zstd/lib

Zstandard library files

The lib directory contains several directories. Depending on target use case, it's enough to include only files from relevant directories.

API

Zstandard's stable API is exposed within zstd.h, at the root of lib directory.

Advanced API

Some additional API may be useful if you're looking into advanced features :

• common/error_public.h : transforms size_t function results into an enum, for precise error handling.
• ZSTD_STATIC_LINKING_ONLY : if you define this macro before including zstd.h, it will give access to advanced and experimental API. These APIs shall never be used with dynamic library ! They are not "stable", their definition may change in the future. Only static linking is allowed.

ZSTDMT API

To enable multithreaded compression within the library, invoke make lib-mt target. Prototypes are defined in header file compress/zstdmt_compress.h. When linking a program that uses ZSTDMT API against libzstd.a on a POSIX system, -pthread flag must be provided to the compiler and linker. Note : ZSTDMT prototypes can still be used with a library built without multithread support, but in this case, they will be single threaded only.

Modular build

Directory common/ is required in all circumstances. You can select to support compression only, by just adding files from the compress/ directory, In a similar way, you can build a decompressor-only library with the decompress/ directory.

Other optional functionalities provided are :

• dictBuilder/ : source files to create dictionaries. The API can be consulted in dictBuilder/zdict.h. This module also depends on common/ and compress/ .

• legacy/ : source code to decompress previous versions of zstd, starting from v0.1. This module also depends on common/ and decompress/ . Library compilation must include directive ZSTD_LEGACY_SUPPORT = 1 . The main API can be consulted in legacy/zstd_legacy.h. Advanced API from each version can be found in their relevant header file. For example, advanced API for version v0.4 is in legacy/zstd_v04.h .

Using MinGW+MSYS to create DLL

DLL can be created using MinGW+MSYS with the make libzstd command. This command creates dll\libzstd.dll and the import library dll\libzstd.lib. The import library is only required with Visual C++. The header file zstd.h and the dynamic library dll\libzstd.dll are required to compile a project using gcc/MinGW. The dynamic library has to be added to linking options. It means that if a project that uses ZSTD consists of a single test-dll.c file it should be linked with dll\libzstd.dll. For example:

    gcc $(CFLAGS) -Iinclude/ test-dll.c -o test-dll dll\libzstd.dll

The compiled executable will require ZSTD DLL which is available at dll\libzstd.dll.

Obsolete streaming API

Streaming is now provided within zstd.h. Older streaming API is still available within deprecated/zbuff.h. It will be removed in a future version. Consider migrating code towards newer streaming API in zstd.h.

Miscellaneous

The other files are not source code. There are :

• LICENSE : contains the BSD license text
• Makefile : script to compile or install zstd library (static and dynamic)
• libzstd.pc.in : for pkg-config (make install)
• README.md : this file