Let us first start with some general language rules for how to provide maintainable and portable C code. One of the main objectives is to use the ANSI C and the POSIX.1 standard wherever possible in order to maximum portability. This means that we can not use (unfortunately!) neither objective C nor C++. However, we also want to support original Kernighan Ritchie C compilers and C++ compilers which brings in two important aspects in the coding style:
It is important that there are no reserved words used as variable names, function calls etc in our code. Some of the more common problem makes are listed below but see also Identifiers
As the world is not ideal, there are some traps that often show up when coding after these standards. This sections gives an overview of the more serious ones.
Actually, most system calls are to be avoided - they are very often supported via variuous libwww APIs, especially provided by the libwww utilities or core modules. Explicitly the following should not be used:
printfshouldn't be used to output debug messages, use the libwww HTTrace instead. Also, you may want to use the trace filters
strdupis not supported on many platforms. Use libwww dynamic strings instead
sleepput the whole application to sleep and it not very portable. Use libwww timers instead
memmoveis not supported on many any platforms or dump core
strncasecmp(use libwww's strcasecomp and strncasecomp)
realloc(use libwww's memory macros)
NULLif size is 0.
/* ... */
#elif. Basic cpp doesn't know it.
//for comments. This is not supported by ANSI C.
Remember that your code should compile without warnings under an ANSI C compiler such as gcc with all warnings enabled BUT this is not enough. The more native compilers you can use the better - gcc is not the only example of an ANSI compiler.