automatic reference to memset?

[Douglas Richardson]

To build a linux kernel module you must define a few things and include a
few header files.

The book "Linux Device Drivers" will show you how to write a simple module
quickly. You can view the book in PDF form at
http://www.xml.com/ldd/chapter/book/bookindexpdf.html.

Douglas Richardson.

-----Original Message-----
From: Shaya Potter [mailto:spotter@cs.columbia.edu]
Sent: Thursday, September 26, 2002 23:55
To: gcc-bugs@gcc.gnu.org
Subject: automatic reference to memset?


with the gcc included in debian ("2.95.4" a "debian prerelease") causes
gcc to cause a reference to memset to be automatically included.  Which
is very bad as this code is meant to be a snippet of code in a kernel
module, where obviously memset wont resolve.  I remove the devpts
decleration than there is no problem, so I'm guessing its related to the
fact that I declare it to be size 15 and I initilize it to a value. 
However, with red hat's gcc "2.96" and debian's gcc-3.2 (also called a
"debian prerelease") the code seems to compile normally.

this is driving me crazy, so if anyone can help I'd appreciate it

the sample code

extern int original_open(char *, int, int);

int zap_hook_open(char *filename, int flags, int mode)
{
        unsigned int fd;
        char devpts[15] = "/dev/pts/";
        char pts[4];

        fd = original_open(filename, flags, mode);

        return fd;
}

the .s produced

        .file   "test.c"
        .version        "01.01"
gcc2_compiled.:
.section        .rodata
.LC0:
        .string "/dev/pts/"
.globl memset
.text
        .align 4
.globl zap_hook_open
        .type    zap_hook_open,@function
zap_hook_open:
        pushl %ebp
        movl %esp,%ebp
        subl $40,%esp
        movl $.LC0,%eax
        movl (%eax),%edx
        movl %edx,-20(%ebp)
        movl 4(%eax),%edx
        movl %edx,-16(%ebp)
        movzwl 8(%eax),%eax
        movw %ax,-12(%ebp)
        leal -10(%ebp),%eax
        addl $-4,%esp
        pushl $5
        pushl $0
        pushl %eax
        call memset
        addl $16,%esp
        addl $-4,%esp
        movl 16(%ebp),%eax
        pushl %eax
        movl 12(%ebp),%eax
        pushl %eax
        movl 8(%ebp),%eax
        pushl %eax
        call original_open
        addl $16,%esp
        movl %eax,-4(%ebp)
        movl -4(%ebp),%edx
        movl %edx,%eax
        jmp .L2
        .p2align 4,,7
.L2:
        leave
        ret
.Lfe1:
        .size    zap_hook_open,.Lfe1-zap_hook_open
        .ident  "GCC: (GNU) 2.95.4 20011002 (Debian prerelease)"