[PATCH] alloca.3: correct information on getting non-inlined version with gcc+glibc

[PATCH] alloca.3: correct information on getting non-inlined version with gcc+glibc

[Adrian Bunk]

- remove the incorrect information that -fno-builtin would help
- add -std=c11 to the list of strict options
- emphasize more that both the gcc option and not including
  alloca.h are needed
- add the #ifdef from the glibc alloca.h to make the situation clearer

Signed-off-by: Adrian Bunk <bunk-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 man3/alloca.3 |   16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/man3/alloca.3 b/man3/alloca.3
index 73b88f5..0d593ed 100644
--- a/man3/alloca.3
+++ b/man3/alloca.3
@@ -40,7 +40,7 @@
 .\"     Various rewrites and additions (notes on longjmp() and SIGSEGV).
 .\"     Weaken warning against use of alloca() (as per Debian bug 461100).
 .\"
-.TH ALLOCA 3 2008-01-24 "GNU" "Linux Programmer's Manual"
+.TH ALLOCA 3 2013-05-12 "GNU" "Linux Programmer's Manual"
 .SH NAME
 alloca \- allocate memory that is automatically freed
 .SH SYNOPSIS
@@ -110,20 +110,22 @@ This is not done when either the
 .IR "\-std=c89" ,
 .IR "\-std=c99" ,
 or the
-.IR "\-fno\-builtin"
+.IR "\-std=c11"
 option is given
-(and the header
+.BR and
+the header
 .I <alloca.h>
-is not included).
-But beware!
-By default the glibc version of
+is not included.
+Otherwise (without an \-ansi or \-std=c* option) the glibc version of
 .I <stdlib.h>
 includes
 .I <alloca.h>
-and that contains the line:
+and that contains the lines:
 .nf
 
+    #ifdef  __GNUC__
     #define alloca(size)   __builtin_alloca (size)
+    #endif
 
 .fi
 with messy consequences if one has a private version of this function.
-- 
1.7.10.4

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Re: [PATCH] alloca.3: correct information on getting non-inlined version with gcc+glibc

[Michael Kerrisk]

On 05/12/13 13:26, Adrian Bunk wrote:
> - remove the incorrect information that -fno-builtin would help
> - add -std=c11 to the list of strict options
> - emphasize more that both the gcc option and not including
>   alloca.h are needed
> - add the #ifdef from the glibc alloca.h to make the situation clearer
> 
> Signed-off-by: Adrian Bunk <bunk-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

Thanks, Adrian. Applied.

Cheers,

Michael


> ---
>  man3/alloca.3 |   16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/man3/alloca.3 b/man3/alloca.3
> index 73b88f5..0d593ed 100644
> --- a/man3/alloca.3
> +++ b/man3/alloca.3
> @@ -40,7 +40,7 @@
>  .\"     Various rewrites and additions (notes on longjmp() and SIGSEGV).
>  .\"     Weaken warning against use of alloca() (as per Debian bug 461100).
>  .\"
> -.TH ALLOCA 3 2008-01-24 "GNU" "Linux Programmer's Manual"
> +.TH ALLOCA 3 2013-05-12 "GNU" "Linux Programmer's Manual"
>  .SH NAME
>  alloca \- allocate memory that is automatically freed
>  .SH SYNOPSIS
> @@ -110,20 +110,22 @@ This is not done when either the
>  .IR "\-std=c89" ,
>  .IR "\-std=c99" ,
>  or the
> -.IR "\-fno\-builtin"
> +.IR "\-std=c11"
>  option is given
> -(and the header
> +.BR and
> +the header
>  .I <alloca.h>
> -is not included).
> -But beware!
> -By default the glibc version of
> +is not included.
> +Otherwise (without an \-ansi or \-std=c* option) the glibc version of
>  .I <stdlib.h>
>  includes
>  .I <alloca.h>
> -and that contains the line:
> +and that contains the lines:
>  .nf
>  
> +    #ifdef  __GNUC__
>      #define alloca(size)   __builtin_alloca (size)
> +    #endif
>  
>  .fi
>  with messy consequences if one has a private version of this function.
> 

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