Warning message

[simuumar]

When I compile the program I have the follwing message

In function 'int main()'

ignoring #pragma omp for

The code is following

#ifdef _OPENMP
#include <omp.h>
#endif
int main()
{
# pragma omp for
{
for (int i=0; i<=10 i++)
{}
}
return o;
can somebody help me.

}

[JosAH]

And what is "#pragma omp for" supposed to mean? Unknown pragmas are
supposed to be ignored by the compiler.

kind regards,

Jos

ps. I removed your email address for your own privacy.

[simuumar]

How I can execute the omp parallel directive
can you please mentioned what is the mistake.

[JosAH]

How I can execute the omp parallel directive
can you please mentioned what is the mistake.

I'm sure your manual describes all the nitty-gritty details about its own compiler's
pragma directives.

kind regards,

Jos

[Banfa]

simuumar, are you aware that #pragma is a directive to a specific compiler on a specific platform. The standard says little about them except that, as Jos says, unknown pragmas should be ignored by any compiler.

Part from that there is most no relationship between pragmas on 1 platform and another. Anything we could have to say about the pragmas we know would be completely irrelevant to your unknown platform.

To know how the pragam you have used or the pragma you want to use works you will need to read the documentation for your compiler/platform.

[simuumar]

Can u please send me any complete example.
please.so that i can understand.

[Banfa]

Here is an example

#pragma once

For the Microsoft Compiler (Visual C++/Visual Studio) when used in a header (.h) file it ensures that the file is only included into the code once in a way that is marginally more efficient than using #ifndef inclusion protection and speeds up complication marginally.

Some other compilers may support that pragma but there is no guarantee.

[simuumar]

Here is an example

#pragma once

For the Microsoft Compiler (Visual C++/Visual Studio) when used in a header (.h) file it ensures that the file is only included into the code once in a way that is marginally more efficient than using #ifndef inclusion protection and speeds up complication marginally.

Some other compilers may support that pragma but there is no guarantee.

# ifdef _OPENMP
# include < omp.h >
# endif
int main()
{
int i,id ;
#pragma once
{
for (i = 0; i<4; ++i )
{
int id = omp_get_thread_ num ();

return 0;

}
}
}


I am compiling the above code but its not working.Please help.
or correct the above please

[JosAH]

Banfa gave you an example for a compiler bound pragma; not something to be
copied/pasted (to the wrong location) and to be compiled without any understanding.

kind regards,

Jos

[simuumar]

Banfa gave you an example for a compiler bound pragma; not something to be
copied/pasted (to the wrong location) and to be compiled without any understanding.

kind regards,

Jos

Can I have some program using pragma

[JosAH]

Can I have some program using pragma

No; start reading your compiler manual.

Jos

ps. and don't repeat your same question over and over again. We have given
you the answers you need.

[simuumar]

No; start reading your compiler manual.

Jos

ps. and don't repeat your same question over and over again. We have given
you the answers you need.

so can u provide me some understanding. Atleast i can run the progrma please.Then I will understand automatically.

[JosAH]

so can u provide me some understanding. Atleast i can run the progrma please.Then I will understand automatically.

Banfa already gave you a perfect example: '#pragma once'; it belongs in a .h file
and not in a .c or .cpp file as was clearly explained. For other pragmas read your
fine compiler manual; I'm sure you'll find some. All pragmas are tied to a compiler,
i.e. they don't make sense for another compiler and are ignored, possibly after
issueing a warning message.

kind regards,

Jos

[donbock]

What compiler (version/vendor) are you using. Pragmas are compiler-specific. The examples you've been given are only valid for the compilers used by the respondents. It is truly impossible for anybody here to guess which pragmas are supported by your compiler. If you tell us your compiler vendor then there is a chance we can help you -- but there are no guarantees: you might be using a compiler unfamiliar to us.

By the way, are you using the same compiler that was used to originally write the code? If not, then you're porting the code to a new build environment. With careful discipline, C code can be written so that it ports uneventfully to another environment. On the other hand, C code can be written in ways that are a nightmare to port. Pragmas are one of the most nonportable parts of the language. If your code contains pragmas then I wonder if it contains other dependencies on nonportable features.

[RedSon]

so can u provide me some understanding. Atleast i can run the progrma please.Then I will understand automatically.

No one can provide you with some understanding, it is your responsibility to take what we have told you and learn from it. You will not understand automatically if someone wrote a program for you that has some pragma statements in it because you clearly don't have the slightest clue what pragma means.

Here is some information on the Microsoft compiler's pragma directives (http://msdn.microsoft.com/en-us/libr...05(VS.71).aspx) you can use it to get an idea of what they are but if you are not using Microsoft's compiler these directives will be useless for you.