From 507fafb0ade28b483f2e5d2b94bcf8a303303fb9 Mon Sep 17 00:00:00 2001
From: "rick.chan" <chenyang@autoai.com>
Date: Tue, 13 Apr 2021 09:43:53 +0800
Subject: [PATCH] =?UTF-8?q?=E5=A2=9E=E5=8A=A0=E7=AC=94=E8=AE=B0.?=
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Signed-off-by: rick.chan <chenyang@autoai.com>
---
 .../Applications/Objdump/Objdump_基本使用.md  |  6 +++
 .../Applications/Readelf/Readelf_基本使用.md  |  6 +++
 .../Standard/GCC/GCC_库导出符号控制.md        | 39 +++++++++++++++++++
 3 files changed, 51 insertions(+)
 create mode 100644 Software/Applications/Objdump/Objdump_基本使用.md
 create mode 100644 Software/Applications/Readelf/Readelf_基本使用.md
 create mode 100644 Software/Development/Standard/GCC/GCC_库导出符号控制.md

diff --git a/Software/Applications/Objdump/Objdump_基本使用.md b/Software/Applications/Objdump/Objdump_基本使用.md
new file mode 100644
index 0000000..909cc4e
--- /dev/null
+++ b/Software/Applications/Objdump/Objdump_基本使用.md
@@ -0,0 +1,6 @@
+# Objdump 基本使用
+
+```bash
+# 查看共享库符号表
+objdump -tT <shared library>
+```
diff --git a/Software/Applications/Readelf/Readelf_基本使用.md b/Software/Applications/Readelf/Readelf_基本使用.md
new file mode 100644
index 0000000..9935d48
--- /dev/null
+++ b/Software/Applications/Readelf/Readelf_基本使用.md
@@ -0,0 +1,6 @@
+# Readelf 基本使用
+
+```bash
+# 查看共享库符号表
+readelf -s <shared library>
+```
diff --git a/Software/Development/Standard/GCC/GCC_库导出符号控制.md b/Software/Development/Standard/GCC/GCC_库导出符号控制.md
new file mode 100644
index 0000000..560d2f8
--- /dev/null
+++ b/Software/Development/Standard/GCC/GCC_库导出符号控制.md
@@ -0,0 +1,39 @@
+# GCC 库导出符号控制
+
+GCC 编译库的时候默认导出所有符号。可通过指定以下参数选择默认的导出方案：
+
+```bash
+-fvisibility=default|internal|hidden|protected
+```
+
+如果设置成了 hidden，那么，可在函数前增加
+
+```cpp
+__attribute__ ((visibility("default")))
+```
+
+属性使其外部可见，或指定其属性。如：
+
+```cpp
+/**
+ * @file    example.c
+ */
+void func0(void)
+{
+    ...
+}
+
+__attribute__ ((visibility("default")))
+void func1(void)
+{
+    ...
+}
+```
+
+然后：
+
+```bash
+gcc -shared -o libexample.so -fvisibility=hidden example.c
+```
+
+则 void func1(void) 将被导出，而 void func0(void) 会被隐藏。