* Making gcc read from the standard input
@ 2007-01-11 6:31 Tathagato Rai Dastidar
2007-01-11 9:12 ` Paolo Bonzini
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Tathagato Rai Dastidar @ 2007-01-11 6:31 UTC (permalink / raw)
To: gcc-help, gcc
Hello,
Is there a way I can make GCC read a C or C++ code from the standard input
instead of from a file?
In my application software, I am generating some C code on the fly, writing it
to a file, then using GCC to compile it. Instead of that, I want to invoke GCC
through a pipe, and write the C code directly into GCC, instead of writing it
into a file and then calling GCC.
Is this possible?
Regards,
Tathagato Rai Dastidar
Prinicipal Software Engineer,
National Semiconductor Corp.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Making gcc read from the standard input
2007-01-11 6:31 Making gcc read from the standard input Tathagato Rai Dastidar
@ 2007-01-11 9:12 ` Paolo Bonzini
2007-01-11 13:56 ` John Love-Jensen
2007-01-11 17:06 ` Mike Stump
2 siblings, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2007-01-11 9:12 UTC (permalink / raw)
To: Tathagato Rai Dastidar, gcc-help, GCC Development
Tathagato Rai Dastidar wrote:
> Hello,
>
> Is there a way I can make GCC read a C or C++ code from the standard
> input instead of from a file?
>
> In my application software, I am generating some C code on the fly,
> writing it to a file, then using GCC to compile it. Instead of that, I
> want to invoke GCC through a pipe, and write the C code directly into
> GCC, instead of writing it into a file and then calling GCC.
>
> Is this possible?
This is a question only for gcc-help. Cross-posting gcc and gcc-help is
almost always wrong. :-) But yes, it is possible by adding "-x c" to
the command line, so that the gcc driver knows which front-end to
invoke. In the case of "-E", in fact, GCC implicitly considers the
language to be C (and invokes the C front-end) because the preprocessor
is the same for all input languages; but for real compilation, you need
to specify the language manually.
HTH,
Paolo
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Making gcc read from the standard input
2007-01-11 6:31 Making gcc read from the standard input Tathagato Rai Dastidar
2007-01-11 9:12 ` Paolo Bonzini
@ 2007-01-11 13:56 ` John Love-Jensen
2007-01-11 17:06 ` Mike Stump
2 siblings, 0 replies; 4+ messages in thread
From: John Love-Jensen @ 2007-01-11 13:56 UTC (permalink / raw)
To: Tathagato Rai Dastidar, MSX to GCC
Hi Tathagato,
[Removed gcc@gcc.gnu.org reply-to]
> Is there a way I can make GCC read a C or C++ code from the standard input
> instead of from a file?
Yes, definitely. :-)
I do this (an Eljay original!), for example, to use GCC's preprocessor to
grep for Carbon API information:
carbon ()
{
echo '#include <Carbon/Carbon.h>' \
| g++ -H -x c++ -c -o /dev/null - 2>&1 \
| sed -e 's/^[. ]*//' \
| sort -u \
| tr '\n' '\0' \
| xargs -0 grep "$@"
}
Notice the g++ line? I'm using the -x c++ to specify "interpret as C++",
and the - all by itself means "source comes from stdin".
I'm sending output to /dev/null, since I really just want the -H information
for this little quick-and-dirty Carbon grep'per.
HTH,
--Eljay
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Making gcc read from the standard input
2007-01-11 6:31 Making gcc read from the standard input Tathagato Rai Dastidar
2007-01-11 9:12 ` Paolo Bonzini
2007-01-11 13:56 ` John Love-Jensen
@ 2007-01-11 17:06 ` Mike Stump
2 siblings, 0 replies; 4+ messages in thread
From: Mike Stump @ 2007-01-11 17:06 UTC (permalink / raw)
To: Tathagato Rai Dastidar; +Cc: gcc-help
On Jan 10, 2007, at 10:29 PM, Tathagato Rai Dastidar wrote:
> Is there a way I can make GCC read a C or C++ code from the
> standard input instead of from a file?
$ echo 'int i;' | gcc -S -xc - -o -
.comm _i,16
.subsections_via_symbols
Also, some systems have things like /dev/fd0 and /dev/stdin. They
are files that can be read, even if gcc didn't support the "-" filename.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2007-01-11 6:31 Making gcc read from the standard input Tathagato Rai Dastidar
2007-01-11 9:12 ` Paolo Bonzini
2007-01-11 13:56 ` John Love-Jensen
2007-01-11 17:06 ` Mike Stump
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