rt-thread-official/components/libc/posix/libdl/dlsym.c

45 lines
1.3 KiB
C

/*
* Copyright (c) 2006-2024 RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2010-11-17 yi.qiu first version
*/
#include <rtthread.h>
#include <rtm.h>
#include "dlmodule.h"
/**
* @brief look up the address of a symbol in a dynamically loaded shared library.
*
* @param handle the handle returned by dlopen() when the library was previously loaded.
* @param symbol A string containing the name of the symbol to locate.
* @return void* On success, it returns a pointer to the symbol. Otherwise, it returns RT_NULL.
*
* @note This function is an API of POSIX standard, which is commonly used in conjunction with dlopen() to retrieve function pointers from shared libraries.
* the input symbol name, which can be the name of a function or variable, is compared with each symbol
* in the module symbol table. if the same symbol is found, return its address.
*/
void* dlsym(void *handle, const char* symbol)
{
int i;
struct rt_dlmodule *module;
RT_ASSERT(handle != RT_NULL);
module = (struct rt_dlmodule *)handle;
for(i=0; i<module->nsym; i++)
{
if (rt_strcmp(module->symtab[i].name, symbol) == 0)
return (void*)module->symtab[i].addr;
}
return RT_NULL;
}
RTM_EXPORT(dlsym)