PRX builds using psp-cmake fail with _exit linker error and missing exports.exp

[santiago046]

When compiling any PRX project using psp-cmake, the build fails with a missing _exit symbol during linking. In addition, if the .exp file is not manually copied to the build directory, the generation of exports.c fails due to Could not open file exports.exp.

Steps to Reproduce

1. Clone pspsdk

git clone https://github.com/pspdev/pspsdk/

2. Create any minimal PRX project (e.g., in pspsdk/src/samples/prx/testprx) with the following CMakeLists.txt:

cmake_minimum_required(VERSION 3.11)

project(testprx C)

add_prx_module(${PROJECT_NAME}
    main.c
    exports.exp
)

install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}.prx DESTINATION .)

3. Run:

cd pspsdk/src/samples/prx/testprx
psp-cmake -Bbuild
cmake --build build

Output

[ 25%] Generating exports.c from exports.exp for target testprx
Could not open file exports.exp
[ 50%] Building C object CMakeFiles/testprx.dir/main.c.obj
[ 75%] Building C object CMakeFiles/testprx.dir/exports.c.obj
[100%] Linking C executable testprx
/root/pspdev/bin/../lib/gcc/psp/.../ld: warning: cannot find entry symbol module_start; defaulting to 00000000
/root/pspdev/bin/../lib/gcc/psp/15.1.1/../../../../psp/bin/ld: /root/pspdev/psp/lib/libc.a(libc_a-abort.o): in function `abort':
/home/runner/work/pspdev/pspdev/build/psptoolchain/build/psptoolchain-allegrex/build/newlib/build-psp/psp/newlib/../../../newlib/libc/stdlib/abort.c:59:(.text+0x10): undefined reference to `_exit'
collect2: error: ld returned 1 exit status

Note: copying exports.exp to the build directory, or specifing the absolute path to it, fixes Could not open file exports.exp.

[sharkwouter]

Since the PR is merged now, this will be resolved by using the develop build. There will be a new automated release on the first of August, then it will be in the latest version.

[sharkwouter]

We did a release a couple of days ago. Can you make sure it is fixed with the latest release?

[santiago046]

I am still trying to figure out what is causing the undefined reference to _exit because my pull request only fixed the exports.exp file being not found. However, I found out linking pspkernel library fixes it, which is strange because build.mak only links that if USE_KERNEL_LIBS is set to true/1.

[crozone]

@santiago046 I have the same issue with _exit:

/__w/pspdev/pspdev/build/psptoolchain/build/psptoolchain-allegrex/build/newlib/build-psp/psp/newlib/../../../newlib/libc/stdlib/abort.c:59:(.text+0x10): undefined reference to `_exit'

After bisecting my changes, I found it occurs whenever I use any sort of print function, like:

• pspDebugScreenPrintf()
• fprintf()
• printf()

However, the kernel functions for printing like pspDebugScreenKprintf() work just fine. So it's definitely something weird with not using kernel libraries - or something like that, I'm a bit out of my depth on this one.

[santiago046]

I made a mistake. For a PRX that uses main() function like testprx, the correct approach is:

add_executable(${PROJECT_NAME} main.c)
create_pbp_file(
  TARGET ${PROJECT_NAME}
  BUILD_PRX ON
)

add_prx_module is meant for PRX modules like src/samples/prx/image_display. I apologize for this confusion, I'm still learning how this works.

---

After bisecting my changes, I found it occurs whenever I use any sort of print function

@crozone Once I removed vsnprintf and snprintf calls, my code compiled without any linker errors.

So it seems the problem isn’t with the CMake build system, but rather with using printf-family functions. It might be related to #56