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Date: Mon, 23 Dec 2002 23:51:42 +0100
Message-ID: <3E00A20100008131@mail-8.tiscalinet.it>
From: fabrizio_ge-wolit AT tiscali DOT it
Subject: Strange behaviour of gcc
To: cygwin AT cygwin DOT com
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Can somebody explain why gcc (version 3.2 20020927) on Cygwin does this?
Type this simple C program

void func(void){
  struct {unsigned char data[3985];}var;
}

and compile with

gcc -c filename.c

Then type

nm filename.o

The output is

00000000 b .bss
00000000 d .data
00000000 t .text
         U __alloca
00000000 T _func

Why on earth is the symbol __alloca doing there?

Just change the program to

void func(void){
  struct {unsigned char data[3984];}var;
}

and compile it. This time, nm's output is

00000000 b .bss
00000000 d .data
00000000 t .text
00000000 T _func

as it should. Is there a reason why the symbol __alloca appears?

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