USELIB
Section: Linux Programmer's Manual (2)
Updated: 2017-09-15
Index
Return to Main Contents
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
This page is part of release 4.13 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/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-
|
|
- Running on 
-
:
: 