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"#" directive affects compilation ?
- From: "Michael Gong" <mwgong at cs dot utoronto dot ca>
- To: <gcc-help at gcc dot gnu dot org>
- Date: Tue, 9 Jan 2007 10:24:46 -0500
- Subject: "#" directive affects compilation ?
Hi, all,
It might be a basic question. I always think that the "#" directive in
the preprocessed file won't affect compilation, but following example
shows that I am wrong. Can anyone give a quick explanation ?
/* t1.c */
# 1 "foo.c"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "foo.c"
# 1 "/usr/include/stdlib.h" 1 3
# 25 "/usr/include/stdlib.h" 3
# 1 "/usr/include/features.h" 1 3
# 295 "/usr/include/features.h" 3
# 1 "/usr/include/sys/cdefs.h" 1 3
# 296 "/usr/include/features.h" 2 3
# 318 "/usr/include/features.h" 3
# 1 "/usr/include/gnu/stubs.h" 1 3
# 319 "/usr/include/features.h" 2 3
# 26 "/usr/include/stdlib.h" 2 3
# 1 "/usr/lib/gcc-lib/i386-redhat-linux/3.2.3/include/stddef.h" 1 3
# 213 "/usr/lib/gcc-lib/i386-redhat-linux/3.2.3/include/stddef.h" 3
typedef unsigned int size_t;
extern void *malloc (size_t __size) __attribute__ ((__malloc__));
char * malloc();
/* end of t1.c */
"t1.c" is compiled successfully to generate a ".o" file.
But if I remove all the "#" directives, following error message will be
shown:
t1.c:22: conflicting types for `malloc'
t1.c:21: previous declaration of `malloc'
Therefore, it shows that "#" directives does affect compilation. Is that
correct ?
Regards,
Mike