GCC for beginners


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This page is intended to be a collection of tips for those who are new to GCC on RISC OS, perhaps those who are used to Acorn C/C++. For a tutorial, see also the GCC tutorial.


See this question in the RISC OS C Programming FAQ.

Header file naming

On Unix, there's a given hierarchy of header files. So when you install the C library header files (equivalent to UnixLib) they go in /usr/include. So you get files like:


When you install other packages they slot into this structure. For example the GPIB driver library I've been using today lives in:


and if you install the Linux kernel headers you get things like:

/usr/include/linux/adfs_fs.h (the ADFS driver for Linux)

and so on.

The name inside the pointy brackets <> is effectively the path without /usr/include on the front. So

#include <sys/types.h>

refers to



#include <bits/types.h>

refers to


They're different files, and they have different pathnames (in fact, in glibc on Linux, sys/types.h has a #include <bits/types.h>). In the list above notice there are two time.h files - you'd refer to the first one as plain <time.h> and the second as <sys/time.h>

Of course it's slightly more complicated than that - /usr/include is a system-wide path so you need to be the machine administrator to add things to it. If I'm not administrator I might put some header files in some other directory (/home/theo/myincludes say) and use a -isystem to refer to them.

GCC and GCCSDK pages

GCC for RISC OS, GCC tutorial, GCC common switches, GCC for beginners, UnixLib, ELFLoader
GCCSDK and Unix porting
GCCSDK, GCCSDK Releases, GCCSDK Development, Using GCCSDK, Autobuilder Development and Packaging Cygwin setup, Accelerating autobuilder with apt-proxy, ChoX11, Developer help wanted

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