BSP Developer's Guide

8
Writing Portable C Code
8.1.5 Other Issues
Follow Strict ANSI Compilation
Compilation units should be compiled with strict ANSI protocols in effect. This
requires detailed prototype declarations. For the GNU compiler system, the
compiler flags should include the following:
-Wall -W -Wmissing-declarations -Wstrict-prototypes -Wmissing-prototypes
Remove Compiler Warnings
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Portable code must be as free of warnings as possible. Apply the strictest possible
code checking and fix all reported warning situations. Compilers identify
non-portable code issues well when doing error checking.
Avoid Use of Casts
Each and every cast represents a potential error. It is a common practice to use a
cast to fix warnings reported by the compiler. However, each instance must be
examined carefully to insure that a cast is the appropriate action. Often a warning
indicates an actual error in argument passing that must be corrected. Using a cast
overrides the compiler’s ability to detect an actual error in data usage that may
prove to be significant.
Avoid inline Keyword
The C inline keyword is to be avoided until the GNU and Diab compilers can
implement it in a consistent manner. The current ANSI Specification, C99, does call
for an inline keyword. However, at this time, neither compiler fully supports this
specification. Although each accepts the inline keyword, there are subtle but
significant differences in the implementation. An update to this document will be
issued when support for the inline keyword is available.
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