DYLD(3)

NAME
dyld - low level programatic interface to the dynamic link editor

SYNOPSIS

#include <mach-o/dyld.h>
unsigned long _dyld_present(void);

unsigned long _dyld_image_count(void);

struct mach_header *_dyld_get_image_header(
	unsigned long image_index);

unsigned long _dyld_get_image_vmaddr_slide(
	unsigned long image_index);

char *_dyld_get_image_name(
	unsigned long image_index);

void _dyld_lookup_and_bind(
	char *symbol_name,
	unsigned long *address,
	void **module);

void _dyld_lookup_and_bind_with_hint(
	char *symbol_name,
	const char *library_name_hint,
	unsigned long *address,
	void **module);

void _dyld_lookup_and_bind_fully(
	char *symbol_name,
	unsigned long *address,
	void **module);

enum bool _dyld_bind_fully_image_containing_address(
	unsigned long *address);

enum bool _dyld_image_containing_address(
	unsigned long address);

enum bool _dyld_get_image_header_containing_address(
	unsigned long address);

enum bool _dyld_launched_prebound(void);

enum bool _dyld_all_twolevel_modules_prebound(void);

int _dyld_func_lookup(
	char *dyld_func_name,
	unsigned long *address);

extern void _dyld_bind_objc_module(
	void *objc_module);

extern void _dyld_get_objc_module_sect_for_module(
	NSModule module,
	void **objc_module,
	unsigned long *size);

extern void _dyld_lookup_and_bind_objc(
	const char *symbol_name,
	unsigned long *address,
	void **module);

extern void _dyld_moninit(
	void (*monaddition)(char *lowpc, char *highpc));

extern void _dyld_register_func_for_add_image(
	void (*func)(struct mach_header *mh, unsigned long vmaddr_slide));

extern void _dyld_register_func_for_remove_image(
	void (*func)(struct mach_header *mh, unsigned long vmaddr_slide));

extern void _dyld_register_func_for_link_module(
	void (*func)(NSModule module));

DESCRIPTION
These routines are the low level programatic interface to the dynamic link editor.

_dyld_present returns non-zero if the dynamic linker is being used in the program and zero otherwise. If this returns zero this rest of these functions should not be called and most likely crash the program if called.

_dyld_image_count returns the current number of images mapped in by the dynamic link editor.

_dyld_get_image_header returns the mach header of the image indexed by image_index. If image_index is out of range NULL is returned.

_dyld_get_image_vmaddr_slide returns the virtural memory address slide amount of the image indexed by image_index. If image_index is out of range zero is returned.

_dyld_get_image_name returns the name of the image indexed by image_index. If image_index is out of range NULL is returned.

_dyld_lookup_and_bind looks up the symbol_name and binds it into the program. It indirectly returns the address and and a pointer to the module that defined the symbol.

_dyld_lookup_and_bind_with_hint is the same as _dyld_lookup_and_bind but the library_name_hint parameter provides a hint as to where to start the lookup in a prebound program. The library_name_hint parameter is matched up with the actual library install names with strstr(3).

_dyld_lookup_and_bind_fully looks up the symbol_name and binds it and all of its references into the program. It indirectly returns the address and and a pointer to the module that defined the symbol.

_dyld_bind_fully_image_containing_address fully binds the image containing the specified address. It returns TRUE if the address is contained in a loaded image and FALSE otherwise.

_dyld_image_containing_address It returns TRUE if the address is contained in an image dyld loaded and FALSE otherwise.

_dyld_get_image_header_containing_address It returns a pointer to the mach header of the image if the address is contained in an image dyld loaded and NULL otherwise.

_dyld_launched_prebound returns TRUE if the program was launched using the prebound state and FALSE otherwise.

returns TRUE if all the libraries currently in use by the program are being used as two-level namespace libraries, are prebound and have all their modules bound. Otherwise it returns FALSE.

_dyld_func_lookup is passed a name, dyld_func_name, of a dynamic link editor function and returns the address of the function indirectly. It returns non-zero if the function is found and zero otherwise.

_dyld_bind_objc_module is passed a pointer to something in an (__OBJC,__module) section and causes the module that is associated with that address to be bound.

_dyld_get_objc_module_sect_for_module is passed a module and sets a pointer to the (__OBJC,__module) section and its size for the specified module.

_dyld_lookup_and_bind_objc() is the same as _dyld_lookup_and_bind() but does not update the symbol pointers if the symbol is in a bound module. The reason for this is that an objc symbol like .objc_class_name_Object is never used by a symbol pointer. Since this is done a lot by the objc runtime and updating symbol pointers is not cheep it should not be done.

_dyld_moninit is called from the profiling runtime routine moninit(3) to cause the dyld loaded code to be profiled. It is passed a pointer to the the profiling runtime routine monaddtion(3) to be called after an image had been mapped in.

_dyld_register_func_for_add_image registers the specified function to be called when a new image is added (a bundle or a dynamic shared library) to the program. When this function is first registered it is called for once for each image that is currently part of the program.

_dyld_register_func_for_remove_image registers the specified function to be called when an image is removed (a bundle or a dynamic shared library) from the program. _dyld_register_func_for_link_module registers the specified function to be called when a module is bound into the program. When this function is first registered it is called for once for each module that is currently bound into the program.