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uselib() - Unix, Linux System Call


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NAME

uselib - load shared library

SYNOPSIS

#include <unistd.h> 

int uselib(const char *library);

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:

TagDescription
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(2).)
ENFILE The system limit on the total number of open files has been reached.
ENOEXEC
  The file specified by library is not an executable of known type, e.g., 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

uselib() was used by early libc startup code 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.

SEE ALSO



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