Embedded Linux System Design and Development

uClinux 375

10.7.4 Memory Limitations

uClinux does not provide a dynamic stack. Executables have a predefined

stack size set at compile time using

elf2flt. Programmers should avoid

huge allocations on the stack. Instead use the heap or if the requirement is

not dynamic, move it to the bss section.

C++ programs use

malloc even for built-in data-type declarations via the

new operator. Many C++ applications have had problems running on uClinux.

The lack of MMU and a wise

malloc results in an unsolvable memory

fragmentation issue, rendering the system useless. Hence C++ is not recom-

mended on an MMU-less system. Redesign any application that has to allocate

small chunks of

malloc or if possible write application-specific allocation

methods that will internally ...