Compiler Option: -target

FreeBASIC

previous page next page

Set the target platform for cross compilation

Syntax

-target < platform >

Parameters

platform

The target platform. Recognized values:

dos
win32
win64
xbox
<os>-<arch>

<os> can be one of:

linux
cygwin
darwin
freebsd
netbsd
openbsd

<arch> can be one of:

x86
x86_64
arm
aarch64

Examples:

linux-x86
linux-x86_64
linux-arm
linux-aarch64
freebsd-x86
freebsd-x86_64
...

For backwards compatibility, the following values are recognized. They will select the corresponding operating system, together with the compiler's default architecture (same as the host), because these values do not specify an architecture explicitly.
- linux
- cygwin
- darwin
- freebsd
- netbsd
- openbsd
The Normal fbc (e.g. FB-linux release) additionally recognizes GNU triplets, for example:
- i686-w64-mingw32
- x86_64-w64-mingw32
- i686-pc-linux-gnu
- arm-linux-gnueabihf
- ...

Description

The -target compiler option can be used to create an executable for a platform which is different from the host on which the source code is being compiled and linked. Appropriate libraries and cross compilation tools (assembler, linker) must be installed for cross compilation to work (also see FB and cross-compiling).

If -target <platform> is given, the compiler will compile programs more or less as if they were compiled on the given platform. This affects which __FB_*__ operating-system-specific symbol will be pre-defined, the default calling convention, the object and executable file format (e.g. ELF/COFF), the available runtime libraries and functions, etc.

With a standalone FB setup such as the FB-dos or FB-win32 releases:

Specifying -target <platform> causes the compiler to use the compiler tools in the bin/<platform>/ directory, and target-specific libraries in the lib/<platform>/ directory. For example, -target win32 causes the compiler to compile for Win32 and use tools from bin/win32/ and libraries from lib/win32/.
It is unnecessary (but safe) to specify a -target option that matches the host (for example -target win32 on win32). It does not make a difference to the compilation process.
If -target is not specified, the compiler defaults to compiling for the native system. It will then use the compiler tools and libraries from the bin/ and lib/ directories corresponding to the native system.

With a normal FB setup such as the FB-linux release:

Specifying -target <platform> causes the compiler to prefix the <platform>- string to the executable names of binutils and gcc. For example, specifying -target i686-w64-mingw32 causes the compiler to invoke i686-w64-mingw32-ld instead of ld (same for other tools besides the linker). This allows fbc to integrate with binutils/gcc cross-compiler toolchains and matches how cross-compiling tools are typically installed on Linux distributions.
Note that specifying something like -target win32 does not usually make sense here. It causes the compiler to try to use win32-ld which usually does not exist, because binutils/gcc toolchains for cross-compilation to Windows typically have names such as i686-pc-mingw32, not just win32. Thus, it is necessary to specify something like -target i686-pc-mingw32 instead of -target win32.
For backwards compatibility, if the given platform string describes the host and is an FB target name (the values accepted by the -target option with a standalone FB setup) instead of a GNU triplet, then the -target option will be ignored, and the <platform>- string will not be prefixed to compiler tools. For example, this allows -target linux to work with the FB-linux release. It will be ignored instead of causing the compiler to try to use linux-ld instead of ld.
If -target is not specified, the compiler defaults to compiling for the native system, and it will invoke binutils/gcc without a target-specific prefix. This allows fbc to integrate with usual Linux (and similar) systems where binutils/gcc for native compilation are installed without any target-specific prefix.
Libraries besides FB's own runtime libraries are located by running gcc -print-file-name=... (or <platform>-gcc -print-file-name=...). This allows fbc to use the system and gcc libraries installed on Linux and similar systems without knowing the exact installation directories.