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digitalmars.D.learn - Undefined reference to "S_ISDIR" and "S_ISREG" when compiling with

reply rempas <rempas tutanota.com> writes:
I'm having the following code:

```d
import core.sys.posix.sys.stat;

int is_dir(const char* path) {
   stat_t s;
   if (stat(path, &s) == 0) {
     if (S_ISDIR(s.st_mode)) return 1;
     else return 0;
   } else return 2;
}

int is_regf(const char* path) {
   stat_t s;
   if (stat(path, &s) == 0) {
     if (S_ISREG(s.st_mode)) return 1;
     else return 0;
   } else return 2;
}

extern (C) void main() {
   is_dir("/lol");
   is_regf("/tmp");
}
```

When I try to compile this code using "ldc2" and "dmd", I'm 
getting the following message (the "format" is different between 
the compilers tho):

```
estd.o:test.d:function _D4test6is_dirFxPaZi: error: undefined 
reference to '_D4core3sys5posixQk4stat7S_ISDIRFNbNikZb'
testd.o:test.d:function _D4test7is_regfFxPaZi: error: undefined 
reference to '_D4core3sys5posixQk4stat7S_ISREGFNbNikZb'
```
If I open the file from the "stat" module (in my linux system 
it's in "/usr/include/dlang/ldc/core/sys/posix/sys/stat.d"), I 
will see that these functions do exists and the weird thing is 
that it will work if I don't compile using the "-betterC" option 
but it will not if I do. If I'm not mistaken, "core*" should work 
with "-betterC". Any ideas?
Jan 10 2022
parent reply Adam D Ruppe <destructionator gmail.com> writes:
On Monday, 10 January 2022 at 19:20:56 UTC, rempas wrote:

 If I'm not mistaken, "core*" should work with "-betterC". Any 
 ideas?


You are mistaken, -betterC's main mission is to exclude core.

Declarations that just bind to something externally will still 
work, since it doesn't matter if they're included or not, but 
this one, being a macro in the original C, is a mini-function in 
D, and thus needs to be linked in.
Jan 10 2022
parent reply rempas <rempas tutanota.com> writes:
On Monday, 10 January 2022 at 19:28:56 UTC, Adam D Ruppe wrote:

 You are mistaken, -betterC's main mission is to exclude core.

 Declarations that just bind to something externally will still 
 work, since it doesn't matter if they're included or not, but 
 this one, being a macro in the original C, is a mini-function 
 in D, and thus needs to be linked in.


Thanks! It needs to be linked with which library? In C it doesn't 
need to be linked with nothing extra than the system library that 
the C compilers already link (unless you pass "-nostdlib" of 
course).
Jan 10 2022
parent reply Adam D Ruppe <destructionator gmail.com> writes:
On Monday, 10 January 2022 at 19:33:36 UTC, rempas wrote:

 Thanks! It needs to be linked with which library?


That segment of druntime.

You can get dmd to do it for you by using the `-i -i=core.sys` 
flags (or maybe just the -i=core.sys thing im not sure i haven't 
actually tried).

Or just stop using -brokenD and find joy lol


 In C it doesn't need to be linked with nothing extra than the 
 system library that the C compilers already link (unless you 
 pass "-nostdlib" of course).


In C, that I_ISDIR is a macro in the header file so there's 
nothing to link, it all gets inlined by the preprocessor.
Jan 10 2022
parent reply rempas <rempas tutanota.com> writes:
On Monday, 10 January 2022 at 20:11:06 UTC, Adam D Ruppe wrote:

 On Monday, 10 January 2022 at 19:33:36 UTC, rempas wrote:

 Thanks! It needs to be linked with which library?


 That segment of druntime.

 You can get dmd to do it for you by using the `-i -i=core.sys` 
 flags (or maybe just the -i=core.sys thing im not sure i 
 haven't actually tried).

 Or just stop using -brokenD and find joy lol


 In C it doesn't need to be linked with nothing extra than the 
 system library that the C compilers already link (unless you 
 pass "-nostdlib" of course).


 In C, that I_ISDIR is a macro in the header file so there's 
 nothing to link, it all gets inlined by the preprocessor.


I see. Thanks! I will see what this function is supposed to do in 
the "stat.d" file or I'll write assembly and implement the system 
call be myself. Have a nice day my friend!
Jan 10 2022
next sibling parent rempas <rempas tutanota.com> writes:
On Monday, 10 January 2022 at 20:28:43 UTC, rempas wrote:

 I see. Thanks! I will see what this function is supposed to do 
 in the "stat.d" file or I'll write assembly and implement the 
 system call be myself. Have a nice day my friend!


When never mind, I just copy pasted the macros from "stat.h" and 
everything seems to be working fine
Jan 10 2022
prev sibling parent reply Adam D Ruppe <destructionator gmail.com> writes:
On Monday, 10 January 2022 at 20:28:43 UTC, rempas wrote:

 I'll write assembly and implement the system call be myself.


It's not a system call, it just a bitflag tester.
Jan 10 2022
parent rempas <rempas tutanota.com> writes:
On Monday, 10 January 2022 at 21:17:22 UTC, Adam D Ruppe wrote:

 It's not a system call, it just a bitflag tester.


I wasn't talking about the flag actually but for the "stat" 
system call
Jan 13 2022