Thread: Issue reading program arguments

  1. #1
    Registered User awsdert's Avatar
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    Issue reading program arguments

    Someone tell if this output makes sense to them in relation to the code below (start with bottom function - "ProcessArgv") it because it sure doesn't to me.

    Output:
    Code:
    make run ARGS="--detailed=2 --quiet-zlib -f ./pngsuite/s01n3p01.png"
    ...
    ./a.out --detailed=2 --quiet-zlib -f ./pngsuite/s01n3p01.png
    main.c:506: Analysing argument '--quiet-zlib'
    main.c:506: Analysing argument '-f'
    main.c:421: ArgHasIssue( '--quiet-zlib', '(null)' )
    main.c:506: Analysing argument './pngsuite/s01n3p01.png'
    main.c:421: ArgHasIssue( '--quiet-zlib', './pngsuite/s01n3p01.png' )
    view/png.c:330:  IDAT bytes =    31
    ...
    Code:
    #define OUTPUT_ERRORS 1
    #define OUTPUT_VERBOSE 2
    #define OUTPUT_DETAILED 4
    int shut_output = 0;
    ALLOC l_alloc = {0};
    char *image_file = "./openstreetmap.png";
    
    void SetVerbose( char const *path )
    {
    	if ( path )
    	{
    		if ( strcmp( path, "2" ) == 0 )
    		{
    			l_alloc.verbose = stderr;
    			return;
    		}
    
    		if ( strlen( path ) > 1 )
    		{
    			l_alloc.verbose = fopen( path, "w" );
    			shut_output |= OUTPUT_VERBOSE;
    			return;
    		}
    	}
    
    	l_alloc.verbose = stdout;
    }
    
    int ArgHasIssue( char *arg, char *val )
    {
    	ECHO
    	(
    		l_alloc.errors,
    		fprintf( l_alloc.errors, "ArgHasIssue( '%s', '%s' )\n", arg, val )
    	);
    
    	if ( !val )
    	{
    		val = strchr( arg, '=' );
    
    		if ( val )
    			++val;
    	}
    
    	if ( strstr( arg, "--quiet-zlib" ) == arg )
    	{
    		quiet_zlib = true;
    		return 0;
    	}
    
    	if ( strstr( arg, "--verbose" ) == arg )
    	{
    		SetVerbose( val );
    		l_alloc.errors = l_alloc.verbose;
    		return 0;
    	}
    
    	if ( strstr( arg, "--detailed" ) == arg )
    	{
    		if ( !l_alloc.verbose )
    		{
    			SetVerbose( val );
    			l_alloc.errors = l_alloc.verbose;
    		}
    
    		l_alloc.detailed = l_alloc.verbose;
    		return 0;
    	}
    
    	if ( arg[1] == 'f' )
    	{
    		if ( !val )
    		{
    			ECHO
    			(
    				l_alloc.errors,
    				fprintf( l_alloc.errors, "No path declared '%s'\n", val )
    			)
    			return EINVAL;
    		}
    
    		if ( access(val, 0) != 0 )
    		{
    			ECHO
    			(
    				l_alloc.errors,
    				fprintf( l_alloc.errors, "Couldn't find '%s'\n", val )
    			)
    			return EACCES;
    		}
    
    		image_file = val;
    		return 0;
    	}
    
    	return EINVAL;
    }
    
    int ArgHadIssue( int err, char *arg )
    {
    	FILE *errors = l_alloc.errors;
    	ECHO( errors, ECHO_ERR( errors, err ) );
    	ECHO( errors, fprintf( errors, "Invalid argument '%s'\n", arg ) );
    	fprintf( errors, "Usage: APP [--verbose,--detailed,-f PATH]\n" );
    	return EXIT_FAILURE;
    }
    
    int ProcessArgv( int argc, char **argv )
    {
    	int a;
    	char *prv = NULL;
    
    	ECHO( l_alloc.errors, fprintf( l_alloc.errors, "ProcessArgv( %c, %p )\n", argc, (void*)argv ) );
    
    	for ( a = 0; a < argc; ++a )
    	{
    		int err;
    		char *arg = argv[a];
    
    		ECHO( l_alloc.errors, fprintf( l_alloc.errors, "Analysing argument '%s'\n", arg ) );
    
    		if ( !arg )
    			continue;
    
    		if ( arg[0] == '-' )
    		{
    			if ( prv )
    			{
    				err = ArgHasIssue( prv, NULL );
    
    				if ( err )
    					return ArgHadIssue( err, arg );
    
    				continue;
    			}
    
    			if ( strchr( arg, '=' ) )
    			{
    				err = ArgHasIssue( arg, NULL );
    
    				if ( err )
    					return ArgHadIssue( err, arg );
    
    				continue;
    			}
    
    			prv = arg;
    			continue;
    		}
    
    		if ( !prv )
    		{
    			if ( a > 0 )
    				return ArgHadIssue( EINVAL, arg );
    			continue;
    		}
    
    		err = ArgHasIssue( prv, arg );
    
    		if ( err )
    			return ArgHadIssue( err, arg );
    
    		prv = NULL;
    	}
    
    	if ( prv )
    	{
    		int err = ArgHasIssue( prv, NULL );
    
    		if ( err )
    			return ArgHadIssue( err, prv );
    	}
    
    	return 0;
    }

  2. #2
    and the hat of int overfl Salem's Avatar
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    And your reason for not using getopt is?
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  3. #3
    Registered User awsdert's Avatar
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    Quote Originally Posted by Salem View Post
    And your reason for not using getopt is?
    Only seen that name once years ago, forgot all about it until now, the fact that I chose not to use it then indicates to me it couldn't satisfy a requirement of mine, I suspect it was a portability issue like not being part of the C standard, anyways it appears the prints were executing but due to a crash that happens later it somehow got ignored. Either way I've chosen a slightly simpler method of argument handling:

    Code:
    int ArgHasIssue( int a, int num, char *argv[] )
    {
    	char *arg = (a >= 0) ? argv[a] : NULL;
    	char *val = (arg && num) ? argv[a+num] : NULL;
    
    	ECHO
    	(
    		l_alloc.errors,
    		fprintf
    		(
    			l_alloc.errors,
    			"ArgHasIssue( %d, %d, %p ) arg = '%s', val = '%s'\n",
    			a,
    			num,
    			(void*)argv,
    			arg ? arg : argv[0],
    			val
    		)
    	);
    
    	if ( !arg )
    		return 0;
    
    	if ( !val )
    	{
    		val = strchr( arg, '=' );
    
    		if ( val )
    			++val;
    	}
    
    	if ( strstr( arg, "--q-zlib" ) )
    	{
    		quiet_zlib = true;
    		return 0;
    	}
    
    	if ( strstr( arg, "--verbose" ) )
    	{
    		SetVerbose( val );
    		l_alloc.errors = l_alloc.verbose;
    		return 0;
    	}
    
    	if ( strstr( arg, "--detailed" ) )
    	{
    		if ( !l_alloc.verbose )
    		{
    			SetVerbose( val );
    			l_alloc.errors = l_alloc.verbose;
    		}
    
    		l_alloc.detailed = l_alloc.verbose;
    		return 0;
    	}
    
    	if ( arg[1] == 'f' )
    	{
    		if ( !val )
    		{
    			ECHO
    			(
    				l_alloc.errors,
    				fprintf( l_alloc.errors, "No path declared '%s'\n", val )
    			)
    			return EINVAL;
    		}
    
    		if ( access(val, 0) != 0 )
    		{
    			ECHO
    			(
    				l_alloc.errors,
    				fprintf( l_alloc.errors, "Couldn't find '%s'\n", val )
    			)
    			return EACCES;
    		}
    
    		image_file = val;
    		return 0;
    	}
    
    	return EINVAL;
    }
    
    int ArgHadIssue( int err, int a, int num, char *argv[] )
    {
    	int stop = a + num;
    	FILE *errors = l_alloc.errors;
    	ECHO( errors, ECHO_ERR( errors, err ) );
    	ECHO( errors, fprintf( errors, "Invalid argument/s: " ) );
    
    	do fprintf( errors, " %s", argv[a++] ); while ( a < stop );
    
    	fprintf( errors, "\nUsage: APP [--verbose,--detailed,-f PATH]\n" );
    	return EXIT_FAILURE;
    }
    
    int ProcessArgv( int argc, char **argv )
    {
    	int a, i = -1, num = 0, err;
    
    	ECHO( l_alloc.errors, fprintf( l_alloc.errors, "ProcessArgv( %d, %p )\n", argc, (void*)argv ) );
    
    	for ( a = 0; a < argc; ++a )
    	{
    		char *arg = argv[a];
    
    		ECHO( l_alloc.errors, fprintf( l_alloc.errors, "Analysing argument '%s'\n", arg ) );
    
    		if ( !arg || arg[0] == '-' )
    		{
    			if ( num )
    			{
    				err = ArgHasIssue( i, num, argv );
    
    				if ( err )
    					return ArgHadIssue( err, i, num, argv );
    			}
    
    			i = a;
    			num = 0;
    
    			if ( arg && strchr( arg, '=' ) )
    			{
    				err = ArgHasIssue( i, num, argv );
    
    				if ( err )
    					return ArgHadIssue( err, i, num, argv );
    			}
    
    			continue;
    		}
    
    		++num;
    	}
    
    	if ( num )
    	{
    		err = ArgHasIssue( i, num, argv );
    
    		if ( err )
    			return ArgHadIssue( err, i, num, argv );
    	}
    
    	return 0;
    }
    Which is giving me this output at the moment:
    Code:
    make debug ARGS="--detailed=2 --q-zlib -f ./pngsuite/s01n3p01.png"
    ...
    ./d.out --detailed=2 --q-zlib -f ./pngsuite/s01n3p01.png
    main.c:517: ProcessArgv( 5, 0x7ffd6453da78 )
    main.c:523: Analysing argument './d.out'
    main.c:523: Analysing argument '--detailed=2'
    main.c:433: ArgHasIssue( -1, 1, 0x7ffd6453da78 ) arg = './d.out', val = '(null)'
    main.c:433: ArgHasIssue( 1, 0, 0x7ffd6453da78 ) arg = '--detailed=2', val = '(null)'
    main.c:523: Analysing argument '--q-zlib'
    main.c:523: Analysing argument '-f'
    main.c:523: Analysing argument './pngsuite/s01n3p01.png'
    main.c:433: ArgHasIssue( 3, 1, 0x7ffd6453da78 ) arg = '-f', val = './pngsuite/s01n3p01.png'
    Attempting to open ./openstreetmap.png
    view/png.c:330:  IDAT bytes =    31
    buff/zlib.c:814: ExpandZlibArchive( 0x7ffd6453b878 )
    last = 0, type = 00
    buff/zlib.c:467: leng = 60801, nlen = 449
    ...
    view/png.c:484: ScanLines( 0x7ffd6453b7e0 )
    d.out: malloc.c:2539: sysmalloc: Assertion `(old_top == initial_top (av) && old_size == 0) || ((unsigned long) (old_size) >= MINSIZE && prev_inuse (old_top) && ((unsigned long) old_end & (pagesize - 1)) == 0)' failed.
    make: *** [GNUmakefile:46: debug] Aborted (core dumped)
    Compilation failed.
    Trying to figure out why "--q-zlib" is being ignored at the moment

  4. #4
    Registered User awsdert's Avatar
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    Never mind, fixed it, now I just need to fix the source of the crash.

    Code:
    int ProcessArgv( int argc, char **argv )
    {
    	int a, i = -1, num = 0, err;
    
    	ECHO( l_alloc.errors, fprintf( l_alloc.errors, "ProcessArgv( %d, %p )\n", argc, (void*)argv ) );
    
    	for ( a = 0; a < argc; ++a )
    	{
    		char *arg = argv[a];
    
    		ECHO( l_alloc.errors, fprintf( l_alloc.errors, "Analysing argument '%s'\n", arg ) );
    
    		if ( !arg || arg[0] == '-' )
    		{
    			if ( num || i >= 0 )
    			{
    				err = ArgHasIssue( i, num, argv );
    
    				if ( err )
    					return ArgHadIssue( err, i, num, argv );
    			}
    
    			i = a;
    			num = 0;
    
    			continue;
    		}
    
    		++num;
    	}
    
    	if ( num || i >= 0 )
    	{
    		err = ArgHasIssue( i, num, argv );
    
    		if ( err )
    			return ArgHadIssue( err, i, num, argv );
    	}
    
    	return 0;
    }
    In case anyone wants to help me find the source of memory corruption that is causing the crash I'll be uploading my current code in a minute, I'll edit this post to contain the link after

    Edit: As promised, here's the link:

    Files * 148969b2657cb6a5650f6995ade9a0f133f18880 * Lee Shallis / glEngine * GitLab

  5. #5
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    What am I missing? 175 lines?

    Code:
    #include <stdio.h>
    #include <string.h>
    #include <stdlib.h>
    
    
    const char verbose_opt[] = "--verbose";
    const char detailed_opt[] = "--detailed";
    
    
    int main(int argc, char *argv[]) {
       int i = 1;
    
       // Default for verbose off and detailed is off
       int verbose = 0, detailed = 0;
       char *path = NULL;
    
       while(i != argc) {
         if(strncmp(argv[i], verbose_opt, strlen(verbose_opt))==0) {
             verbose = 1;
             if(argv[i][strlen(verbose_opt)] == '=')
               verbose = atoi(argv[i]+strlen(verbose_opt)+1);
             else if(argv[i][strlen(verbose_opt)] != '\0')
               break;
             i++;
         } else if(strncmp(argv[i], detailed_opt, strlen(detailed_opt))==0) {
             detailed = 1;
             if(argv[i][strlen(detailed_opt)] == '=')
               verbose = atoi(argv[i]+strlen(detailed_opt)+1);
             else if(argv[i][strlen(detailed_opt)] != '\0')
               break;
             i++;
         } else if(strcmp(argv[i],"-f")==0 && i != argc-1) {
             if(path)
                 break; // Specifed file name twice
             path = argv[i+1];
             i+=2;
         } else {
             break; // Option not expected
         }
       }
    
       // Check all options have been processed, and we have a path
       if(path == NULL || i != argc) {
         fprintf( stderr, "Usage: %s [--verbose,--detailed,-f PATH]\n", argv[0] );
         return 1;
       }
    
       printf("Verbose  %i\n",verbose);
       printf("Detailed %i\n",detailed);
       printf("Path     %s\n",path);
       return 0;
    }
    Last edited by hamster_nz; 08-12-2021 at 05:58 AM.

  6. #6
    Registered User awsdert's Avatar
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    Quote Originally Posted by hamster_nz View Post
    What am I missing? 175 lines?

    Code:
    #include <stdio.h>
    #include <string.h>
    #include <stdlib.h>
    
    
    const char verbose_opt[] = "--verbose";
    const char detailed_opt[] = "--detailed";
    
    
    int main(int argc, char *argv[]) {
       int i = 1;
    
       // Default for verbose off and detailed is off
       int verbose = 0, detailed = 0;
       char *path = NULL;
    
       while(i != argc) {
         if(strncmp(argv[i], verbose_opt, strlen(verbose_opt))==0) {
             verbose = 1;
             if(argv[i][strlen(verbose_opt)] == '=')
               verbose = atoi(argv[i]+strlen(verbose_opt)+1);
             else if(argv[i][strlen(verbose_opt)] != '\0')
               break;
             i++;
         } else if(strncmp(argv[i], detailed_opt, strlen(detailed_opt))==0) {
             detailed = 1;
             if(argv[i][strlen(detailed_opt)] == '=')
               verbose = atoi(argv[i]+strlen(detailed_opt)+1);
             else if(argv[i][strlen(detailed_opt)] != '\0')
               break;
             i++;
         } else if(strcmp(argv[i],"-f")==0 && i != argc-1) {
             if(path)
                 break; // Specifed file name twice
             path = argv[i+1];
             i+=2;
         } else {
             break; // Option not expected
         }
       }
    
       // Check all options have been processed, and we have a path
       if(path == NULL || i != argc) {
         fprintf( stderr, "Usage: %s [--verbose,--detailed,-f PATH]\n", argv[0] );
         return 1;
       }
    
       printf("Verbose  %i\n",verbose);
       printf("Detailed %i\n",detailed);
       printf("Path     %s\n",path);
       return 0;
    }
    Sure that probably works but I like my method more, it's easier to handle common errors and avoid copying memory unnecessarily. Plus it helps keep main() simpler, and with the amount of test code I currently have in main() for the glengine project I really do need a simpler main() function, I plan to move the code into another file later so that all argument handling has it's own dedicated file, eventually I want have main only handle the initialisation & cleanup of objects that are to be passed around, argument handling does not belong directly in main() for that kind of plan.

  7. #7
    Registered User rstanley's Avatar
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    awsdert:
    In reference to getopt() and getopt_long():

    Only seen that name once years ago, forgot all about it until now, the fact that I chose not to use it then indicates to me it couldn't satisfy a requirement of mine,
    What requirement?

    I suspect it was a portability issue like not being part of the C standard, anyways it appears the prints were executing but due to a crash that happens later it somehow got ignored.
    It may not be part of the C Standard, but is so common, that is not an issue. There are version for Windows as well.

    Either way I've chosen a slightly simpler method of argument handling
    I would NOT consider your code, "a slightly simpler method"! Try coding a version using getopt() or getopt_long().

  8. #8
    Registered User awsdert's Avatar
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    Quote Originally Posted by rstanley View Post
    awsdert:
    In reference to getopt() and getopt_long():

    What requirement?

    It may not be part of the C Standard, but is so common, that is not an issue. There are version for Windows as well.

    I would NOT consider your code, "a slightly simpler method"! Try coding a version using getopt() or getopt_long().
    You realise getopt() & getopt_long() probably also have similarly complex code right? Mine just happens to be in full view, whereas the other 2 you have to hunt it down on the net

  9. #9
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    Quote Originally Posted by awsdert View Post
    You realise getopt() & getopt_long() probably also have similarly complex code right? Mine just happens to be in full view, whereas the other 2 you have to hunt it down on the net
    They are also already written and work quite well.

    Something something about reinventing the wheel.

  10. #10
    Registered User rstanley's Avatar
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    Quote Originally Posted by awsdert View Post
    You realise getopt() & getopt_long() probably also have similarly complex code right? Mine just happens to be in full view, whereas the other 2 you have to hunt it down on the net
    So are printf(), scanf() and many other Standard Library functions that you would rather use than rewrite from scratch! Getopt() and getopt_long() are frameworks written, debugged, and proven, that you just use. I don't have to "Hunt down" the actual code, I just use it!

    I don't want to spend vast amounts of time hard coding Command Line Argument options, and other non-option arguments, or end up with 175 lines of complicated code. How much work will it take to Add/Change/Delete some of your options, plus track down intermittent bugs? Very little when using getopt() or getopt_long()!

    Why do you consistently fight the excellent advise you are given by more experienced programmers? Some of us have been there, doen that, made mistakes and learned from those mistakes. Why ask for advice when it will just be ignored when we offer it??? You wonder why readers don't respond to many of your postings!!!

    getopt() may not be part of the C Standard, but is, "POSIX.1-2001, POSIX.1-2008, and POSIX.2"

    Please review the code examples in the man page link above.

  11. #11
    Registered User awsdert's Avatar
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    Quote Originally Posted by rstanley View Post
    So are printf(), scanf() and many other Standard Library functions that you would rather use than rewrite from scratch! Getopt() and getopt_long() are frameworks written, debugged, and proven, that you just use. I don't have to "Hunt down" the actual code, I just use it!

    I don't want to spend vast amounts of time hard coding Command Line Argument options, and other non-option arguments, or end up with 175 lines of complicated code. How much work will it take to Add/Change/Delete some of your options, plus track down intermittent bugs? Very little when using getopt() or getopt_long()!

    Why do you consistently fight the excellent advise you are given by more experienced programmers? Some of us have been there, doen that, made mistakes and learned from those mistakes. Why ask for advice when it will just be ignored when we offer it??? You wonder why readers don't respond to many of your postings!!!

    getopt() may not be part of the C Standard, but is, "POSIX.1-2001, POSIX.1-2008, and POSIX.2"

    Please review the code examples in the man page link above.
    Actually no, I plan to do my own version of sprintfv and map a how bunch to it, I'm tired of PRIdMAX etc when in pedantic mode, only reason I haven't gotten to it already is because dealing with more pressing matters, and there is practically no effort to add new options, just add an if statement to ArgHasIssue(), it's job is to process the option and the values dedicated to it, for example "gcc -o a.out obj1.o obj2.o" would call ArgHasIssue( 1, 3, argv ), the function doesn't give a crap about checking for other options in the values, it just does a more thorough check on argv[1] to identify what it should do with that option and how many values are permitted for the option, ArgHadIssue() takes the same values and chucks out the error returned by ArgHasIssue(), ProcessArgv() is only supposed to detect the presence of any option, it does nothing beyond that, instead fobbing off the task of processing the options to ArgHasIssue() so in reality ProccessArgv() is unlikely to ever change now

  12. #12
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    Let's me look closely at this reply.

    Quote Originally Posted by awsdert View Post
    Sure that probably works but I like my method more,
    I can't help with that. But what I do know is anybody here can take those 52 lines, run it though their C compiler and have working code. That counts for something.


    it's easier to handle common errors...
    I don't think that is the case.

    ...and avoid copying memory unnecessarily.
    Where is that unnecessary memory copying? And processing command lines is a once-only thing, so efficiency isn't a real concern at all as far as I can tell?

    Plus it helps keep main() simpler,
    Nothing stops using a good design to hide make this only a handful of lines main():

    Code:
    #include <stdio.h>
    #include "user_opts.h"
    
    
    int main(int argc, char *argv[]) {
       struct user_opts opts;
       if(!opts_process_args(&opts, argc, argv)) {
          // opts_process_args is responsible for logging/displaying any issue
          return 1;
       }
       printf("Verbose  %i\n",opts.verbose);
       printf("Detailed %i\n",opts.detailed);
       printf("Path     %s\n",opts.path);
       return 0;
    }
    and with the amount of test code I currently have in main() for the glengine project I really do need a simpler main() function,
    "it helps keep main() simple" and "my main() is already too complex" in the same sentence? So your design techniques and ethos isn't really working out for you, but you refuse to adapt.

    I plan to move the code into another file later so that all argument handling has it's own dedicated file,
    As I said and shown. this can be done with that command line processing code - here's the header file for it:

    Code:
    #ifndef __USER_OPTS_H
    #define __USER_OPTS_H
    struct user_opts {
      int verbose;
      int detailed;
      char *path;
    };
    
    
    int opts_process_args(struct user_opts *opts, int argc, char *argv[]);
    #endif
    How much simpler an interface can you get?

    eventually I want have main only handle the initialisation & cleanup of objects that are to be passed around, argument handling does not belong directly in main() for that kind of plan.
    You are 100% wrong here. main() is the entry point to your code. An aspect of argument handling most definitely does belong in main(). Even if you very quickly contract it out to a sub-module it is "main" that ultimately deals with the logic to see if the user has provided acceptable inputs (unless your command line handler want to call exit(), I guess).

    Even with everything modularized, only three lines in a separate main() dedicated to command line argument handling it is still less then half the code.

    Code:
      14 main.c
      60 user_opts.c
      10 user_opts.h
      84 total
    Last edited by hamster_nz; 08-12-2021 at 04:49 PM.

  13. #13
    Registered User awsdert's Avatar
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    Quote Originally Posted by hamster_nz View Post
    I can't help with that. But what I do know is anybody here can take those 52 lines, run it though their C compiler and have working code. That counts for something.
    they can do so with mine too, ArgHasIssue() is only processing the arguments as soon as possible, opt*() appears to just dump it in a list like getenv() retrieves from
    Quote Originally Posted by hamster_nz View Post
    I don't think that is the case.
    Depends on viewpoint, I like to be able to get detailed information out of an error, that cannot be done when everything is handed of to some libraries function unless the function is specifically designed to take a callback that allows you to go find and print that information, from what I've seen the opt*() family does not provide that.
    Quote Originally Posted by hamster_nz View Post
    Where is that unnecessary memory copying? And processing command lines is a once-only thing, so efficiency isn't a real concern at all as far as I can tell?
    As previously mentioned from what I've seen the opt*() family appears to dump arguments and their values in a list, that can involve allocations, I don't personally see the need for that, better to just use the arguments & values as is
    Quote Originally Posted by hamster_nz View Post
    Nothing stops using a good design to hide make this only a handful of lines main():
    Guessing you meant to say "Nothing stopping a good design..", again that depends on how one wants to process those arguments to begin with.
    Quote Originally Posted by hamster_nz View Post
    "it helps keep main() simple" and "my main() is already too complex" in the same sentence? So your design techniques and ethos isn't really working out for you, but you refuse to adapt.
    I said SIMPLER, meaning the code was originally part of main, I just shifted it into it's own set of functions so I could find other code inside main quicker (of which I also plan to move after I'm done getting basic pngs to deflate correctly
    Quote Originally Posted by hamster_nz View Post
    As I said and shown. this can be done with that command line processing code - here's the header file for it:

    Code:
    #ifndef __USER_OPTS_H
    #define __USER_OPTS_H
    struct user_opts {
      int verbose;
      int detailed;
      char *path;
    };
    
    
    int opts_process_args(struct user_opts *opts, int argc, char *argv[]);
    #endif
    How much simpler an interface can you get?
    That's isolating all options, I would have to move them after, I prefer to put them where they're supposed to go from the outset
    Quote Originally Posted by hamster_nz View Post
    You are 100% wrong here. main() is the entry point to your code. An aspect of argument handling most definitely does belong in main(). Even if you very quickly contract it out to a sub-module it is "main" that ultimately deals with the logic to see if the user has provided acceptable inputs (unless your command line handler want to call exit(), I guess).
    No, I would have to add special error handling each time I need to add a return statment, I'd rather main just initialise needed objects, call ProcessArgs(), then call something like Main( Buffers ), then de-initialise everything before exiting, then Main() can just return an error code or 0, keeps exit procedures simple because most functions can just return a code and leave memory cleanup to main(), I prefer to design for minimal checks when cleaning up, here's an example of what I mean:
    Code:
    int main( int argc, char *argv[] )
    {
      int err;
      ALLOC Alloc = {0};
      BUFFERS Buffers = {0};
      CORE Core = {0};
     
      Core.Bufers = &Buffers;
      Buffers.Alloc = &Alloc;
      Alloc.errors = stderr;
      err = (ProcessArgs( &Core, argc, argv ) || Main( &Core ));
    
      EmptyBuffers( &Buffers );
      
      if( err )
      {
        ECHO( Alloc.errors, ECHO_ERR( Alloc.errors, err ) );
        return EXIT_FAILURE;
      }
      
      return EXIT_SUCCESS;
    }
    That's my goal, brutally simple

  14. #14
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    Quote Originally Posted by awsdert View Post
    they can do so with mine too,
    NO THEY CAN NOT.

    Nobody (not even the compiler) knows what ALLOC, BUFFER and CORE are and what they do. We only guess at what ECHO does, the code is almost opaque to everybody. Don't bother explaining them. I don't care - learning about them won't make my world richer.

    And no, you can't expected to pull whole random repos from random places to answer your question on a message board.

    Currently you do not really code in C. You code in some weird, self constructed dialect of C that nobody else speaks and if I am being very kind has minimal intrinsic merit over the basic language itself.

    You are like a friend who has decided to learn English through the teachings of Yoda in Star Wars. All the words are right, but the actual ideas are lost, confused and muddied.

    It's like if I asked you "what's wrong with this C code? why doesn't it compile":

    Code:
    int foo(int a) DEF
       WHILE(a > 0) DO
          printf("%i\n",a);
          DECREMENT(a);
       LOOP
    ENDDEF
    And then go on to argue that it is perfectly valid C - it is my better style of C - it is just that you don't have this header file:

    Code:
    #define IF(x)  if(x)
    #define THEN  {
    #define ENDIF }
    #define WHILE(x) while(x)
    #define DO {
    #define LOOP }
    #define DEF  {
    #define ENDDEF }
    #define DECREMENT(x) x--
    If you are honest with yourself even said as much yourself:
    Someone tell if this output makes sense to them in relation to the code below (start with bottom function - "ProcessArgv") it because it sure doesn't to me.
    You need to start writing idiomatic standard C, use the standard library, just use malloc() and free(), use assert(), and getopt(), just use the stdint.h types like uint8_t like the rest of us do. Don't keep putting everything in an needless wrappers and abstractions.

    Move to the C all your future co-workers will use, to the C all the projects you will contribute to will use, to the C you will have to use if you want people to collaborate with you.

    Sorry if this 'tough love' hurts, but it is my honest thoughts and feelings.
    Last edited by hamster_nz; 08-12-2021 at 07:12 PM.

  15. #15
    Registered User awsdert's Avatar
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    Quote Originally Posted by hamster_nz View Post
    NO THEY CAN NOT.

    Nobody (not even the compiler) knows what ALLOC, BUFFER and CORE are and what they do. We only guess at what ECHO does, the code is almost opaque to everybody. Don't bother explaining them. I don't care - learning about them won't make my world richer.

    And no, you can't expected to pull whole random repos from random places to answer your question on a message board.

    Currently you do not really code in C. You code in some weird, self constructed dialect of C that nobody else speaks and if I am being very kind has minimal intrinsic merit over the basic language itself.

    You are like a friend who has decided to learn English through the teachings of Yoda in Star Wars. All the words are right, but the actual ideas are lost, confused and muddied.

    It's like if I asked you "what's wrong with this C code? why doesn't it compile":

    Code:
    int foo(int a) DEF
       WHILE(a > 0) DO
          printf("%i\n",a);
          DECREMENT(a);
       LOOP
    ENDDEF
    And then go on to argue that it is perfectly valid C - it is my better style of C - it is just that you don't have this header file:

    Code:
    #define IF(x)  if(x)
    #define THEN  {
    #define ENDIF }
    #define WHILE(x) while(x)
    #define DO {
    #define LOOP }
    #define DEF  {
    #define ENDDEF }
    #define DECREMENT(x) x--
    If you are honest with yourself even said as much yourself:


    You need to start writing idiomatic standard C, use the standard library, just use malloc() and free(), use assert(), and getopt(), just use the stdint.h types like uint8_t like the rest of us do. Don't keep putting everything in an needless wrappers and abstractions.

    Move to the C all your future co-workers will use, to the C all the projects you will contribute to will use, to the C you will have to use if you want people to collaborate with you.

    Sorry if this 'tough love' hurts, but it is my honest thoughts and feelings.
    Your misunderstanding something fundamental, ArgHasIssue & ArgHadIssue are supposed to be custom, ie. rip out the contents fin favour of whatever option & accepted values you want, mine is just an example of what to do with them, ProcessArgv() on the other hand for the most part isn't supposed to change aside from ripping out the print statements which are there to verify what was getting through to where

    Quote Originally Posted by hamster_nz View Post
    Code:
       while(i != argc) {
         if(strncmp(argv[i], verbose_opt, strlen(verbose_opt))==0) {
             verbose = 1;
             if(argv[i][strlen(verbose_opt)] == '=')
               verbose = atoi(argv[i]+strlen(verbose_opt)+1);
             else if(argv[i][strlen(verbose_opt)] != '\0')
               break;
             i++;
         } else if(strncmp(argv[i], detailed_opt, strlen(detailed_opt))==0) {
             detailed = 1;
             if(argv[i][strlen(detailed_opt)] == '=')
               verbose = atoi(argv[i]+strlen(detailed_opt)+1);
             else if(argv[i][strlen(detailed_opt)] != '\0')
               break;
             i++;
         } else if(strcmp(argv[i],"-f")==0 && i != argc-1) {
             if(path)
                 break; // Specifed file name twice
             path = argv[i+1];
             i+=2;
         } else {
             break; // Option not expected
         }
       }
    Here's an example you gave that would be moved to ArgHasIssue() or in what I'm planning a bunch of callbacks that ArgHasIssue() would use upon confirming what option is being handed over from a list like this:
    Code:
    typedef struct _OPT
    {
      char const *opt;
      int (*use)( int a, int num, char *argv[] );
    } OPT;
    
    OPT options[] = 
    {
      { "--verbose", VerboseOptHasIssue },
      { "--detailed", DetailedOptHasIssue },
      { "-f", FileOptHasIssue },
    { NULL } };
    
    /* Poor example of what mak would use */
    int OptHasIssue( int a, int num, char *argv[] ) { setenv( argv[a], argv[a + num] ); return 0; }
    
    int ArgHasIssue( int a, int num, char *argv[] )
    {
      int i;
      for ( i = 0; options[i].opt; ++i )
      {
         OPT *o = &(options[i]);
         if ( strstr( argv[a], o->opt ) == argv[a] )
            return o->use( a, num, argv );
       }
      return OptHasIssue( a, num, argv );
    }
    Insisting on using implementation based APIs just because the rest of the world is using it is the equivalent of shooting oneself in the foot because you were told you'd only be walking only to then find out you have to swim in the sea, it does nothing but bring headaches, headaches I do not want, I'd rather develop code inspired by the implementation based "standards" and get a more reliable version of said standard then rely on the given implementations, while musl can probably help me with much of that, flexible argument handling is one that needs a new standard, the code I've given so far is not meant to be the new standard but a step in the direction of it, now as for why I say I would do a new version of sprintfv & co it is simply because I do not want the compiler complaining over every usage of "%zu", "%ju", etc, better to do a custom version with my own prefix and just follow the standard format specifiers given, that way I can just attach the header and source file of said set and peops can figure it out themselves when they say the include for it at the top of the code I post for it... or just do a global replace if they know their implementation will support the expected stuff. Eventually I want to move away from libc reliance altogether but that aim I will leave for the paw project of mine, where everything is prefixed with paw anyways, musl on the other hand doesn't have the luxury of a prefix so it has to force libc out whereas wih paw I can leave that as an optional tag along

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