libunwind

libunwind is a portable and efficient C API for determining the current call chain of ELF program threads of execution and for resuming execution at any point in that call chain. The API supports both local (same process) and remote (other process) operation.

The API is useful in a number of applications, including but not limited to the following.

• program introspection Either for error messages showing a back trace of the call chain leading to a problem or for performance monitoring and analysis.
• debugging Whether the debugging and analysis of the call chain of a remote program or the post-mortem analysis of a coredump.
• language runtime exception handling libunwind optionally provides an alternative implementation of the Itanium exception handling ABI used by many popular toolchains.
• alternative setjmp()/longjmp() libunwind optionally provides an alternative implementation of the setjmp()/longjmp() functionality of the C standard library.

Supported Systems

This library supports several architecture/operating-system combinations:

System	Architecture	Status
Linux	x86-64	✓
Linux	x86	✓
Linux	ARM	✓
Linux	AArch64	✓
Linux	Alpha	✓
Linux	PPC32	✓
Linux	PPC64	✓
Linux	PPC64LE	✓
Linux	s390x	✓
Linux	SuperH	✓
Linux	IA-64	✓
Linux	PA-RISC	Works well, but C library missing unwind-info
Linux	MIPS	✓
Linux	RISC-V	✓
Linux	LoongArch	64-bit only
HP-UX	IA-64	Mostly works, but known to have serious limitations
FreeBSD	x86-64	✓
FreeBSD	x86	✓
FreeBSD	AArch64	✓
FreeBSD	PPC32	✓
FreeBSD	PPC64	✓
FreeBSD	RISC-V	✓
QNX	Aarch64	✓
QNX	x86-64	✓
Solaris	x86-64	✓

General Build Instructions

In general, this library can be built and installed with the following commands:

$ autoreconf -i # Needed only for building from git. Depends on libtool.
$ ./configure --prefix=PREFIX
$ make
$ make install

where PREFIX is the installation prefix. By default, a prefix of /usr/local is used, such that libunwind.a is installed in /usr/local/lib and unwind.h is installed in /usr/local/include.

Regression Testing

After building the library, you can run a set of regression tests with:

$ make check

Performance Testing

This distribution includes a few simple performance tests which give some idea of the basic cost of various libunwind operations. After building the library, you can run these tests with the following commands:

$ cd tests
$ make perf

Contacting the Developers

Please raise issues and pull requests through the GitHub repository: https://github.com/libunwind/libunwind.