Page 131 - Programming Microcontrollers in C

116 Chapter 2 Advanced C Topics

If one is found, the data stored in the original block are copied to the
new block and the proper space is allocated. The pointer returned in
this case will not be the same as that passed.

Miscellaneous Functions

C provides several sets of miscellaneous functions that are very
useful. As mentioned earlier, the input/output functions that are
prototyped in stdio.h are not parts of the language, but instead
are separate functions. The miscellaneous functions are prototyped
is several different header files. Many of these functions are macros,
and if they are, the macro definitions are contained in the header file.
Following is a list of several header files specified by the ANSI
Standard. With each header file is a list of functions or function pro­
totypes contained within these files. You should look to the
documentation for your compiler to get the detailed descriptions of
each of these files.
As mentioned earlier, these files are there, tested, work and are
probably as robust and reliable as any code written. They do what
they are supposed to, and they are free. It makes little sense to re­
write these programs just to satisfy an ego trip. I have seen shop
coding standards that did not allow the use of standard library files
because the programmers could not examine the source code. Such a
standard is absolutely silly. If you do not trust the compiler to pro­
vide safe, satisfactory library code, you should not trust the compiler
to generate any code. Therefore, you are using the wrong compiler.
Get a compiler that meets your standard.
Most embedded programs that employ microcontrollers do not
have standard connections to input/output devices. For example, there
is rarely a terminal or a keyboard attached to an embedded system.
More likely you would expect to find a numeric, or special, keypad
and an LCD special purpose output display. None of the standard i/o
programs can connect with such devices. In such cases, it will be
your responsibility as the programmer to write drivers to interface
with these devices. Also, you will rarely see disk files in your em­
bedded product. Therefore, you will rarely need to include the header
file stdio.h in a microcontroller program.