USELIB(2)                 (2020-12-21)                  USELIB(2)

     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 pre-
               fix.  (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 pro-
          grams 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

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     USELIB(2)                 (2020-12-21)                  USELIB(2)

          interface in your code; alternatively, you could invoke the
          system call using syscall(2).

          In ancient libc versions (before glibc 2.0), uselib() was
          used to load the shared libraries with names found in an
          array of names in the binary.

          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
          This page is part of release 5.10 of the Linux man-pages
          project.  A description of the project, information about
          reporting bugs, and the latest version of this page, can be
          found at https://www.kernel.org/doc/man-pages/.

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