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DL_ITERATE_PHDR(3)	     Library Functions Manual	      DL_ITERATE_PHDR(3)

NAME
     dl_iterate_phdr -- iterate over program headers

LIBRARY
     For  the  dynamically  linked  binaries,  the  service  is  provided by ld-
     elf.so.1(1) dynamic linker.  Statically linked programs use an  implementa-
     tion of dl_iterate_phdr() from libc.

SYNOPSIS
     #include <link.h>

     int
     dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *),
	 void *data);

DESCRIPTION
     The  dl_iterate_phdr() function iterates over all ELF objects loaded into a
     process's address space, calling callback for each object, passing  it  in-
     formation	about  the  object's program headers and the data argument.  The
     iteration is aborted when all objects are passed, or when the next callback
     call returns non-zero value.  The information about the program headers  is
     passed in a structure that is defined as:

     struct dl_phdr_info {
	     Elf_Addr	     dlpi_addr;
	     const char      *dlpi_name;
	     const Elf_Phdr  *dlpi_phdr;
	     Elf_Half	     dlpi_phnum;
	     unsigned long long int dlpi_adds;
	     unsigned long long int dlpi_subs;
	     size_t	     dlpi_tls_modid;
	     void	     *dlpi_tls_data;
     };

     The members of struct dl_phdr_info have the following meaning:

     dlpi_addr	     The base address at which the object is mapped into the ad-
		     dress space of the calling process.

     dlpi_name	     The pathname of the ELF object.

     dlpi_phdr	     A pointer to the object's program headers.

     dlpi_phnum      The number of program headers in the object.

     dlpi_adds	     The  counter  of  the object loads performed by the dynamic
		     linker.

     dlpi_subs	     The counter of the object unloads performed by the  dynamic
		     linker.

     dlpi_tls_modid  The TLS index of the object.

     dlpi_tls_data   A	pointer to the calling thread' TLS data segment for this
		     module, if it was allocated, NULL otherwise.

     Future versions of FreeBSD might add more members to  this  structure.   To
     make  it  possible  for programs to check whether any new members have been
     added, the size of the  structure	is  passed  as	an  second  argument  to
     callback.

     The  third  argument  to  callback  is the data value passed to the call to
     dl_iterate_phdr(), allowing the callback to have a context.

RETURN VALUES
     The dl_iterate_phdr() returns the value returned by the last callback  call
     executed.

SEE ALSO
     ld(1), ld-elf.so.1(1), dlopen(3), elf(5)

HISTORY
     The dl_iterate_phdr function first appeared in FreeBSD 7.0.

FreeBSD ports 15.quarterly	  April 5, 2021 	      DL_ITERATE_PHDR(3)

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