-.TH DYLD 1 "January 15, 2005" "Apple Computer, Inc."
+.TH DYLD 1 "March 23, 2007" "Apple Inc."
.SH NAME
dyld \- the dynamic link editor
.SH SYNOPSIS
.br
DYLD_ROOT_PATH
.br
+DYLD_SHARED_REGION
+.br
DYLD_INSERT_LIBRARIES
.br
DYLD_FORCE_FLAT_NAMESPACE
.br
DYLD_BIND_AT_LAUNCH
.br
-DYLD_PREBIND_DEBUG
-.br
-DYLD_NEW_LOCAL_SHARED_REGIONS
+DYLD_NO_FIX_PREBINDING
.br
-DYLD_IGNORE_PREBINDING
+DYLD_DISABLE_DOFS
.br
DYLD_PRINT_APIS
.br
DYLD_PRINT_SEGMENTS
.br
DYLD_PRINT_STATISTICS
+.br
+DYLD_PRINT_DOFS
.SH DESCRIPTION
The dynamic linker uses the following environment variables.
They affect any program that uses the dynamic linker.
This is a colon separated list of directories. The dynamic linker will prepend each of
this directory paths to every image access until a file is found.
.TP
+.B DYLD_SHARED_REGION
+This can be "use" (the default), "avoid", or "private". Settting it to
+"avoid" tells dyld to not use the shared cache. All OS dylibs are loaded
+dynamically just like every other dylib. Setting it to "private" tells
+dyld to remove the shared region from the process address space and mmap()
+back in a private copy of the dyld shared cache in the shared region address
+range. This is only useful if the shared cache on disk has been updated
+and is different than the shared cache in use.
+.TP
.B DYLD_INSERT_LIBRARIES
This is a colon separated list of dynamic libraries to load before the ones
specified in the program. This lets you test new modules of existing dynamic
.TP
.B DYLD_BIND_AT_LAUNCH
When this is set, the dynamic linker binds all undefined symbols
-the program needs at launch time. This includes function symbols that can are normally lazily bound at the time of their first call.
-.TP
-.B DYLD_PREBIND_DEBUG
-When this is set, the dynamic linker prints diagnostics about
-launching prebound programs and libraries. This lets you determine why a
-program is not being launched prebound.
-You can view the recorded library time stamps with the
-.B \-Lv
-option to
-.IR otool (1).
-.TP
-.PP
-For secure programs that are UNIX set uid or set gid, the dynamic linker will
-not use the dyld environment variables for path searching and library insertion,
-unless the program is run as the real user. For secure programs, the dynamic
-linker clears out the value of the dyld path and insertion environment
-variables. This is so that if a program is
-.IR exec (2)'ed
-from a secure program too will not have it's libraries searched for, as well.
-For statically linked secure programs that
-.IR exec (2)
-other programs that might use the dynamic linker, they too should clear out the
-values of the dyld path and insertion environment variables.
-.TP
-.B DYLD_NEW_LOCAL_SHARED_REGIONS
-When set, the dynamic linker directs the system to provide a new set of shared
-regions as the repository for library load requests for dynamic libraries
-built with
-.SM MH_SPLIT_SEGS
-(split shared libraries).
-
-Split shared libraries reside in a defined contiguous region of address space
-in all dynamic linker runtime processes. This space is backed by named regions
-or sub-maps. These sub-maps are owned by the system and items which are to
-mapped into them must be mapped via the
-.IR load_shared_file (2)
-call. The use of
-sub-maps promotes a high degree of system resource sharing between the
-processes which incorporate and use them. However, some processes require
-either additional or different libraries to be loaded into the shared region.
-While there is some space available within the shared region for alternate and
-new shared libraries, it is inappropriate to use that area for temporary or
-private libraries. Setting the
-.SM DYLD_NEW_LOCAL_SHARED_REGIONS
-flag will cause
-all children of the current process to have their own set of sub-maps. In this
-way the libraries found in the children's submaps will not be caused to be
-present in the submaps shared by the rest of the system.
-
-.SM DYLD_NEW_LOCAL_SHARED_REGIONS
-should be set by anyone wishing to run
-non-standard or temporary split shared libraries by setting an explicit path to
-point to them. i.e. by using the DYLD_LIBRARY_PATH environment variable
-instead of changing the root by executing a
-.IR chroot (2)
-call.
+the program needs at launch time. This includes function symbols that can are normally
+lazily bound at the time of their first call.
.TP
.B DYLD_PRINT_STATISTICS
Right before the process's main() is called, dyld prints out information about how
dyld spent its time. Useful for analyzing launch performance.
.TP
-.B DYLD_IGNORE_PREBINDING { app | all }
-Valid values are "app", "all", and "" (empty). The variable is useful for testing
-how various mixes of prebound and unprebound libraries perform. When set to "all",
-all prebinding is ignored. That is, dyld fixes up any prebound images as if the prebinding
-in it was invalid. When set to "all", just the prebinding information in main
-executables is ignored. When set the nothing, the prebinding in split-seg libraries
-is used, by all other prebinding is ignored.
+.B DYLD_NO_FIX_PREBINDING
+Normally, dyld will trigger the dyld shared cache to be regenerated if it notices
+the cache is out of date while launching a process. If this environment variable
+is set, dyld will not trigger a cache rebuild. This is useful to set while installing
+a large set of OS dylibs, to ensure the cache is not regenerated until the install
+is complete.
+.TP
+.B DYLD_DISABLE_DOFS
+Causes dyld not register dtrace static probes with the kernel.
.TP
.B DYLD_PRINT_INITIALIZERS
Causes dyld to print out a line when running each initializers in every image. Initializers
.TP
.B DYLD_PRINT_SEGMENTS
Causes dyld to print out a line containing the name and address range of each mach-o segment
-that dyld maps in.
+that dyld maps. In addition it prints information about if the image was from the dyld
+shared cache.
.TP
.B DYLD_PRINT_BINDINGS
Causes dyld to print a line each time a symbolic name is bound.
-
-
+.TP
+.B DYLD_PRINT_DOFS
+Causes dyld to print out information about dtrace static probes registered with the kernel.
.SH "SEE ALSO"
libtool(1), ld(1), otool(1)
projects / apple / dyld.git / blobdiff