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DL_ITERATE_PHDR(3)    DragonFly Library Functions Manual    DL_ITERATE_PHDR(3)

NAME
     dl_iterate_phdr -- iterate over program headers

LIBRARY
     This function is not in a library.  It is included in every dynamically
     linked program automatically.

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 shared objects loaded
     into a process's address space, calling callback for each shared object,
     passing it information about the object's program headers and the data
     argument.  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 shared object is mapped into
                   the address space of the calling process.

     dlpi_name     The name of the shared object.

     dlpi_phdr     A pointer to the shared object's program headers.

     dlpi_phnum    The number of program headers in the shared object.

     dlpi_adds     The number of objects added into the main program.

     dlpi_subs     The number of objects removed from the main program.

     To make it possible for programs to check whether any new members have
     been added, the size of the structure is passed as an argument to
     callback.

RETURN VALUES
     The dl_iterate_phdr() function returns whatever value was returned by the
     last call to callback.

EXAMPLES
     The following program displays a list of pathnames of the shared objects
     it has loaded.  For each shared object, the program lists the virtual
     addresses at which the object's ELF segments are loaded.

     #include <link.h>
     #include <stdlib.h>
     #include <stdio.h>

     static int
     callback(struct dl_phdr_info *info, size_t size, void *data)
     {
         int j;
         printf("name=%s (%d segments)\n", info->dlpi_name,
             info->dlpi_phnum);
         for (j = 0; j < info->dlpi_phnum; j++)
              printf(" header %2d: address=%10p\n", j,
                  (void *) (info->dlpi_addr + info->dlpi_phdr[j].p_vaddr));
         return 0;
     }

     int
     main(int argc, char *argv[])
     {
         dl_iterate_phdr(callback, NULL);
         exit(EXIT_SUCCESS);
     }

SEE ALSO
     ld(1), ld-elf.so.2(1), dlfcn(3), elf(5)

HISTORY
     The dl_iterate_phdr function first appeared in DragonFly 2.9.

DragonFly 5.5                   April 28, 2011                   DragonFly 5.5