DYLIB files generally don't need to be opened because of the nature of how they're used. However, you should be able to open one with Apple's Xcode, either through a menu or by just dragging the DYLIB file directly into the program.
Short answerNo, in Big Sur it's not safe to delete them (from the screenshot in your question, I see you are on macOS 11 Big Sur).
dylib is short for DYnamically linked LIBrary They are analogous to a windows *. dll file. They contain generic, unmodifiable code intended to be reused by many applications. Follow this answer to receive notifications.
.dylib stands for dynamic library. A Static library (.a) A Static library (. a) is a pack of compiled classes, functions which can be used together with iOS app development project. It is a compiled binary or fat file and can be shared between projects.
The Mach-O object file format used by Mac OS X for executables and libraries distinguishes between shared libraries and dynamically loaded modules. Use otool -hv some_file
to see the filetype of some_file
.
Mach-O shared libraries have the file type MH_DYLIB
and carry the extension .dylib. They can be linked against with the usual static linker flags, e.g. -lfoo
for libfoo.dylib. They can be created by passing the -dynamiclib
flag to the compiler. (-fPIC
is the default and needn't be specified.)
Loadable modules are called "bundles" in Mach-O speak. They have the file type MH_BUNDLE
. They can carry any extension; the extension .bundle
is recommended by Apple, but most ported software uses .so
for the sake of compatibility. Typically, you'll use bundles for plug-ins that extend an application; in such situations, the bundle will link against the application binary to gain access to the application’s exported API. They can be created by passing the -bundle
flag to the compiler.
Both dylibs and bundles can be dynamically loaded using the dl
APIs (e.g. dlopen
, dlclose
). It is not possible to link against bundles as if they were shared libraries. However, it is possible that a bundle is linked against real shared libraries; those will be loaded automatically when the bundle is loaded.
Historically, the differences were more significant. In Mac OS X 10.0, there was no way to dynamically load libraries. A set of dyld APIs (e.g. NSCreateObjectFileImageFromFile
, NSLinkModule
) were introduced with 10.1 to load and unload bundles, but they didn't work for dylibs. A dlopen
compatibility library that worked with bundles was added in 10.3; in 10.4, dlopen
was rewritten to be a native part of dyld and added support for loading (but not unloading) dylibs. Finally, 10.5 added support for using dlclose
with dylibs and deprecated the dyld APIs.
On ELF systems like Linux, both use the same file format; any piece of shared code can be used as a library and for dynamic loading.
Finally, be aware that in Mac OS X, "bundle" can also refer to directories with a standardized structure that holds executable code and the resources used by that code. There is some conceptual overlap (particularly with "loadable bundles" like plugins, which generally contain executable code in the form of a Mach-O bundle), but they shouldn't be confused with Mach-O bundles discussed above.
Additional references:
The file .so is not a UNIX file extension for shared library.
It just happens to be a common one.
Check line 3b at ArnaudRecipes sharedlib page
Basically .dylib is the mac file extension used to indicate a shared lib.
The difference between .dylib and .so on mac os x is how they are compiled. For .so files you use -shared and for .dylib you use -dynamiclib. Both .so and .dylib are interchangeable as dynamic library files and either have a type as DYLIB or BUNDLE. Heres the readout for different files showing this.
libtriangle.dylib:
Mach header
magic cputype cpusubtype caps filetype ncmds sizeofcmds flags
MH_MAGIC_64 X86_64 ALL 0x00 DYLIB 17 1368 NOUNDEFS DYLDLINK TWOLEVEL NO_REEXPORTED_DYLIBS
libtriangle.so:
Mach header
magic cputype cpusubtype caps filetype ncmds sizeofcmds flags
MH_MAGIC_64 X86_64 ALL 0x00 DYLIB 17 1256 NOUNDEFS DYLDLINK TWOLEVEL NO_REEXPORTED_DYLIBS
triangle.so:
Mach header
magic cputype cpusubtype caps filetype ncmds sizeofcmds flags
MH_MAGIC_64 X86_64 ALL 0x00 BUNDLE 16 1696 NOUNDEFS DYLDLINK TWOLEVEL
The reason the two are equivalent on Mac OS X is for backwards compatibility with other UNIX OS programs that compile to the .so file type.
Compilation notes: whether you compile a .so file or a .dylib file you need to insert the correct path into the dynamic library during the linking step. You do this by adding -install_name and the file path to the linking command. If you dont do this you will run into the problem seen in this post: Mac Dynamic Library Craziness (May be Fortran Only).
Just an observation I just made while building naive code on OSX with cmake:
cmake ... -DBUILD_SHARED_LIBS=OFF ...
creates .so files
while
cmake ... -DBUILD_SHARED_LIBS=ON ...
creates .dynlib files.
Perhaps this helps anyone.
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