How can I write commands to the vxworks shell with a c program

Question

If I wanted to run a shell command in linux with a c program, I would use

system("ls");

Is there a way I can accomplish this in Wind River vxworks?

I found the below example but I'm wondering do I need to include vxworks header files for this to work? I assume I do, but how do I figure out which one?

Example:

//  This function runs a shell command and captures the output to the
//  specified file
//

extern int consoleFd;
typedef unsigned int             (*UINTFUNCPTR) ();

extern "C" int shellToFile(char * shellCmd, char * outputFile)
{
int rtn;
int STDFd;
int outFileFd;

   outFileFd = creat( outputFile, O_RDWR);

   printf("creat returned %x as a file desc\n",outFileFd);

   if (outFileFd != -1)  
   {  
    STDFd=ioGlobalStdGet(STD_OUT);  
      ioGlobalStdSet(STD_OUT,outFileFd);  
      rtn=execute(shellCmd);  
   if (rtn !=0)  
    printf("execute returned %d \n",outFileFd);  
      ioGlobalStdSet(STD_OUT,STDFd);  

   }  
   close(outFileFd);  
   return (rtn);  
}  

Answer 1

I think that the ExecCmd function is what you are looking for.

http://www.dholloway.com/vxworks/6.5/man/cat2/ExecCmd.shtml

Answer 2

If this is a target/kernel shell (i.e. running on the target itself), then remember that all the shell commands are simply translated to function calls.

Thus "ls" really is a call to ls(), which I believe is declared in dirLib.h

Answer 3

As ever, read the documentation. ioLib.h is required for most of the functions used in that example, and stdio.h of course for printf().

As to the general question of whether you need to include any particular headers for any code to compile, you do need to declare all symbols used, and generally that means including appropriate headers. The compiler will soon tell you about any undefined symbols, either by warning or error (in C89/90 undefined functions are not an error, just a bad idea).

Answer 4

I found the code segment below worked for me. For some reason changing the globalStdOut didn't work. Also the execute function did not work for me. But my setting the specific task out to my file, I was able to obtain the data I needed.

/* This function directs the output from the devs command into a new file*/

int devsToFile(const char * outputFile)
{
int stdTaskFd;
int outputFileFd;

outputFileFd = creat( outputFile, O_RDWR);

if (outputFileFd != ERROR)
    {

    stdTaskFd = ioTaskStdGet(0,1);
    ioTaskStdSet(0,1,outputFileFd);
    devs();
    ioTaskStdSet(0,1,stdTaskFd);
    close(outputFileFd);
    return (OK);
    }
else
    return (ERROR);

}