Section: Linux Programmer's Manual (2)
uselib - load shared library
int uselib(const char *library);
No declaration of this system call is provided in glibc headers; see NOTES.
The system call
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
On success, zero is returned.
On error, -1 is returned, and
is set appropriately.
In addition to all of the error codes returned by
the following may also be returned:
The library specified by
does not have read or execute permission, or the caller does not have
search permission for one of the directories in the path prefix.
The system-wide limit on the total number of open files has been reached.
The file specified by
is not an executable of a known type;
for example, it does not have the correct magic numbers.
is Linux-specific, and should not be used in programs
intended to be portable.
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
In ancient libc versions,
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
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
This page is part of release 5.04 of the Linux
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