dlsym(3) Library Functions Manual dlsym(3) dlsym, dlvsym - (libdl -ldl) #include void *dlsym(void *restrict handle, const char *restrict symbol); #define _GNU_SOURCE #include void *dlvsym(void *restrict handle, const char *restrict symbol, const char *restrict version); dlsym() "" dlopen(3) . dlopen(3) dlsym() NULL. ( dlsym() .) ( ) NULL . NULL dlsym() . NULL dlerror(3) dlsym() dlerror(3) NULL. handle: RTLD_DEFAULT . RTLD_GLOBAL. RTLD_NEXT . ( LD_PRELOAD ld.so(8)) "" ( "" ). _GNU_SOURCE RTLD_DEFAULT RTLD_NEXT . dlvsym() dlsym() . symbol. NULL dlerror(3). attributes(7). +------------+------------------------------------+--------------------+ || | | +------------+------------------------------------+--------------------+ |dlsym(), | | MT-Safe | |dlvsym() | | | +------------+------------------------------------+--------------------+ dlsym() POSIX.1-2008. dlvsym() GNU. dlsym() glibc 2.0. POSIX.1-2001. dlvsym() glibc 2.1. NULL. --defsym. NULL. GNU (IFUNC) NULL . dlsym() NULL . GNU : NULL dlsym() dlerror() . dlsym() dlopen SunOS. dlvsym(). dlopen(3). dl_iterate_phdr(3), dladdr(3), dlerror(3), dlinfo(3), dlopen(3), ld.so(8) 3 . . : . 6.18 8 2026 dlsym(3)