GPS: Including C headers from paths which are not configured in Source_Dirs

GPS: Including C headers from paths which are not configured in Source_Dirs

[Rego, P.]

In a project I have Ada and C files, for example, ohmy.adb, and bla.c and bla.h, and some other files which are not listed in this Ada main project. For simplicity,

project Test is
	for Languages use ("Ada", "C");
	for Source_Dirs use (".");
	for Main use ("ohmy.adb");
end Test;

In bla.c I have an include 
#include "tools/mytool.h"

But directory 'tools' is not configured in Source_Dirs, so it does not find mytool.h. How can I configure GPS to understand this type of include "tools/mytool.h" (instead of including 'tools' in Source_Dirs and including the file using #include "mytool.h")?

Thanks.

Re: GPS: Including C headers from paths which are not configured in Source_Dirs

[Simon Wright]

"Rego, P." <pvrego@gmail.com> writes:

> project Test is
> 	for Languages use ("Ada", "C");
> 	for Source_Dirs use (".");
> 	for Main use ("ohmy.adb");
> end Test;
>
> In bla.c I have an include 
> #include "tools/mytool.h"
>
> But directory 'tools' is not configured in Source_Dirs, so it does not
> find mytool.h. How can I configure GPS to understand this type of
> include "tools/mytool.h" (instead of including 'tools' in Source_Dirs
> and including the file using #include "mytool.h")?

   package Compiler is
      for Switches ("C") use ("-I/your/include/dir");
   end Compiler;

But why are you using #include "tools/mytool.h" rather than #include
<tools/mytools.h>? (I've never understood why VxWorks uses this style).

Re: GPS: Including C headers from paths which are not configured in Source_Dirs

[Rego, P.]

On Thursday, October 8, 2015 at 12:29:32 PM UTC-3, Simon Wright wrote:
>    package Compiler is
>       for Switches ("C") use ("-I/your/include/dir");
>    end Compiler;

It did not work, maybe I did wrong. I built a test code to analyze better.

--test.gpr
project Test is 
   for Languages use ("Ada", "C"); 
   for Source_Dirs use ("."); 
   for Main use ("ohmy.adb"); 
	
   package Compiler is 
      for Switches ("C") use ("-Ioutsiders"); 
   end Compiler; 
   
end Test; 

--ohmy.adb
procedure Ohmy is
   procedure Put_Ohmy;
   pragma Import (C, Put_Ohmy, "putOhmy");
begin
   Put_Ohmy;
end Ohmy;

--bla.h
void putOhmy(void);

--bla.c
#include <bla.h>
#include "common/bla_other.h"

void putOhmy (void) {
    putOhmyOther();
}

--outsiders/common/bla_other.h
void putOhmyOther();

--outsiders/common/bla_other.c
#include <bla_other.h>
#include <stdio.h>

void putOhmyOther(){
    printf("Ohmy");
}

In this case, the built returns the error message:
> gprbuild -d -Ptest.gpr ohmy.adb
> gcc ohmy.o -o ohmy.exe
> libtest.a(bla.o):bla.c:(.text+0x7): undefined reference to `putOhmyOther'
> collect2.exe: error: ld returned 1 exit status
> gprbuild: link of ohmy.adb failed
> [2015-10-08 13:38:54] process exited with status 4, 100% (2/2), elapsed time: 03.94s

Realize that the folder 'outsiders' is included in project, so (I guess) its subfolders should be accessible by an include like '#include "common/bla_other.h"' (?) So what did I do wrong?

Thanks.

> 
> But why are you using #include "tools/mytool.h" rather than #include
> <tools/mytools.h>? (I've never understood why VxWorks uses this style).

Actually I don't know. It's a (big) legacy code, so I'd rather not changing this (if possible).

Re: GPS: Including C headers from paths which are not configured in Source_Dirs

[Qun-Ying]

Rego, P. wrote:
> On Thursday, October 8, 2015 at 12:29:32 PM UTC-3, Simon Wright wrote:
>>     package Compiler is
>>        for Switches ("C") use ("-I/your/include/dir");
>>     end Compiler;
>
> It did not work, maybe I did wrong. I built a test code to analyze better.
>
> --test.gpr
> project Test is
>     for Languages use ("Ada", "C");
>     for Source_Dirs use (".");
>     for Main use ("ohmy.adb");
> 	
>     package Compiler is
>        for Switches ("C") use ("-Ioutsiders");
>     end Compiler;
>
> end Test;
>
> --ohmy.adb
> procedure Ohmy is
>     procedure Put_Ohmy;
>     pragma Import (C, Put_Ohmy, "putOhmy");
> begin
>     Put_Ohmy;
> end Ohmy;
>
> --bla.h
> void putOhmy(void);
>
> --bla.c
> #include <bla.h>
> #include "common/bla_other.h"
>
> void putOhmy (void) {
>      putOhmyOther();
> }
>
> --outsiders/common/bla_other.h
> void putOhmyOther();
>
> --outsiders/common/bla_other.c
> #include <bla_other.h>
> #include <stdio.h>
>
> void putOhmyOther(){
>      printf("Ohmy");
> }
>
> In this case, the built returns the error message:
>> gprbuild -d -Ptest.gpr ohmy.adb
>> gcc ohmy.o -o ohmy.exe
>> libtest.a(bla.o):bla.c:(.text+0x7): undefined reference to `putOhmyOther'
>> collect2.exe: error: ld returned 1 exit status
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Your program compile fine, it include your header file without problem, 
but failed on linking.

As putOhmyOther is defined in common/bla_other.c, which is not compiled 
in your project.

>> gprbuild: link of ohmy.adb failed
>> [2015-10-08 13:38:54] process exited with status 4, 100% (2/2), elapsed time: 03.94s
>
> Realize that the folder 'outsiders' is included in project, so (I guess)
 > its subfolders should be accessible by an include like
 > '#include "common/bla_other.h"' (?) So what did I do wrong?

If you are linking with 3rd party C lib, not only do you need to include 
the header file, you also need to link with its lib.

Re: GPS: Including C headers from paths which are not configured in Source_Dirs

[Simon Wright]

"Rego, P." <pvrego@gmail.com> writes:

> On Thursday, October 8, 2015 at 12:29:32 PM UTC-3, Simon Wright wrote:
>>    package Compiler is
>>       for Switches ("C") use ("-I/your/include/dir");
>>    end Compiler;
>
> It did not work, maybe I did wrong. I built a test code to analyze better.
>
> --test.gpr
> project Test is 
>    for Languages use ("Ada", "C"); 
>    for Source_Dirs use ("."); 
>    for Main use ("ohmy.adb"); 
> 	
>    package Compiler is 
>       for Switches ("C") use ("-Ioutsiders"); 
>    end Compiler; 
>    
> end Test; 
>
> --ohmy.adb
> procedure Ohmy is
>    procedure Put_Ohmy;
>    pragma Import (C, Put_Ohmy, "putOhmy");
> begin
>    Put_Ohmy;
> end Ohmy;
>
> --bla.h
> void putOhmy(void);
>
> --bla.c
> #include <bla.h>
> #include "common/bla_other.h"
>
> void putOhmy (void) {
>     putOhmyOther();
> }

This clearly worked as intended, because bla.c got compiled.

> --outsiders/common/bla_other.h
> void putOhmyOther();
>
> --outsiders/common/bla_other.c
> #include <bla_other.h>
> #include <stdio.h>
>
> void putOhmyOther(){
>     printf("Ohmy");
> }

But ..

> In this case, the built returns the error message:
>> gprbuild -d -Ptest.gpr ohmy.adb
>> gcc ohmy.o -o ohmy.exe
>> libtest.a(bla.o):bla.c:(.text+0x7): undefined reference to `putOhmyOther'
>> collect2.exe: error: ld returned 1 exit status
>> gprbuild: link of ohmy.adb failed
>> [2015-10-08 13:38:54] process exited with status 4, 100% (2/2),
>> elapsed time: 03.94s

This is telling you that outsiders/common/bla_other.o never got included
in the link (probably never got compiled, either).

I take it that the outsiders directory corresponds to an
externally-built C library in your real application? Perhaps you could
represent it as a GPR of its own?

library project Outsiders is
   for Library_Name use "outsiders";
   for Library_Kind use "static";
   for Library_Dir use project'Project_Dir & "src";
   for Source_Dirs use project'Project_Dir & "include";
   for Externally_Built use "true";
end Outsiders;

and then your test.gpr might say

with Outsiders;
project Test is
   for Languages use ("Ada", "C");
   for Source_Dirs use (".");
   for Main use ("ohmy.adb");

   package Compiler is
      for Switches ("C") use ("-I" & Outsiders'Source_Dirs);
   end Compiler;
end Test;