ARM Software Development Toolkit Reference Guide 4.4. The embedded C library

4.4. The embedded C library

The ARM embedded C library addresses problems caused by linking the standard ANSI C library into an embedded system. The ARM embedded C library is a subset of the full ANSI C library that addresses the following issues:

The standard ANSI C library relies on underlying Angel SWIs for its operation. Unless your embedded system supports these SWIs in its SWI handler, the C library will not work correctly.
For the standard ANSI C library to execute, the memory system must be configured in the way expected by the C library. This may not be easy to support in your embedded system.
There is a minimum overhead of about 3KB when the standard ANSI C library is included. The embedded C library has no overhead.
The ANSI C library is non-reentrant. This may cause problems in embedded systems.

Refer to Example 3: Using the embedded C library of the ARM Software Development Toolkit User Guide for an example of how to use the embedded C library.

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