Compiler Option: -print - FreeBASIC Wiki Manual | FBWiki

The -print option can be used to query the compiler for certain information which may be useful especially for build scripts. It does not prevent compilation of input files given besides the -print option, but the compiler also can be invoked with only a -print option and no input files, in which case it will not compile anything but only respond to the -print option.

Currently, the following -print options are recognized:

option	effect
fblibdir	Prints the compiler's lib/ path
host	Prints the host system on which fbc is running
target	Prints the target system for which fbc is compiling (can be affected by the -target option)
x	Prints the file name of the output executable or library that fbc will or would generate (named after the -x option), depending on other command line options
sha-1	Prints the source code revision sha-1 used to build the compiler if defined at fbc build time, or an empty string if it was not defined
fork-id	Prints the custom defined project fork identifier name if defined at fbc build time, or an empty string if it was not defined

A makefile could use target := $(shell $(FBC) -print target) to find out the compilation target, which would even work when cross-compiling, with FBC set to something like fbc -target foo.

fbc -print x alone will print out the executable file extension for the target system.
fbc -print x -dll on the other hand will print out the dynamic library file name format.
fbc -print x -m foo will print out the executable file name that would be used when compiling a module called foo.bas.
fbc 1.bas 2.bas -lib -print x will compile 1.bas and 2.bas into a library, whose file name will be displayed.