FreeBASIC uses several tools for compiling source code in addition to the fbc compiler. The exact tools used by fbc and how they are invoked depends on how fbc was configured, the host platform (where fbc is running), the target platform (where the produced executable will be run), and other options (like environment variables and command line options).

FreeBASIC (fbc) may have been configured in one of two ways: either as standalone or prefixed. The standalone version searches directories relative to where the executable is located. The prefixed version has a hardcoded path configured in to the compiler indicating where it expects to find additional tools and libraries. For more information on configuring FreeBASIC, see the INSTALL text file located in the src/compiler directory of the FreeBASIC sources.

You can check if your installed version of fbc is "standalone" or "prefixed" by invoking fbc with the -version command line option.

If fbc was configured as "standalone", it will search for files relative to where the fbc executable is located. fbc is at the "top" of the directory tree and searches sub-directories below it. The "top" directory (which defaults to the location where fbc is located) can be overridden with the -prefix command line option. "topdir" shown in the directories below represents the directory where the fbc executable is located, or the directory specified with the -prefix command line option (if it was given). "<target>" refers to the target platform having the same name as specified by the -target option.

If not cross compiling, fbc looks in these locations:

If cross compiling, fbc looks in the these locations:

If fbc was configured as "prefixed", it will search for files relative to the configured prefix (hardcoded in the fbc executable). "prefix" shown in the directories below represents the configured prefix, or the directory specified with the -prefix command line option (if it was given). "<target>" refers to the target platform having the same name as specified by the -target option.

If not cross compiling, fbc looks in these locations:

If cross compiling, fbc looks in the these locations:

If fbc is unable to locate a file, it may invoke gcc -print-file-name=<file> to query the location of the file. The following are files that may be located using gcc:

fbc will invoke additional tools (binary executables) as part of the compiling and linking process. The following is a list of tools (executables) that may be invoked by fbc depending on the host platform, target, or type of executable or library to be produced:

fbc will search for these tools in the following manner:

"<target>" refers to the target platform having the same name as specified by the -target option.