#645 _sbrk_r with incr == 0 should be valid

[Paul Szego]

In os/various/syscalls.c, in function _sbrk_r: if called with 'incr' of zero fails due to this line:

chDbgCheck(incr > 0);

According to some definitions I've found, if called with incr == 0 it should return the current end of the heap, and not fail. And i'm seeing it get called that way when linking with g++.

To get my system working I hacked this into the function, but it's not a general solution (the return value isn't even accurate, it's just something to stop the runtime errors):

  extern caddr_t __heap_base__;

  if ( incr == 0 ) {
      return __heap_base__;
  }

Is there a proper way to do this?

Some linker settings that may be pertinent (not the complete command line):

arm-none-eabi-g++ -nostartfiles -nodefaultlibs -nostdlib --specs=nano.specs --specs=nosys.specs -lstdc++ -lsupc++ -lm -lc -lgcc -lnosys

[Giovanni Di Sirio]

Hi,

Just the chDbgCheck() needs a change, chCoreAlloc() behaves as expected. I committed the change to the check.

Giovanni