WProgram.h error: functions that differ only in their return type cannot be overloaded

[SimonSapin]

I’m preparing a pull request that uses https://github.com/PaulStoffregen/cores/ as a submodule rather than having a copy of it in this repository, and also running rust-bindgen when building the teensy-sys crate. Bindgen (or presumably libclang, which bindgen uses) fails with this error:

cores/teensy3/WProgram.h:53:9: error: functions that differ only in their return type cannot be overloaded
/usr/include/stdlib.h:298:17: note: previous declaration is here

The first source line referenced is:

// WMath prototypes
int32_t random(void);

The second (on my system, Archlinux x86_64) is:

/* Return a random long integer between 0 and RAND_MAX inclusive.  */
extern long int random (void) __THROW;

I believe that long int is the same as int32_t on thumbv7em-none-eabi, but libclang seem to consider them different anyway. Changing the first line to use long works around the problem, but I’d rather not maintain a fork of the repository. So for now I’m adding a hack in teensy-sys/build.rs that does this replacement into a temporary file.

This issue is about getting rid of this hack eventually. Sending a pull request upstream would be best, but for now I don’t know if simply changing uint32_t to long is appropriate.

CC PaulStoffregen/cores#187, PaulStoffregen/cores#83

[danwalmsley]

I have also just come across this issue when using the Clang compiler.