With GCC 14.2, trying to include /usr/include/php/main/php.h fails

[jpbion]

Description

The following code, called 'j.c':

---

#include <stdio.h>
#include <php/main/php.h>

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

fprintf(stdout, "Hi!\n");
exit(0);
}

---

Compiled with PHP 8.3.10 and GCC 14.2.0, using the following command:

cc -o j -I /usr/include/php/Zend -I /usr/include/php -I /usr/include/php/main -I /usr/include/php/TSRM j.c

---

Resulted in this output:

In file included from /usr/include/php/Zend/zend.h:418,
from /usr/include/php/main/php.h:31,
from j.c:2:
/usr/include/php/Zend/zend_operators.h: In function 'zend_memrchr':
/usr/include/php/Zend/zend_operators.h:208:29: error: implicit declaration of function 'memrchr'; did you mean 'memchr'? [-Wimplicit-function-declaration]
208 | return (const void*)memrchr(s, c, n);
| ^~~~~~~
| memchr

---

Thoughts: The definitions in zend_operators.h worked with previous versions of gcc, but aren't happy with GCC 14.2, particularly with the reference to 'memrchr' which is not given an explicit declaration.

Now, my code may look quite random and arbitrary. But - it isn't. This code shows what happens when a C programmer happens to want to include "php.h" as a header file in their code - nothing more or less. I discovered this when attempting to have graphviz 12.0.0 build, and generate a PHP extension. Its check to see if php.h exists is pretty standard, and while this wasn't a problem pre-GCC 14.2, it is now.

I fear I won't be the only one running into this.

PHP Version

PHP 8.3.10

Operating System

Linux kernel 6.10.3 (LFS build)

[iluuu1994]

Your configuration seems to be inconsistent with your host system.

php-src/Zend/zend_operators.h

Lines 206 to 209 in 1d56340

	#if defined(HAVE_MEMRCHR) && !defined(i386)
	/* On x86 memrchr() doesn't use SSE/AVX, so inlined version is faster */
	return (const void*)memrchr(s, c, n);
	#else

HAVE_MEMRCHR seems to be defined, but the function doesn't actually exist. Can you please check where this definition is coming from? You may need to run the ./configure command, but I don't know the details about your build process, and I'm also no extension/sapi expert.

[jpbion]

I was able to recreate the problem without the reference to php.h... it appears that this is a problem in how "string.h" from glibc 2.40 exports an "extern" for memrchr... it does it correctly for memchr, but not memrchr. Now I'll have to dig into that, but this is a problem with my system's glibc I have to dig into (ugh...). But it's not a PHP issue, so this can be closed.

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

extern void *memrchr (void *__s, int __c, size_t __n);

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

char *x;
char *xptr;

x = malloc(100 * sizeof(char));
bzero(x, 100);
x[20] = 'c';
xptr = (char *) memrchr(x, (int) 'c', 100);
fprintf(stdout, "Hi xptr-x = %d!\n", (int) ((int) xptr - (int) x));
exit(0);
}

gcc -o j2 j2.c

If you don't have the extern definition of memrchr given above, it will fail at compilation with the new stricter requirements of GCC 14.

[iluuu1994]

Thank you for getting back to us! If there's anything else we can do, let me know.