using c with html interface

[Vivek]

Hi,
I got the method of invoking a c executable code from the html.I tested
the invocation by writing a simple C
program that accepts two integers from the html page, multiplies them
and returns the result to the html page.
I have coded a program that uses sockets to communicate with the other
computer.
The OS used is Red Hat linux. When i call the executable file of this
program, the socket() function returns with an error. i.e the socket()
function call returns a negative value hence is unable to create
a socket.

However, when i execute the program on the command line in linux, the
program executes as expected and communicates with the other machine.

Please let me know as to how I can invoke the socket program using the
html interface.

[Tom St Denis]

Vivek wrote:

Hi,
I got the method of invoking a c executable code from the html.I tested
the invocation by writing a simple C
program that accepts two integers from the html page, multiplies them
and returns the result to the html page.

You mean a CGI right? As far as I know Apache doesn't have SSI for C
programs.

I have coded a program that uses sockets to communicate with the other
computer.
The OS used is Red Hat linux. When i call the executable file of this
program, the socket() function returns with an error. i.e the socket()
function call returns a negative value hence is unable to create
a socket.

Off topic, but use perror() to give you a hint.

Tom

[Vivek]

Tom St Denis wrote:

You mean a CGI right? As far as I know Apache doesn't have SSI for C
programs.

Off topic, but use perror() to give you a hint.

Tom

I can't relate how SSI will affect the invocation of the C-executable
which uses sockets for inter-machine. SSI just provides a handler which
will process files before they are sent to the client.
The c program will handle the socket communication whereas the html
will just provide the UI.

However, I haven't understood what happens internally(i.e within the
browser) when the executable file is invoked from the html.

The way c program is written is by including the following in any c
code.,
#include<stdlib.h>
printf("%s%c%c\n","Content-type: text/html;charset=iso-8859-1",13,10);
//The type is text/html

data = getenv("QUERY_STRING"); //QUERY_STRING contains the parameters
passed from the
//web page(eg;-
"m=12&n=10")
any subsequent printf() statements will print in the html page.

In the html the call is done as usual,
<form method="GET" action="/cgi-bin/test.cgi" test.cgi is the
executable file got by compiling
test.c

My issue is, when i do the same stuff in a c program which has socket
programming, the html
page appears but the socket() function call fails and returns a
negative value.

[Ico]

Vivek <ia********@gmail.comwrote:

>
My issue is, when i do the same stuff in a c program which has socket
programming, the html page appears but the socket() function call
fails and returns a negative value.

Like the previous poster said, use perror() or look at the value of the
errno variable to see while the socket() call failed.

--
:wq
^X^Cy^K^X^C^C^C^C

[mbstevens]

Vivek wrote:

Hi,
I got the method of invoking a c executable code from the html.I tested
the invocation by writing a simple C
program that accepts two integers from the html page, multiplies them
and returns the result to the html page.
I have coded a program that uses sockets to communicate with the other
computer.

Unless you're doing something like writing a
server, you should be communicating with a
running server through the CGI interface.

The OS used is Red Hat linux.

Then you probably already have the Apache
server on your machine, ready to fire up
after a bit of configuration. If not, you
install disk will have it.

[Keith Thompson]

"Vivek" <ia********@gmail.comwrites:

I got the method of invoking a c executable code from the html.I tested
the invocation by writing a simple C
program that accepts two integers from the html page, multiplies them
and returns the result to the html page.
I have coded a program that uses sockets to communicate with the other
computer.
The OS used is Red Hat linux.

This is off-topic. Standard C doesn't have any support for html or
sockets. Try a Linux-specific group, or comp.unix.programmer.

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Brian C]

Vivek wrote:

Hi,
I got the method of invoking a c executable code from the html.I tested
the invocation by writing a simple C
program that accepts two integers from the html page, multiplies them
and returns the result to the html page.
I have coded a program that uses sockets to communicate with the other
computer.
The OS used is Red Hat linux. When i call the executable file of this
program, the socket() function returns with an error. i.e the socket()
function call returns a negative value hence is unable to create
a socket.

However, when i execute the program on the command line in linux, the
program executes as expected and communicates with the other machine.

Please let me know as to how I can invoke the socket program using the
html interface.

This is off-topic (try comp.unix.programmer), but ... why are you trying
to establish a connection via a socket() with the client? Any output you
want should just be output to stdout, you don't need to establish a
socket connection to the peer.