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libksquirrel/doc/html/ksquirrel-libs-olibs1.html

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<title>KSquirrel: development</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name='Author' content='Baryshev Dmitry/Krasu'>
<link rel="stylesheet" href="styles.css" type="text/css">
</head>
<body>
<ul>
<li>First, write regular C program (without main()):
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<pre>
const char* fmt_info()
{
return "It is really cool format!";
}
</pre>
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<li>Compile it
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<pre>
# gcc -O2 -fPIC -c module.c
# gcc -shared -o module.so module.o
</pre>
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<li>Let's write a simple test
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<pre>
#include &#60;unistd.h&#62;
#include &#60;string.h&#62;
#include &#60;errno.h&#62;
#include &#60;dlfcn.h&#62;
#define PATH_LENGTH 256
int main(int argc, char * argv[])
{
char path[PATH_LENGTH], *msg = NULL;
const char* (*fmt)();
void *module;
getcwd(path, PATH_LENGTH);
strcat(path, "/");
strcat(path, "module.so");
/* Load module */
module = dlopen(path, RTLD_NOW);
/* Error ! */
if(!module)
{
msg = dlerror();
if(msg != NULL)
{
dlclose(module);
exit(1);
}
}
/* Try to resolve function "fmt_info()" */
fmt = dlsym(module, "fmt_info");
msg = dlerror();
if(msg != NULL)
{
perror(msg);
dlclose(module);
exit(1);
}
/* call fmt_info() through a pointer*/
printf("%s\n", fmt());
/* close module */
if(dlclose(module))
{
perror("error");
exit(1);
}
return 0;
}
# gcc -o test main.c -ldl
# ./test
It is really cool format!
#
</pre>
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<li>That's all! :) Our test program has just loaded <u>module.so</u> and called <u>fmt_info()</u>, located in it. It is very simple, isn't ?
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