Disable printf

[RedDevilDan]

I am working on a Memory Footprint Reduction project. I came across an
idea to disable all printf statements so that less memory is required.
In addition, when there is no single printf statement, the printf
library will not be linked, so it further reduces the executable size.
Is there an easy way to disable printf in a large project? In my
project, we have thousands of C & C++ files. They don't have a common
included common header. Otherwise, I can do a #define printf(x) in the
common header. I am using GNU GCC compiler and run the program in both
Linux and VxWorks platform.

Any of you have a suggestion on disabling all printf statements?

I also think about to add a common header file into the whole project.
However, I would need to put a #include "common.h" line into each c
file. It's gonna take a while to do that. Is there any way to insert
the line automatically into each c file?

[Richard Tobin]

In article <11************ **********@j44g 2000cwa.googleg roups.com>,
RedDevilDan <kl******@yahoo .comwrote:

>I am working on a Memory Footprint Reduction project. I came across an
idea to disable all printf statements so that less memory is required.

If you can add a header to each file, and you are using GCC, you can
put this in it (inside an ifdef that checks for GCC):

extern int printf(const char *format, ...) __attribute__ ((deprecated));

which will result in the message

warning: 'printf' is deprecated

when you compile a file that calls printf.

-- Richard
--
"Considerat ion shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

[Ben Bacarisse]

jaysome <ja*****@spamco p.netwrites:

On 30 Nov 2006 17:58:34 -0800, "RedDevilDa n" <kl******@yahoo .com>
wrote:

>>I am working on a Memory Footprint Reduction project.

<snip>

>>They don't have a common
included common header. Otherwise, I can do a #define printf(x) in the
common header. I am using GNU GCC compiler and run the program in both
Linux and VxWorks platform.

<snip>

The Microsoft Visual C++ compiler provides the /FI compiler option

<snip>

I don't know if gcc has a similar option.

Now OT, but yes, it has -include <fileand the even more useful
-imacros <fileoption.

--
Ben.

[Ben Pfaff]

jaysome <ja*****@spamco p.netwrites:

If the OP had something like the Microsoft VC++ /FI option, as
described else-thread, he would have intuitively modified a Makefile
file or project file and added a header file and have been done with
it. That's adept, adroit, agile, astute, and, ultimately, awesome.

....and can be rather a surprise when something goes wrong,
because there's nothing in the source code indicating that the
header file gets included.
--
"...deficie nt support can be a virtue.
It keeps the amateurs off."
--Bjarne Stroustrup

[Fred Kleinschmidt]

"RedDevilDa n" <kl******@yahoo .comwrote in message
news:11******** **************@ j44g2000cwa.goo glegroups.com.. .

>I am working on a Memory Footprint Reduction project. I came across an
idea to disable all printf statements so that less memory is required.
In addition, when there is no single printf statement, the printf
library will not be linked, so it further reduces the executable size.
Is there an easy way to disable printf in a large project? In my
project, we have thousands of C & C++ files. They don't have a common
included common header. Otherwise, I can do a #define printf(x) in the
common header. I am using GNU GCC compiler and run the program in both
Linux and VxWorks platform.

Any of you have a suggestion on disabling all printf statements?

I also think about to add a common header file into the whole project.
However, I would need to put a #include "common.h" line into each c
file. It's gonna take a while to do that. Is there any way to insert
the line automatically into each c file?

Using a macro to disable printf will not work in the general case.
Suppose you had this:
#define printf(x)
or even using the variadic C99
#define printf(x,...)

But printf is a function that returns an int. Think what will happens if the
code contains:
if ( printf(....) != n ) {...}

One way around this is to add your own printf function that does nothing:

int printf( char *fmt, ... ) {}

--
Fred L. Kleinschmidt
Boeing Associate Technical Fellow
Technical Architect, Software Reuse Project

[Richard Heathfield]

Fred Kleinschmidt said:

>
"RedDevilDa n" <kl******@yahoo .comwrote in message

<snip>

>>
Any of you have a suggestion on disabling all printf statements?

<snip>

>
One way around this is to add your own printf function that does nothing:

int printf( char *fmt, ... ) {}

4.1.2 of C89 says: "All external identifiers declared in any of the headers
are reserved, whether or not the associated header is included."

7.1.3 of C99 says: "- Each identifier with file scope listed in any of the
following subclauses (including the future library directions) is reserved
for use as a macro name and as an identifier with file scope in the same
name space if any of its associated headers is included."

So - if you have a C99 compiler, that's fine **provided** that you don't
need anything else from <stdio.h>! But if you don't have a C99 compiler, it
ain't at all fine.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.

[d3x0xr]

#define printf( f,...) (1)

// or zero, printf can be used in an expression and needs to be an
expression result.
// that's it.

// provided you have a c99 compiler. GCC, OpenWatcom,...

RedDevilDan:

I am working on a Memory Footprint Reduction project. I came across

an

idea to disable all printf statements so that less memory is

required.

In addition, when there is no single printf statement, the printf
library will not be linked, so it further reduces the executable

size.

Is there an easy way to disable printf in a large project? In my
project, we have thousands of C & C++ files. They don't have a

common

included common header. Otherwise, I can do a #define printf(x) in

the

common header. I am using GNU GCC compiler and run the program in

both

Linux and VxWorks platform.

Any of you have a suggestion on disabling all printf statements?

I also think about to add a common header file into the whole

project.

However, I would need to put a #include "common.h" line into each c
file. It's gonna take a while to do that. Is there any way to

insert

the line automatically into each c file?

[Harald van Dijk]

Richard Heathfield wrote:

Fred Kleinschmidt said:

"RedDevilDa n" <kl******@yahoo .comwrote in message

<snip>

>
Any of you have a suggestion on disabling all printf statements?

<snip>

One way around this is to add your own printf function that does nothing:

int printf( char *fmt, ... ) {}

4.1.2 of C89 says: "All external identifiers declared in any of the headers
are reserved, whether or not the associated header is included."

7.1.3 of C99 says: "- Each identifier with file scope listed in any of the
following subclauses (including the future library directions) is reserved
for use as a macro name and as an identifier with file scope in the same
name space if any of its associated headers is included."

So - if you have a C99 compiler, that's fine **provided** that you don't
need anything else from <stdio.h>! But if you don't have a C99 compiler, it
ain't at all fine.

7.1.3 of C99 also says "All identi�ers with external linkage in any
of the following subclauses (including the future library directions)
are always reserved for use as identi�ers with external linkage."

It's not fine in C99, even if you don't use anything from <stdio.h>.

[Richard Heathfield]

Harald van Dijk said:

<snip>

>
7.1.3 of C99 also says "All identifiers with external linkage in any
of the following subclauses (including the future library directions)
are always reserved for use as identifiers with external linkage."

It's not fine in C99, even if you don't use anything from <stdio.h>.

Good spot. Even without that, it's impractical (because just about every
program needs *something* from stdio.h), but with it, it's a wipe-out.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.

[Ed Prochak]

Richard Heathfield wrote:

Harald van Dijk said:

<snip>

7.1.3 of C99 also says "All identifiers with external linkage in any
of the following subclauses (including the future library directions)
are always reserved for use as identifiers with external linkage."

It's not fine in C99, even if you don't use anything from <stdio.h>.

Good spot. Even without that, it's impractical (because just about every
program needs *something* from stdio.h), but with it, it's a wipe-out.

--
Richard Heathfield

I wonder why no one has suggested the real solution. Replace the
library.
But I guess that solution is really outside the realm of C.

Ed

[Arthur J. O'Dwyer]

On Fri, 30 Nov 2006, William Hughes wrote:

RedDevilDan wrote:

>Thanks for the reply at first.

I tried the gcc -D "printf(x)= " way. However, it complains about the
printf(x) at the stdio.h, "/usr/include/stdio.h:329:58: macro "printf"
passed 2 arguments, but takes just 1"
I guess the gcc doesn't know how to handle the std c lib if you
redefine printf

Probably no. More likely the problem is that printf is a variadic
function (takes a varying number of arguments) so you need to
replace it a variadic macro.

Probably, the problem is that that line in stdio.h is

extern int printf(const char *fmt, ...);

which --- even with a variadic macro --- will become something like

extern int ((void)0);

which is just plain wrong. The most correct answers, already provided
by other posters, are "don't do that", "get a new library (without
printf)", and "get a new compiler (which can optimize out dead code)".

-Arthur,
intentionally conflating the concepts of "compiler" and "linker"