Programming

Hi

Im launching another applicaTION from my "C" program.
Is there any way to capture the application output only.

Example.

printf ("U have pressed 1\n");
system("ls -l");
printf (" U have launched a command\n");


Any way to capture only output from the system ("ls -l") command.
Other 2 printf statements should be print on the terminal.

You need to call popen(), not system. Check the man page for popen.

This link has a code example using an ls call with popen
popen

popen is only used to execute a shell command.
But how to capture through tee command which is built in C.
vmsplice or splice.

Thanks in advance

You can redirect the program's output to a file. This file will has the output you need. At last, you can remove this temporary file by calling the remove() command, ex: remove(file); where file is a char * containing the file's name.
For example:
system(ls -l > temp);
//code ... you can use temp t see the output ...
remove(temp);

But sometimes I need to load a shared object and call the function.
In that case the function will be opened and prints messages (log messages) on the terminal.

Loading shared library using dlopen(),locating the function in so using dlsym and executing the function.
Here is the problem.

int (*abc)(int , int)
handle=dlopen("shareobject.so", RTLD_NOW);
abc =dlsym(handle,"fw");

//Executing function "fw" like
(*abc)(x,y)


In this case I need to capture the output only from the last statement.

#include <stdio.h>

main()
{
int fd;
fpos_t pos;
printf("First Line\n");

fflush(stdout);
fgetpos(stdout, &pos);
fd = dup(fileno(stdout));
freopen("stdout.out", "w", stdout);

system("ls -l");

fflush(stdout);
dup2(fd, fileno(stdout));
close(fd);
clearerr(stdout);
fsetpos(stdout, &pos);

printf("Last line again to stdout\n");
}