473,238 Members | 1,590 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,238 software developers and data experts.

simple command line parser

Well since getopt() doesn't seem to be compatible with Windows, and
the free implementation of it for Windows that I found still had some
annoying restrictions, I thought I'd whip up a simple parser myself.
Just wanted to see if anyone could provide me with some constructive
criticism :) any feedback would be greatly appreciated
-----------------------------------------------------------------------------

#include "stdio.h"
#include "string.h"
#include "stdlib.h"

#define MAX_OPTION_ARGS 10

enum optionName {
Start,
Stop,
Remove,
Install,
Debug,
Num_Opts
};

typedef struct optionStruct {
char *name;
int expNumVal;
char *val[MAX_OPTION_ARGS];
int valid;
} optStruct;

optStruct optData[Num_Opts] = {
{ "-start", 1 },
{ "-stop", 2 },
{ "-remove", 2 },
{ "-install", 1 },
{ "-debug", 3 }
};

int usage(void)
{
printf("Usage is as follows...");
return 0;
}

int StartService(char * service_name)
{
return 0;
}

int main (int argc, char * argv[])
{
int a, b, c;
const char *optstring;
const struct option *longopts;
int *longindex;

for (a = 1; a < argc; a++)
{
for (b = 0; b < Num_Opts; b++)
{
if (strcmp(argv[a], optData[b].name) == 0)
{
if (a + optData[b].expNumVal< argc)
{
for (c = 0; c < optData[b].expNumVal; c++)
{
optData[b].val[c] = argv[a + c + 1];
}
optData[b].valid = 1;
a += optData[b].expNumVal;
}
else
{
fprintf(stderr, "ERROR: insufficient number of arguments for
option %s\n", optData[b].name);
usage();
return 1;
}

break;
}
}

if (b == Num_Opts)
fprintf(stderr, "Warning: unknown option %s (ignored)\n", argv[a]);
}
/*
Sample usage...

if (optData[Start].valid == 1)
{
StartService(optData[Start].val[0]);

}
*/
return 0;
}
Nov 13 '05 #1
4 11414
ru******@hotmail.com (Greg B) wrote in
<f5**************************@posting.google.com >:
Well since getopt() doesn't seem to be compatible with Windows, and
the free implementation of it for Windows that I found still had some
annoying restrictions, I thought I'd whip up a simple parser myself.
Just wanted to see if anyone could provide me with some constructive
criticism :) any feedback would be greatly appreciated
-----------------------------------------------------------------------------

#include "stdio.h"
#include "string.h"
#include "stdlib.h"

#define MAX_OPTION_ARGS 10

enum optionName {
Start,
Stop,
Remove,
Install,
Debug,
Num_Opts
};

typedef struct optionStruct {
char *name;
int expNumVal;
char *val[MAX_OPTION_ARGS];
That's what I'd call an annoying restriction. :)
Why not char *val and dynamic memory allocation?
int valid;
} optStruct;

optStruct optData[Num_Opts] = {
{ "-start", 1 },
{ "-stop", 2 },
{ "-remove", 2 },
{ "-install", 1 },
{ "-debug", 3 }
}; Nice, you include the dash with every option name. :)

int usage(void)
{
printf("Usage is as follows...");
return 0;
}

int StartService(char * service_name)
{
return 0;
}
Please, don't use TABs for formatting code you post in usenet -
this wastes space and garbles the lines.
<code gently reformatted>int main (int argc, char * argv[])
{
int a, b, c;
const char *optstring;
const struct option *longopts;
int *longindex;

for (a = 1; a < argc; a++)
{
for (b = 0; b < Num_Opts; b++)
{
if (strcmp(argv[a], optData[b].name) == 0)
{
if (a + optData[b].expNumVal< argc)
{
for (c = 0; c < optData[b].expNumVal; c++)
{
optData[b].val[c] = argv[a + c + 1];
}
optData[b].valid = 1;
a += optData[b].expNumVal;
}
else
{
fprintf(stderr, "ERROR: insufficient number of arguments "
"for option %s\n", optData[b].name);
usage();
return 1;
}
break; This break has absolutely no chance of beeing executed!
}
}
if (b == Num_Opts)
fprintf(stderr, "Warning: unknown option %s (ignored)\n", argv[a]);
}
/*
Sample usage...

if (optData[Start].valid == 1)
{
StartService(optData[Start].val[0]);
}
*/
return 0;
}

Sorry, if my critique is somewhat destructive, but this is one of
the most complex option parsers I've been looking at. Anyway, if it
meets your needs, use it, but it might be a good idea to capsule it
in a separate module in order to keep your main function tidy and
clean. And you should consider not to make excessive use of global
variables, as this may lead to unwanted interferences eventually.

Btw: did you compile it? This is what I got when I did:

gcc.exe "D:\Temp\ngetopt.c" -o "D:\Temp\ngetopt.exe" -W -Wall
-Wunreachable-code -ansi -O3 -g3 -I"C:\Programme\DevCpp5b8\include"
-L"C:\Programme\DevCpp5b8\lib"

ngetopt.c:25: warning: missing initializer
ngetopt.c:25: warning: (near initialization for `optData[0].val')
ngetopt.c:26: warning: missing initializer
ngetopt.c:26: warning: (near initialization for `optData[1].val')
ngetopt.c:27: warning: missing initializer
ngetopt.c:27: warning: (near initialization for `optData[2].val')
ngetopt.c:28: warning: missing initializer
ngetopt.c:28: warning: (near initialization for `optData[3].val')
ngetopt.c:29: warning: missing initializer
ngetopt.c:29: warning: (near initialization for `optData[4].val')
ngetopt.c:46: warning: unused variable `optstring'
ngetopt.c:47: warning: unused variable `longopts'
ngetopt.c:48: warning: unused variable `longindex'
ngetopt.c:72: warning: will never be executed
ngetopt.c:38: warning: unused parameter `service_name'

If one takes warnings as errors (at least, I do), this is a /bit/
more than I'd expect from 86 lines of my code (though there are
no severe warnings, and you can get rid of them very easily).

I hope my reply wasn't to harsh... :)

Regards,
Irrwahn

--
When things look dark,
hold your head high so it can rain up your nose.
Nov 13 '05 #2
Irrwahn Grausewitz wrote:

ru******@hotmail.com (Greg B) wrote:
for (b = 0; b < Num_Opts; b++)
{
if (strcmp(argv[a], optData[b].name) == 0)
{
if (a + optData[b].expNumVal< argc)
{
for (c = 0; c < optData[b].expNumVal; c++)
{
optData[b].val[c] = argv[a + c + 1];
}
optData[b].valid = 1;
a += optData[b].expNumVal;
}
else
{
fprintf(stderr, "ERROR: insufficient number of arguments "
"for option %s\n", optData[b].name);
usage();
return 1;
}
break;

This break has absolutely no chance of beeing executed!


Why not?

--
Er*********@sun.com
Nov 13 '05 #3
Eric Sosman <Er*********@sun.com> wrote in <3F***************@sun.com>:
Irrwahn Grausewitz wrote:
ru******@hotmail.com (Greg B) wrote:
> break;

This break has absolutely no chance of beeing executed!


Why not?


Urgh, sorry, my fault. I'll go looking for my glasses... :)

--
Air is water with holes in it.
Nov 13 '05 #4
Greg B <ru******@hotmail.com> wrote:
Well since getopt() doesn't seem to be compatible with Windows, and
the free implementation of it for Windows that I found still had some
annoying restrictions, I thought I'd whip up a simple parser myself.
Just wanted to see if anyone could provide me with some constructive
criticism :) any feedback would be greatly appreciated
----------------------------------------------------------------------------- #include "stdio.h"
#include "string.h"
#include "stdlib.h"
Why are these in double-quotes? It would be more reasonable to
expect the compiler to look for these headers in their proper
locations to start with, not in the current directory.
#define MAX_OPTION_ARGS 10 enum optionName {
Start,
Stop,
Remove,
Install,
Debug,
Num_Opts
};
This has nothing to do with the rest of your code.
typedef struct optionStruct {
char *name;
int expNumVal;
char *val[MAX_OPTION_ARGS];
int valid;
} optStruct;
If you are going to be spelling out 'Struct' anyway, then why not
just lose the typedef? You will be saving yourself a shift-key hit.
If you insist on using the typedef, you do not need the structure
identifier, since you are not using it.
optStruct optData[Num_Opts] = {
{ "-start", 1 },
{ "-stop", 2 },
{ "-remove", 2 },
{ "-install", 1 },
{ "-debug", 3 }
};
Why not make the option prefix configurable via a define or somesuch?
Additionally, you should be initializing 'valid'.
int usage(void)
{
printf("Usage is as follows...");
return 0;
}
This is not terribly useful.
int StartService(char * service_name)
{
return 0;
}
Neither is this.

Here is your reindented code. Still unfitting line length for Usenet,
I'm afraid.
int
main (int argc, char *argv[])
{
int a, b, c;
const char *optstring;
You don't use this.
const struct option *longopts;
What is 'struct option'? You haven't defined it.
int *longindex;
You don't use this.
for (a = 1; a < argc; a++)
{
for (b = 0; b < Num_Opts; b++)
{
if (strcmp (argv[a], optData[b].name) == 0)
{
if (a + optData[b].expNumVal < argc)
{
This is where it gets really silly. You take the index of the
argv element you are parsing and add an offset to produce the
index of an expected supplementary value?
for (c = 0; c < optData[b].expNumVal; c++)
{
optData[b].val[c] = argv[a + c + 1];
}
optData[b].valid = 1;
a += optData[b].expNumVal;


Hmmm...

< snip the rest >

This is the most complicated and constrained way of getting
command-line arguments that I have ever seen.

You need to rethink your design by properly defining the problem
domain.

- What kind of options are you going to be parsing?

- Will there be only boolean options or will you have to handle
various supplementary types such as strings, integers, floats
and so on?

- What will happen if an option has incorrect syntax or a
a mandatory option is missing?

- Do you want to copy and paste code for each new program you
write or do you want to make a universally usable library
function, which will be configurable by the user?

To get you started, here is what I think your options structure
should look like.

enum opt_t { BOOL, INT, STR /*, etc */ }

struct option
{
char *opt; /* option name */
opt_t type; /* option type */
char mandatory; /* is option mandatory ? */
char *usage; /* usage for this specific option */
void *value; /* parsed value or null */
}

....only the last element is an output of the parser.

In your client code, you will populate an array of 'struct
option' and pass it to your parser along with argc and argv.

At any time if the parser fails, it will print out a program
usage based on the 'usage' fields in the array.

You should also leave it up the client code to define the prefix

Hope this helps.

Alex
Nov 13 '05 #5

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

4
by: Leif K-Brooks | last post by:
I'm writing a site with mod_python which will have, among other things, forums. I want to allow users to use some HTML (<em>, <strong>, <p>, etc.) on the forums, but I don't want to allow bad...
4
by: Boogie El Aceitoso | last post by:
Hi, I need a command line parser that understands filename swith spaces. Since I'm absolutelly sure I'm not the first developer to need a command line parser, I was wondering is there's a...
1
by: Larry | last post by:
I am a C++/Java programmer trying to get going with some simpe xml transformations at work here. I bought the O'Reilly book Learning xlst for kicks. Someone at work sent me this xml shown below,...
17
by: News | last post by:
Hi everyone, My goal is to pull command switches/options from a file and then assign the values to select variables which would eventually be included in a class object. The data file looks...
8
by: Andrew Robert | last post by:
Hi Everyone. I tried the following to get input into optionparser from either a file or command line. The code below detects the passed file argument and prints the file contents but the...
6
by: 31337one | last post by:
Hello all, I was wondering if there is a C/C++ command line parser that works for linux AND windows. . Anyways, the ideal parser im looking for should be able to support multiple arguments...
16
by: John Salerno | last post by:
Here's my new project: I want to write a little script that I can type at the terminal like this: $ scriptname package1 where scriptname is my module name and any subsequent arguments are the...
0
by: vincent90152900 | last post by:
I'm trying to get PowerShell script to run a program. Here is the command line I need to run: "\"C:\\Program Files\\PDF2allTest\\pdf2all\" -c pdf2jpg -s \"c:\\test\\test\\01.pdf\" -or 600" I...
4
by: cjt22 | last post by:
Hi there. I just wondered whether anyone could recommend the correct way I should be passing command line parameters into my program. I am currently using the following code: def main(argv =...
0
by: jianzs | last post by:
Introduction Cloud-native applications are conventionally identified as those designed and nurtured on cloud infrastructure. Such applications, rooted in cloud technologies, skillfully benefit from...
0
by: abbasky | last post by:
### Vandf component communication method one: data sharing ​ Vandf components can achieve data exchange through data sharing, state sharing, events, and other methods. Vandf's data exchange method...
2
isladogs
by: isladogs | last post by:
The next Access Europe meeting will be on Wednesday 7 Feb 2024 starting at 18:00 UK time (6PM UTC) and finishing at about 19:30 (7.30PM). In this month's session, the creator of the excellent VBE...
0
by: fareedcanada | last post by:
Hello I am trying to split number on their count. suppose i have 121314151617 (12cnt) then number should be split like 12,13,14,15,16,17 and if 11314151617 (11cnt) then should be split like...
0
by: stefan129 | last post by:
Hey forum members, I'm exploring options for SSL certificates for multiple domains. Has anyone had experience with multi-domain SSL certificates? Any recommendations on reliable providers or specific...
1
by: davi5007 | last post by:
Hi, Basically, I am trying to automate a field named TraceabilityNo into a web page from an access form. I've got the serial held in the variable strSearchString. How can I get this into the...
0
by: DolphinDB | last post by:
Tired of spending countless mintues downsampling your data? Look no further! In this article, you’ll learn how to efficiently downsample 6.48 billion high-frequency records to 61 million...
0
by: Aftab Ahmad | last post by:
So, I have written a code for a cmd called "Send WhatsApp Message" to open and send WhatsApp messaage. The code is given below. Dim IE As Object Set IE =...
0
isladogs
by: isladogs | last post by:
The next Access Europe meeting will be on Wednesday 6 Mar 2024 starting at 18:00 UK time (6PM UTC) and finishing at about 19:15 (7.15PM). In this month's session, we are pleased to welcome back...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.