bionic (2) uselib.2.gz

NAME

       uselib - load shared library

SYNOPSIS

       #include <unistd.h>

       int uselib(const char *library);

       Note: No declaration of this system call is provided in glibc headers; see NOTES.

DESCRIPTION

       The  system call uselib() serves to load a shared library to be used by the calling process.  It is given
       a pathname.  The address where to load is found  in  the  library  itself.   The  library  can  have  any
       recognized binary format.

RETURN VALUE

       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

ERRORS

       In  addition  to  all  of  the  error  codes  returned  by open(2) and mmap(2), the following may also be
       returned:

       EACCES The library specified by library does not have read or execute permission, or the caller does  not
              have   search   permission   for   one   of  the  directories  in  the  path  prefix.   (See  also
              path_resolution(7).)

       ENFILE The system-wide limit on the total number of open files has been reached.

       ENOEXEC
              The file specified by library is not an executable of a known type; for example, it does not  have
              the correct magic numbers.

CONFORMING TO

       uselib() is Linux-specific, and should not be used in programs intended to be portable.

NOTES

       This  obsolete  system call is not supported by glibc.  No declaration is provided in glibc headers, but,
       through a quirk of history, glibc  versions  before  2.23  did  export  an  ABI  for  this  system  call.
       Therefore,  in  order  to employ this system call, it was sufficient to manually declare the interface in
       your code; alternatively, you could invoke the system call using syscall(2).

       In ancient libc versions, uselib() was used to load the shared libraries with names found in an array  of
       names in the binary.

       Since  libc  4.3.2, startup code tries to prefix these names with "/usr/lib", "/lib" and "" before giving
       up.  In libc 4.3.4 and later these names are looked for in the directories found in LD_LIBRARY_PATH,  and
       if not found there, prefixes "/usr/lib", "/lib" and "/" are tried.

       From  libc  4.4.4  on  only the library "/lib/ld.so" is loaded, so that this dynamic library can load the
       remaining libraries needed (again using this call).  This is also the state of affairs in libc5.

       glibc2 does not use this call.

       Since Linux 3.15, this system call is available only when the kernel is configured with the CONFIG_USELIB
       option.

SEE ALSO

       ar(1), gcc(1), ld(1), ldd(1), mmap(2), open(2), dlopen(3), capabilities(7), ld.so(8)

COLOPHON

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       https://www.kernel.org/doc/man-pages/.