing the problem.


=main.d the so

import std.stdio;
import core.stdc.stdio;

extern (C) void main(){
writeln("Does it work?");
printf("Works");
}

==main.c the main executable==

#include 
#include 
#include 

int main() {
 printf("+main()\n");

 void *lh = dlopen("THE PATH EDITED FOR MY SECURITY", 
RTLD_LAZY);

 if (!lh) {
   fprintf(stderr, "dlopen error: %s\n", dlerror());
   exit(1);
 }
 printf("libdll.so is loaded\n");

 void (*fn)() = dlsym(lh, "main");
 char *error = dlerror();
 if (error) {
   fprintf(stderr, "dlsym error: %s\n", error);
   exit(1);
 }
 printf("dll() function is found\n");
 (*fn)();

 printf("unloading libdll.so\n");
 dlclose(lh);

 printf("-main()\n");
 return 0;
}

The compile script===

dmd -c main.d -fPIC

dmd -oflibdll.so main.o -shared -defaultlib=libphobos2.so 
-L-rpath=/usr/lib/x86_64-linux-gnu -L-ldl -gc


gcc -c main.c
gcc -rdynamic main.o -o main -ldl

=
When I have just printf is works. When I have writeln it 
segfaults.


This fails

import std.stdio;

extern (C) void main(){
writeln("Does it work?");
}

This works

import core.stdc.stdio;

extern (C) void main(){
printf("Works");
}

===

Any one know whats up? Thanks!
-Harpo


I believe you need to initialise the D runtime in your D code 
before using Phobos or druntime itself in this manner. The 
printf call just wraps the C runtime but writeln requires the D 
runtime to be initialised.


Check out
http://dlang.org/phobos/core_runtime.html#.Runtime.initialize
http://dlang.org/phobos/core_runtime.html#.Runtime.terminate

Cheers,
ed



Cheers,
ed


I just remembered you can do this on the C side, which is easier 
to manage


http://dlang.org/phobos/core_runtime.html#.rt_init
http://dlang.org/phobos/core_runtime.html#.rt_term

Cheers,
ed

Re: Segfault in shared object when writeln

[ed via Digitalmars-d-learn]

On Wednesday, 4 June 2014 at 03:49:25 UTC, Harpo wrote:
Hello I am having the following problem. I am trying to turn a 
program I have written into a shared object. I have ran into 
some problems however. When I use writeln instead of printf my 
program segfaults. I have edited the code to just the parts 
causing the problem.


=main.d the so

import std.stdio;
import core.stdc.stdio;

extern (C) void main(){
writeln("Does it work?");
printf("Works");
}

==main.c the main executable==

#include 
#include 
#include 

int main() {
  printf("+main()\n");

  void *lh = dlopen("THE PATH EDITED FOR MY SECURITY", 
RTLD_LAZY);

  if (!lh) {
fprintf(stderr, "dlopen error: %s\n", dlerror());
exit(1);
  }
  printf("libdll.so is loaded\n");

  void (*fn)() = dlsym(lh, "main");
  char *error = dlerror();
  if (error) {
fprintf(stderr, "dlsym error: %s\n", error);
exit(1);
  }
  printf("dll() function is found\n");
  (*fn)();

  printf("unloading libdll.so\n");
  dlclose(lh);

  printf("-main()\n");
  return 0;
}

The compile script===

dmd -c main.d -fPIC

dmd -oflibdll.so main.o -shared -defaultlib=libphobos2.so 
-L-rpath=/usr/lib/x86_64-linux-gnu -L-ldl -gc


gcc -c main.c
gcc -rdynamic main.o -o main -ldl

=
When I have just printf is works. When I have writeln it 
segfaults.


This fails

import std.stdio;

extern (C) void main(){
writeln("Does it work?");
}

This works

import core.stdc.stdio;

extern (C) void main(){
printf("Works");
}

===

Any one know whats up? Thanks!
-Harpo


I believe you need to initialise the D runtime in your D code 
before using Phobos or druntime itself in this manner. The printf 
call just wraps the C runtime but writeln requires the D runtime 
to be initialised.


Check out
http://dlang.org/phobos/core_runtime.html#.Runtime.initialize
http://dlang.org/phobos/core_runtime.html#.Runtime.terminate

Cheers,
ed



Cheers,
ed

Segfault in shared object when writeln

[Harpo via Digitalmars-d-learn]

Hello I am having the following problem. I am trying to turn a 
program I have written into a shared object. I have ran into some 
problems however. When I use writeln instead of printf my program 
segfaults. I have edited the code to just the parts causing the 
problem.


=main.d the so

import std.stdio;
import core.stdc.stdio;

extern (C) void main(){
writeln("Does it work?");
printf("Works");
}

==main.c the main executable==

#include 
#include 
#include 

int main() {
  printf("+main()\n");

  void *lh = dlopen("THE PATH EDITED FOR MY SECURITY", RTLD_LAZY);
  if (!lh) {
fprintf(stderr, "dlopen error: %s\n", dlerror());
exit(1);
  }
  printf("libdll.so is loaded\n");

  void (*fn)() = dlsym(lh, "main");
  char *error = dlerror();
  if (error) {
fprintf(stderr, "dlsym error: %s\n", error);
exit(1);
  }
  printf("dll() function is found\n");
  (*fn)();

  printf("unloading libdll.so\n");
  dlclose(lh);

  printf("-main()\n");
  return 0;
}

The compile script===

dmd -c main.d -fPIC

dmd -oflibdll.so main.o -shared -defaultlib=libphobos2.so 
-L-rpath=/usr/lib/x86_64-linux-gnu -L-ldl -gc


gcc -c main.c
gcc -rdynamic main.o -o main -ldl

=
When I have just printf is works. When I have writeln it 
segfaults.


This fails

import std.stdio;

extern (C) void main(){
writeln("Does it work?");
}

This works

import core.stdc.stdio;

extern (C) void main(){
printf("Works");
}

===

Any one know whats up? Thanks!
-Harpo