# System Wrapper Functions

> System heap and other necessary APIs are not always available in the given operating system. Consequently an application can use third-part memory allocation mechanisms. The eXtremeDB System Abstraction Layer (SAL) provides a set of platform independent functions to allow customization in these cases.

> The following APIs perform specialized functions:

> mco_sys_dll_load | Load an external module (dll, so or etc.) library
> mco_sys_dll_error | Explanation of an error if one happened during the load of an external module
> Wrappers for system dynamic memory management functions
> mco_sys_malloc | The wrapper for C function `malloc()`
> mco_sys_realloc | The wrapper for C function `realloc()`
> mco_sys_calloc | The wrapper for C function `calloc()`
> mco_sys_valloc | The wrapper for C function `valloc()`
> mco_sys_free | The wrapper for C function `free()`
> mco_sys_vfree | The wrapper for C function `vfree()`