fix build with gcc 15 #249

ftapajos · 2025-05-01T16:18:15Z

gcc 15 uses c23 as default. paho.mqtt.c is written with c11

gcc 15 uses c23 as default

fpagliughi · 2025-05-02T18:54:35Z

c11? I would have guessed c89... with maybe a line or two of c99 thrown in. :-)

I'll get a few more recent versions of gcc set up to test and then get this in. (I seem to still have gcc 12 on most of my machines)

Just curious. Can you cut-and-paste the errors that gcc 15 is giving? It's probably worth trying to get the Paho C lib updated for this. If nothing else, push the standard definition into the CMake files for that lib.

fpagliughi · 2025-05-02T18:56:02Z

Oh, and thanks for reporting this!

ftapajos · 2025-05-05T12:13:59Z

@fpagliughi , The error is related to the fact that bool is now a C keyword

In file included from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTProtocolClient.h:25,
                   from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTProtocolClient.c:35:
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: error: 'bool' cannot be defined via 'typedef'
     31 | typedef unsigned int bool;
        |                      ^~~~
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: note: 'bool' is a keyword with '-std=c23' onwards
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:1: warning: useless type name in empty declaration
     31 | typedef unsigned int bool;
        | ^~~~~~~
  make[2]: *** [src/CMakeFiles/common_obj_static.dir/build.make:93: src/CMakeFiles/common_obj_static.dir/MQTTProtocolClient.c.o] Error 1
  make[2]: *** Waiting for unfinished jobs....
  In file included from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacketOut.h:23,
                   from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacketOut.c:30:
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: error: 'bool' cannot be defined via 'typedef'
     31 | typedef unsigned int bool;
        |                      ^~~~
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: note: 'bool' is a keyword with '-std=c23' onwards
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:1: warning: useless type name in empty declaration
     31 | typedef unsigned int bool;
        | ^~~~~~~
  make[2]: *** [src/CMakeFiles/common_obj_static.dir/build.make:149: src/CMakeFiles/common_obj_static.dir/MQTTPacketOut.c.o] Error 1
  In file included from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.c:28:
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: error: 'bool' cannot be defined via 'typedef'
     31 | typedef unsigned int bool;
        |                      ^~~~
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: note: 'bool' is a keyword with '-std=c23' onwards
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:1: warning: useless type name in empty declaration
     31 | typedef unsigned int bool;
        | ^~~~~~~
  make[2]: *** [src/CMakeFiles/common_obj_static.dir/build.make:135: src/CMakeFiles/common_obj_static.dir/MQTTPacket.c.o] Error 1
  In file included from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTProtocolClient.h:25,
                   from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTProtocolClient.c:35:
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: error: 'bool' cannot be defined via 'typedef'
     31 | typedef unsigned int bool;
        |                      ^~~~
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: note: 'bool' is a keyword with '-std=c23' onwards
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:1: warning: useless type name in empty declaration
     31 | typedef unsigned int bool;
        | ^~~~~~~
  In file included from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.c:28:
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: error: 'bool' cannot be defined via 'typedef'
     31 | typedef unsigned int bool;
        |                      ^~~~
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: note: 'bool' is a keyword with '-std=c23' onwards
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:1: warning: useless type name in empty declaration
     31 | typedef unsigned int bool;
        | ^~~~~~~
  make[2]: *** [src/CMakeFiles/common_ssl_obj_static.dir/build.make:93: src/CMakeFiles/common_ssl_obj_static.dir/MQTTProtocolClient.c.o] Error 1
  make[2]: *** Waiting for unfinished jobs....
  make[2]: *** [src/CMakeFiles/common_ssl_obj_static.dir/build.make:135: src/CMakeFiles/common_ssl_obj_static.dir/MQTTPacket.c.o] Error 1
  make[1]: *** [CMakeFiles/Makefile2:125: src/CMakeFiles/common_obj_static.dir/all] Error 2
  make[1]: *** Waiting for unfinished jobs....
  In file included from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacketOut.h:23,
                   from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacketOut.c:30:
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: error: 'bool' cannot be defined via 'typedef'
     31 | typedef unsigned int bool;
        |                      ^~~~
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: note: 'bool' is a keyword with '-std=c23' onwards
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:1: warning: useless type name in empty declaration
     31 | typedef unsigned int bool;
        | ^~~~~~~
  make[2]: *** [src/CMakeFiles/common_ssl_obj_static.dir/build.make:149: src/CMakeFiles/common_ssl_obj_static.dir/MQTTPacketOut.c.o] Error 1
  In file included from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/Log.c:27:
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: error: 'bool' cannot be defined via 'typedef'
     31 | typedef unsigned int bool;
        |                      ^~~~
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: note: 'bool' is a keyword with '-std=c23' onwards
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:1: warning: useless type name in empty declaration
     31 | typedef unsigned int bool;
        | ^~~~~~~
  In file included from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTProtocolClient.h:25,
                   from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPersistence.c:31:
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: error: 'bool' cannot be defined via 'typedef'
     31 | typedef unsigned int bool;
        |                      ^~~~
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: note: 'bool' is a keyword with '-std=c23' onwards
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:1: warning: useless type name in empty declaration
     31 | typedef unsigned int bool;
        | ^~~~~~~
  make[2]: *** [src/CMakeFiles/common_ssl_obj_static.dir/build.make:205: src/CMakeFiles/common_ssl_obj_static.dir/Log.c.o] Error 1
  make[2]: *** [src/CMakeFiles/common_ssl_obj_static.dir/build.make:219: src/CMakeFiles/common_ssl_obj_static.dir/MQTTPersistence.c.o] Error 1
  In file included from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTProtocolOut.h:26,
                   from /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTProtocolOut.c:38:
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: error: 'bool' cannot be defined via 'typedef'
     31 | typedef unsigned int bool;
        |                      ^~~~
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:22: note: 'bool' is a keyword with '-std=c23' onwards
  /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/paho-mqtt-sys-0.10.1/paho.mqtt.c/src/MQTTPacket.h:31:1: warning: useless type name in empty declaration
     31 | typedef unsigned int bool;
        | ^~~~~~~
  make[2]: *** [src/CMakeFiles/common_ssl_obj_static.dir/build.make:247: src/CMakeFiles/common_ssl_obj_static.dir/MQTTProtocolOut.c.o] Error 1
  make[1]: *** [CMakeFiles/Makefile2:221: src/CMakeFiles/common_ssl_obj_static.dir/all] Error 2
  make: *** [Makefile:156: all] Error 2

  thread 'main' panicked at /home/tapajos/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/cmake-0.1.54/src/lib.rs:1119:5:

  command did not execute successfully, got: exit status: 2

fpagliughi · 2025-05-06T18:43:14Z

Ok. There is already an issue on the Paho C repo about this:
eclipse-paho/paho.mqtt.c#1576

I do want to fix this in the C lib, but even if I put up a PR now, it could be a while before the next C release. So we can get this in to the Rust builder to keep us going.

otaxhu · 2025-05-08T04:36:22Z

I tried by myself to compile using CFLAGS=-std=c11 and it worked/compiled.

But I guess it's much better to support older compilers.

Please take a look at this PR in the C library, it's 1 month old and hasn't received any comments

eclipse-paho/paho.mqtt.c#1595

otaxhu · 2025-05-08T05:00:54Z

@fpagliughi I tested compiling with CFLAGS=-std=c89 and it did not compiled.

[ellided]/paho.mqtt.c/src/MQTTProtocolClient.h:60:1: error: C++ style comments are not allowed in ISO C90
     60 | //#define MQTTStrdup(src) MQTTStrncopy(malloc(strlen(src)+1), src, strlen(src)+1)
        | ^
[...more-similars...]

EDIT:
Tested with CFLAGS=-std=c99 and it worked, so c99 or c11 could do it

fpagliughi · 2025-05-08T16:17:29Z

Yeah, I think the proper solution is what the C library is targeting. At this point, the C library is going with C99, so we can use that.
eclipse-paho/paho.mqtt.c#1576 (comment)

fpagliughi · 2025-05-14T23:46:38Z

OK. I pushed the C version back to C99 to be keep with the version that the C library is claiming to track, then published a new -sys crate (v0.10.3) which should fix the latest version of this crate currently up on crates.io.

I also sent a PR to the C lib to fix the upstream library:
eclipse-paho/paho.mqtt.c#1597

Thanks again!

fix build with gcc 15

37edc0c

gcc 15 uses c23 as default

fpagliughi mentioned this pull request May 14, 2025

paho-mqtt fails due to C23 incompatibility of paho-mqtt-c on new compilers #251

Closed

fpagliughi merged commit 0a60494 into eclipse-paho:master May 14, 2025
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fix build with gcc 15 #249

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fix build with gcc 15 #249

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