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Command: rtld_set_var | Section: 3 | Source: FreeBSD | File: rtld_set_var.3.gz
RTLD_GET_VAR(3) FreeBSD Library Functions Manual RTLD_GET_VAR(3)
NAME
rtld_get_var, rtld_set_var - query or change run-time linker parameters
after image activation
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/errno.h>
#include <link.h>
const char *
rtld_get_var(const char *name);
int
rtld_set_var(const char *name, const char *value);
DESCRIPTION
The dynamic linker rtld(1) can be configured by setting some environment
variables for the process, before image activation. Sometimes it is
desirable to query the current effective settings or change them
afterward.
Since the process environment variables are maintained by higher-level
libraries, the run-time linker cannot access them after the image
activation. The described functions make it possible to operate on rtld
settings.
The rtld_get_var() function returns the current value of the named
parameter.
The rtld_set_var() functions changes the value of the parameter to the
new value value, if possible. The name argument to both functions is the
name of the parameter, which is same as the corresponding environment
variable (see rtld(1)) but without the LD_ (or LD_32_ or any other ABI-
specific) prefix.
RETURN VALUES
The rtld_get_var() returns the current value of the named parameter, or
NULL if the name is invalid.
The rtld_set_var() returns 0 on success, or an integer indicating the
error condition which prevented the operation.
ERRORS
Possible errors returned from rtld_set_var():
[EPERM] The requested change cannot be made at runtime, either
because the runtime linker can only take this
parameter at initialization time, or because the
current process is executing with elevated privileges.
[ENOENT] The supplied parameter name is unknown.
SEE ALSO
rtld(1)
HISTORY
The rtld_get_var function first appeared in FreeBSD 14.3.
FreeBSD 14.1-RELEASE-p8 October 31, 2024 FreeBSD 14.1-RELEASE-p8