如何编译动态库？

Question

我已经在网上搜索了几天，但似乎找不到关于如何执行此操作的明确说明。

SQLite没有正弦，余弦等数学函数。我找到了一个扩展SQLite并添加这些函数的库，但我不知道如何编译该库。

http://lhealy.livejournal.com/6306.html

我已经尝试了几乎所有内容（解决方案除外）。 我下载了SQLite源，配置并使用了make，然后尝试在扩展的源目录中使用以下命令来构建动态库。

gcc -fPIC func_ext.c -shared -o libsqlitefunctions.so -Isqlite3 -Isqlite3 / src

我在此目录中包含sqlite3源，因此-I标志应指向正确的目录。 这是我得到的错误。

func_ext.c:91: error: static declaration of ‘acosh’ follows non-static declaration
func_ext.c:99: error: static declaration of ‘asinh’ follows non-static declaration
func_ext.c:107: error: static declaration of ‘atanh’ follows non-static declaration
func_ext.c:403: error: conflicting types for ‘isblank’
/usr/include/ctype.h:242: error: previous definition of ‘isblank’ was here
func_ext.c: In function ‘properFunc’:
func_ext.c:422: warning: pointer targets in passing argument 1 of ‘sqlite3StrDup’ differ in signedness
func_ext.c:422: warning: pointer targets in assignment differ in signedness
func_ext.c: In function ‘padlFunc’:
func_ext.c:463: warning: pointer targets in assignment differ in signedness
func_ext.c: In function ‘padrFunc’:
func_ext.c:509: warning: pointer targets in assignment differ in signedness
func_ext.c: In function ‘padcFunc’:
func_ext.c:556: warning: pointer targets in assignment differ in signedness
func_ext.c: In function ‘strfilterFunc’:
func_ext.c:607: warning: pointer targets in assignment differ in signedness
func_ext.c:608: warning: pointer targets in assignment differ in signedness
func_ext.c:616: warning: pointer targets in passing argument 1 of ‘sqlite3ReadUtf8’ differ in signedness
func_ext.c:618: warning: pointer targets in passing argument 1 of ‘sqlite3ReadUtf8’ differ in signedness
func_ext.c: In function ‘_substr’:
func_ext.c:654: warning: pointer targets in passing argument 1 of ‘sqlite3ReadUtf8’ differ in signedness
func_ext.c:659: warning: pointer targets in passing argument 1 of ‘sqlite3ReadUtf8’ differ in signedness
func_ext.c:664: warning: pointer targets in passing argument 1 of ‘sqlite3ReadUtf8’ differ in signedness
func_ext.c:665: warning: pointer targets in passing argument 1 of ‘sqlite3ReadUtf8’ differ in signedness
func_ext.c: In function ‘charindexFunc’:
func_ext.c:716: warning: pointer targets in passing argument 1 of ‘_substr’ differ in signedness
func_ext.c:716: warning: pointer targets in passing argument 2 of ‘_substr’ differ in signedness
func_ext.c: In function ‘rightFunc’:
func_ext.c:775: warning: pointer targets in assignment differ in signedness
func_ext.c:779: warning: pointer targets in passing argument 1 of ‘sqlite3ReadUtf8’ differ in signedness
func_ext.c: In function ‘ltrimFunc’:
func_ext.c:833: warning: pointer targets in assignment differ in signedness
func_ext.c: In function ‘rtrimFunc’:
func_ext.c:851: warning: pointer targets in assignment differ in signedness
func_ext.c: In function ‘trimFunc’:
func_ext.c:872: warning: pointer targets in assignment differ in signedness
func_ext.c: In function ‘replaceFunc’:
func_ext.c:914: warning: pointer targets in assignment differ in signedness
func_ext.c:915: warning: pointer targets in assignment differ in signedness
func_ext.c:916: warning: pointer targets in assignment differ in signedness
func_ext.c: In function ‘reverseFunc’:
func_ext.c:975: warning: pointer targets in assignment differ in signedness
func_ext.c:982: warning: pointer targets in passing argument 1 of ‘sqlite3ReadUtf8’ differ in signedness
func_ext.c: In function ‘differenceFunc’:
func_ext.c:1336: warning: pointer targets in passing argument 1 of ‘sqlite3ReadUtf8’ differ in signedness
func_ext.c:1336: warning: pointer targets in passing argument 1 of ‘sqlite3ReadUtf8’ differ in signedness

谢谢！ 桑德罗

Answer 1

考虑使用g ++代替gcc，后者会在编译c ++时自动设置正确的设置。 例如，使用以下代码：

int f(int x)
{

}

int f(int x, int y)
{

}

int main(int argc, char* argv[])
{

}

...给出错误：

test.c:7: error: conflicting types for ‘f’
test.c:2: error: previous definition of ‘f’ was here

与g ++一样，这很好。 可能是代码确实在试图成为c，并且正在定义重载，这将是非法的，并且是一个更大的问题，但是我首先要试一下。

Answer 2

这些是编译器错误，而不是链接器错误。
您需要考虑使程序进行编译（以常规方式），然后才能考虑将其构建为共享库。