How to connect external C/C++ libraries in Zend PHP extension

Question

I am trying to make a .so PHP extension written in C using Zend framework. With stand-alone extension everything is OK. But if I try to use some other dynamic-linking library in my extension, I get the following error:

PHP Warning:  dl(): Unable to load dynamic library '/usr/lib/php5/20121212/test.so' - /usr/lib/php5/20121212/test.so: undefined symbol: _Z5hellov in /var/www/test.php on line 2
PHP Fatal error:  Call to undefined function my_function() in /var/www/test.php on line 3

I have compiled libhello.so and copied to the same directory /usr/lib/php5/20121212/ How can I use it from test.so module?

Here is the source code:

test.c:

#include "php.h"
#include "hello.h"

ZEND_FUNCTION( my_function );
ZEND_FUNCTION(Hello);

zend_function_entry firstmod_functions[] =
{
ZEND_FE(my_function, NULL)
    ZEND_FE(Hello, NULL)
    {NULL, NULL, NULL}
};

zend_module_entry firstmod_module_entry =
{
    STANDARD_MODULE_HEADER,
    "First Module",
    firstmod_functions,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NO_VERSION_YET,
STANDARD_MODULE_PROPERTIES
};

ZEND_GET_MODULE(firstmod)

ZEND_FUNCTION( my_function )
{
    char *str; int str_len;
    long l;
    if(ZEND_NUM_ARGS() != 2) WRONG_PARAM_COUNT; 

    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sl", 
        &str, &str_len, &l) == FAILURE) {
        return;
    }

    zend_printf("%s  \r\n", str);
    zend_printf("%ld \r\n", l);

    RETURN_LONG(1);

}

ZEND_FUNCTION (Hello) {
    hello();
}

hello.h:

#include <stdio.h>

void hello();

hello.c:

#include "hello.h"

void hello () {
printf("%s\n", "Hello, world!");
}

test.php:

<?php
dl("test.so");
my_function("123",12);
    Hello();
?>

hek2mgl · Accepted Answer · 2013-11-15 20:58:13Z

2

In order to make a function visible to the php userland you need to use the macro PHP_FUNCTION():

hello.h:

PHP_FUNCTION(hello_world);

test.c:

ZEND_BEGIN_ARG_INFO_EX(arginfo_hello_world, 0, 0, 2)
    ZEND_ARG_INFO(0, arg1_name)
    ZEND_ARG_INFO(0, arg2_name)
ZEND_END_ARG_INFO()


...


const zend_function_entry pcap_functions[] = { 
    ...
    PHP_FE(my_function, arginfo_hello_world)
    ...
};


...
PHP_FUNCTION( my_function )
{
    char *str; int str_len;
    long l;
    if(ZEND_NUM_ARGS() != 2) WRONG_PARAM_COUNT; 

    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sl", 
        &str, &str_len, &l) == FAILURE) {
        return;
    }

    zend_printf("%s  \r\n", str);
    zend_printf("%ld \r\n", l);

    RETURN_LONG(1);

}

...

edited Nov 15, 2013 at 20:58

answered Nov 15, 2013 at 20:53

hek2mgl

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