Parse string into argv/argc

Question

Is there a way in C to parse a piece of text and obtain values for argv and argc, as if the text had been passed to an application on the command line?

This doesn't have to work on Windows, just Linux - I also don't care about quoting of arguments.

Answer 1

I'm surprised nobody has provided the simplest answer using standard POSIX functionality:

http://www.opengroup.org/onlinepubs/9699919799/functions/wordexp.html

Answer 2

Here's my contribution. Its nice and short, but things to be wary of are:

• The use of strtok modifies the original "commandLine" string, replacing the spaces with \0 end-of-string delimeters
• argv[] ends up pointing into "commandLine", so don't modify it until you're finished with argv[].

The code:

enum { kMaxArgs = 64 };
int argc = 0;
char *argv[kMaxArgs];

char *p2 = strtok(commandLine, " ");
while (p2 && argc < kMaxArgs-1)
  {
    argv[argc++] = p2;
    p2 = strtok(0, " ");
  }
argv[argc] = 0;

You can now use argc and argv, or pass them to other functions declared like "foo(int argc, char **argv)".

Answer 3

If glib solution is overkill for your case you may consider coding one yourself.

Then you can:

• scan the string and count how many arguments there are (and you get your argc)
• allocate an array of char * (for your argv)
• rescan the string, assign the pointers in the allocated array and replace spaces with '\0' (if you can't modify the string containing the arguments, you should duplicate it).
• don't forget to free what you have allocated!

The diagram below should clarify (hopefully):

             aa bbb ccc "dd d" ee         <- original string

             aa0bbb0ccc00dd d00ee0        <- transformed string
             |  |   |    |     |
   argv[0] __/  /   /    /     /
   argv[1] ____/   /    /     /
   argv[2] _______/    /     /
   argv[3] ___________/     /
   argv[4] ________________/ 

A possible API could be:

    char **parseargs(char *arguments, int *argc);
    void   freeparsedargs(char **argv);

You will need additional considerations to implement freeparsedargs() safely.

If your string is very long and you don't want to scan twice you may consider alteranatives like allocating more elements for the argv arrays (and reallocating if needed).

EDIT: Proposed solution (desn't handle quoted argument).

    #include <stdio.h>

    static int setargs(char *args, char **argv)
    {
       int count = 0;

       while (isspace(*args)) ++args;
       while (*args) {
         if (argv) argv[count] = args;
         while (*args && !isspace(*args)) ++args;
         if (argv && *args) *args++ = '\0';
         while (isspace(*args)) ++args;
         count++;
       }
       return count;
    }

    char **parsedargs(char *args, int *argc)
    {
       char **argv = NULL;
       int    argn = 0;

       if (args && *args
        && (args = strdup(args))
        && (argn = setargs(args,NULL))
        && (argv = malloc((argn+1) * sizeof(char *)))) {
          *argv++ = args;
          argn = setargs(args,argv);
       }

       if (args && !argv) free(args);

       *argc = argn;
       return argv;
    }

    void freeparsedargs(char **argv)
    {
      if (argv) {
        free(argv[-1]);
        free(argv-1);
      } 
    }

    int main(int argc, char *argv[])
    {
      int i;
      char **av;
      int ac;
      char *as = NULL;

      if (argc > 1) as = argv[1];

      av = parsedargs(as,&ac);
      printf("== %d\n",ac);
      for (i = 0; i < ac; i++)
        printf("[%s]\n",av[i]);

      freeparsedargs(av);
      exit(0);
    }

Answer 4

The always-wonderful glib has g_shell_parse_args() which sounds like what you're after.

If you're not interested in even quoting, this might be overkill. All you need to do is tokenize, using whitespace as a token character. Writing a simple routine to do that shouldn't take long, really.

If you're not super-stingy on memory, doing it in one pass without reallocations should be easy; just assume a worst-case of every second character being a space, thus assuming a string of n characters contains at most (n + 1) / 2 arguments, and (of course) at most n bytes of argument text (excluding terminators).

Answer 5

Here's a solution for both Windows and Unix (tested on Linux, OSX and Windows). Tested with Valgrind and Dr. Memory.

It uses wordexp for POSIX systems, and CommandLineToArgvW for Windows.

Note that for the Windows solution, most of the code is converting between char ** and wchar_t ** with the beautiful Win32 API, since there is no CommandLineToArgvA available (ANSI-version).

#ifdef _WIN32
#include <windows.h>
#else
#include <wordexp.h>
#endif

char **split_commandline(const char *cmdline, int *argc)
{
    int i;
    char **argv = NULL;
    assert(argc);

    if (!cmdline)
    {
        return NULL;
    }

    // Posix.
    #ifndef _WIN32
    {
        wordexp_t p;

        // Note! This expands shell variables.
        if (wordexp(cmdline, &p, 0))
        {
            return NULL;
        }

        *argc = p.we_wordc;

        if (!(argv = calloc(*argc, sizeof(char *))))
        {
            goto fail;
        }

        for (i = 0; i < p.we_wordc; i++)
        {
            if (!(argv[i] = strdup(p.we_wordv[i])))
            {
                goto fail;
            }
        }

        wordfree(&p);

        return argv;
    fail:
        wordfree(&p);
    }
    #else // WIN32
    {
        wchar_t **wargs = NULL;
        size_t needed = 0;
        wchar_t *cmdlinew = NULL;
        size_t len = strlen(cmdline) + 1;

        if (!(cmdlinew = calloc(len, sizeof(wchar_t))))
            goto fail;

        if (!MultiByteToWideChar(CP_ACP, 0, cmdline, -1, cmdlinew, len))
            goto fail;

        if (!(wargs = CommandLineToArgvW(cmdlinew, argc)))
            goto fail;

        if (!(argv = calloc(*argc, sizeof(char *))))
            goto fail;

        // Convert from wchar_t * to ANSI char *
        for (i = 0; i < *argc; i++)
        {
            // Get the size needed for the target buffer.
            // CP_ACP = Ansi Codepage.
            needed = WideCharToMultiByte(CP_ACP, 0, wargs[i], -1,
                                        NULL, 0, NULL, NULL);

            if (!(argv[i] = malloc(needed)))
                goto fail;

            // Do the conversion.
            needed = WideCharToMultiByte(CP_ACP, 0, wargs[i], -1,
                                        argv[i], needed, NULL, NULL);
        }

        if (wargs) LocalFree(wargs);
        if (cmdlinew) free(cmdlinew);
        return argv;

    fail:
        if (wargs) LocalFree(wargs);
        if (cmdlinew) free(cmdlinew);
    }
    #endif // WIN32

    if (argv)
    {
        for (i = 0; i < *argc; i++)
        {
            if (argv[i])
            {
                free(argv[i]);
            }
        }

        free(argv);
    }

    return NULL;
}

Answer 6

I just did this for an embedded project in plain C, where I have a little CLI that parses serial port input and executes a limited set of commands with the parameters.

This is probably not the neatest, but as small and efficient as I could get it:

int makeargs(char *args, int *argc, char ***aa) {
    char *buf = strdup(args);
    int c = 1;
    char *delim;
    char **argv = calloc(c, sizeof (char *));

    argv[0] = buf;

    while (delim = strchr(argv[c - 1], ' ')) {
        argv = realloc(argv, (c + 1) * sizeof (char *));
        argv[c] = delim + 1;
        *delim = 0x00;
        c++;
    }

    *argc = c;
    *aa = argv;

    return c;
}

to test:

int main(void) {
    char **myargs;
    int argc;

    int numargs = makeargs("Hello world, this is a test", &argc, &myargs);
    while (numargs) {
        printf("%s\r\n", myargs[argc - numargs--]);
    };

    return (EXIT_SUCCESS);
}

Answer 7

Matt Peitrek's LIBTINYC has a module called argcargv.cpp that takes a string and parses it out to the argument array taking quoted arguments into account. Note that it's Windows-specific, but it's pretty simple so should be easy to move to whatever platform you want.

Answer 8

I ended up writing a function to do this myself, I don't think its very good but it works for my purposes - feel free to suggest improvements for anyone else who needs this in the future:

void parseCommandLine(char* cmdLineTxt, char*** argv, int* argc){
    int count = 1;

    char *cmdLineCopy = strdupa(cmdLineTxt);
    char* match = strtok(cmdLineCopy, " ");
 // First, count the number of arguments
    while(match != NULL){
        count++;
        match = strtok(NULL, " ");
    }

    *argv = malloc(sizeof(char*) * (count+1));
    (*argv)[count] = 0;
    **argv = strdup("test"); // The program name would normally go in here

    if (count > 1){
        int i=1;
        cmdLineCopy = strdupa(cmdLineTxt);
        match = strtok(cmdLineCopy, " ");
        do{
            (*argv)[i++] = strdup(match);
            match = strtok(NULL, " ");
        } while(match != NULL);
     }

    *argc = count;
}

Answer 9

Consider yet another implementation. Run.

#include <cctype>  // <ctype.h>  for isspace()

/** 
 * Parse out the next non-space word from a string.
 * @note No nullptr protection
 * @param str  [IN]   Pointer to pointer to the string. Nested pointer to string will be changed.
 * @param word [OUT]  Pointer to pointer of next word. To be filled.
 * @return  pointer to string - current cursor. Check it for '\0' to stop calling this function   
 */
static char* splitArgv(char **str, char **word)
{
    constexpr char QUOTE = '\'';
    bool inquotes = false;

    // optimization
    if( **str == 0 )
        return NULL;

    // Skip leading spaces.
    while (**str && isspace(**str)) 
        (*str)++;

    if( **str == '\0')
        return NULL;

    // Phrase in quotes is one arg
    if( **str == QUOTE ){
        (*str)++;
        inquotes = true;
    }

    // Set phrase begining
    *word = *str;

    // Skip all chars if in quotes
    if( inquotes ){
        while( **str && **str!=QUOTE )
            (*str)++;
        //if( **str!= QUOTE )
    }else{
        // Skip non-space characters.
        while( **str && !isspace(**str) )
            (*str)++;
    }
    // Null terminate the phrase and set `str` pointer to next symbol
    if(**str)
        *(*str)++ = '\0';

    return *str;
}


/// To support standart convetion last `argv[argc]` will be set to `NULL`
///\param[IN]  str : Input string. Will be changed - splitted to substrings
///\param[IN]  argc_MAX : Maximum a rgc, in other words size of input array \p argv
///\param[OUT] argc : Number of arguments to be filled
///\param[OUT] argv : Array of c-string pointers to be filled. All of these strings are substrings of \p str
///\return Pointer to the rest of string. Check if for '\0' and know if there is still something to parse. \
///        If result !='\0' then \p argc_MAX is too small to parse all. 
char* parseStrToArgcArgvInsitu( char *str, const int argc_MAX, int *argc, char* argv[] )
{
    *argc = 0;
    while( *argc<argc_MAX-1  &&  splitArgv(&str, &argv[*argc]) ){
        ++(*argc);
        if( *str == '\0' )
            break;
    }
    argv[*argc] = nullptr;
    return str;
};

Usage code

#include <iostream>
using namespace std;

void parseAndPrintOneString(char *input)
{
    constexpr size_t argc_MAX = 5;
    char* v[argc_MAX] = {0};
    int c=0;

    char* rest = parseStrToArgcArgvInsitu(input,argc_MAX,&c,v);
    if( *rest!='\0' )  // or more clear `strlen(rest)==0` but not efficient
        cout<<"There is still something to parse. argc_MAX is too small."<<endl;

    cout << "argc : "<< c << endl;
    for( int i=0; i<c; i++ )
        cout<<"argv["<<i<<"] : "<<v[i] <<endl;
    /*//or condition is `v[i]`
    for( int i=0; v[i]; i++ )
        cout<<"argv["<<i<<"] : "<<v[i] <<endl;*/
}



int main(int argc, char* argv[])
{
    char inputs[][500] ={
              "Just another TEST\r\n"
            , "  Hello my world 'in quotes' \t !"
            , "./hi 'Less is more'"
            , "Very long line with \"double quotes\" should be parsed several times if argv[] buffer is small"
            , "   \t\f \r\n"
    };

    for( int i=0; i<5; ++i ){
        cout<<"Parsing line \""<<inputs[i]<<"\":"<<endl;
        parseAndPrintOneString(inputs[i]);
        cout<<endl;
    }
}

Output:

Parsing line "Just another TEST\r\n":
argc : 3
argv[0] : Just
argv[1] : another
argv[2] : TEST

Parsing line "  Hello my world 'in quotes'   !":
There is still something to parse. argc_MAX is too small.
argc : 4
argv[0] : Hello
argv[1] : my
argv[2] : world
argv[3] : in quotes

Parsing line "./hi 'Less is more'":
argc : 2
argv[0] : ./hi
argv[1] : Less is more

Parsing line "Very long line with "double quotes" should be parsed several times if argv[] buffer is small":
There is still something to parse. argc_MAX is too small.
argc : 4
argv[0] : Very
argv[1] : long
argv[2] : line
argv[3] : with

Parsing line "       

":
argc : 0

Answer 10

Solution for those that don't want to use dynamic memory allocation (E.g. embedded)

I written tokenise_to_argc_argv() for an embedded project, which uses strtok_r() as the basis for tokenising a command string into argc and argv form. Unlike most answers here, I usually allocate memory statically. Thus my implementation assumes that you have an upper bound of argv_length. For most typical embedded applications, this is more than enough. I included example code below as well so you can quickly use it.

int tokenise_to_argc_argv(
        char     *buffer,     ///< In/Out : Modifiable String Buffer To Tokenise
        int      *argc,       ///< Out    : Argument Count
        char     *argv[],     ///< Out    : Argument String Vector Array
        const int argv_length ///< In     : Maximum Count For `*argv[]`
      )
{ /* Tokenise string buffer into argc and argv format (req: string.h) */
  int i = 0;
  for (i = 0 ; i < argv_length ; i++)
  { /* Fill argv via strtok_r() */
    if ( NULL == (argv[i] = strtok_r( NULL , " ", &buffer)) ) break;
  }
  *argc = i;
  return i; // Argument Count
}

Note:

• The provided character buffer must be modifiable (as strtok_r() inserts \0 into the buffer to delimitate string tokens).
• strtok_r in this function is currently using " " space character as the only deliminator. This emulates the behaviour main(int argc, char *argv[]) in typical commandline interfaces.
• This function does not use malloc or calloc, instead you will have to allocate the argv array separately, and supply the length of argv explicitly. This is because I intend to use this in embedded devices and thus would rather allocate it manually.
• strtok_r() is used because it is threadsafe (Since strtok() uses an internal static pointer). Also it is part of the standard C library string.h thus is very portable.

Below are the demonstration code as well as it's output. In addition, this shows that tokenise_to_argc_argv() can handle most string cases and thus has been tested. Also this function does not rely on malloc or calloc and thus is suitable for embedded usage (after using stdint.h types).

---

Demonstration Code

/*******************************************************************************
  Tokenise String Buffer To Argc and Argv Style Format
  Brian Khuu 2017
*******************************************************************************/
#include <stdio.h>  // printf()
#include <ctype.h>  // isprint()
#include <string.h> // strtok_r()

/**-----------------------------------------------------------------------------
  @brief Tokenise a string buffer into argc and argv format

  Tokenise string buffer to argc and argv form via strtok_r()
  Warning: Using strtok_r will modify the string buffer

  Returns: Number of tokens extracted

------------------------------------------------------------------------------*/
int tokenise_to_argc_argv(
        char     *buffer,     ///< In/Out : Modifiable String Buffer To Tokenise
        int      *argc,       ///< Out    : Argument Count
        char     *argv[],     ///< Out    : Argument String Vector Array
        const int argv_length ///< In     : Maximum Count For `*argv[]`
      )
{ /* Tokenise string buffer into argc and argv format (req: string.h) */
  int i = 0;
  for (i = 0 ; i < argv_length ; i++)
  { /* Fill argv via strtok_r() */
    if ( NULL == (argv[i] = strtok_r( NULL, " ", &buffer)) ) break;
  }
  *argc = i;
  return i; // Argument Count
}

/*******************************************************************************
  Demonstration of tokenise_to_argc_argv()
*******************************************************************************/

static void print_buffer(char *buffer, int size);
static void print_argc_argv(int argc, char *argv[]);
static void demonstrate_tokenise_to_argc_argv(char buffer[], int buffer_size);

int main(void)
{ /* This shows various string examples */
  printf("# `tokenise_to_argc_argv()` Examples\n");
  { printf("## Case0: Normal\n");
    char  buffer[] = "tokenising example";
    demonstrate_tokenise_to_argc_argv(buffer, sizeof(buffer));
  }
  { printf("## Case1: Empty String\n");
    char  buffer[] = "";
    demonstrate_tokenise_to_argc_argv(buffer, sizeof(buffer));
  }
  { printf("## Case2: Extra Space\n");
    char  buffer[] = "extra  space here";
    demonstrate_tokenise_to_argc_argv(buffer, sizeof(buffer));
  }
  { printf("## Case3: One Word String\n");
    char  buffer[] = "one-word";
    demonstrate_tokenise_to_argc_argv(buffer, sizeof(buffer));
  }
}

static void demonstrate_tokenise_to_argc_argv(char buffer[], int buffer_size)
{ /* This demonstrates usage of tokenise_to_argc_argv */
  int   argc     = 0;
  char *argv[10] = {0};

  printf("* **Initial State**\n");
  print_buffer(buffer, buffer_size);

  /* Tokenise Command Buffer */
  tokenise_to_argc_argv(buffer, &argc, argv, sizeof(argv));

  printf("* **After Tokenizing**\n");
  print_buffer(buffer, buffer_size);
  print_argc_argv(argc,argv);
  printf("\n\n");
}

static void print_buffer(char *buffer, int size)
{
  printf(" - Buffer Content `");
  for (int i = 0 ; i < size; i++) printf("%c",isprint(buffer[i])?buffer[i]:'0');
  printf("` | HEX: ");
  for (int i = 0 ; i < size; i++) printf("%02X ", buffer[i]);
  printf("\n");
}

static void print_argc_argv(int argc, char *argv[])
{ /* This displays the content of argc and argv */
  printf("* **Argv content** (argc = %d): %s\n", argc, argc ? "":"Argv Is Empty");
  for (int i = 0 ; i < argc ; i++) printf(" - `argv[%d]` = `%s`\n", i, argv[i]);
}

---

Output

tokenise_to_argc_argv() Examples

Case0: Normal

• Initial State
  • Buffer Content tokenising example0 | HEX: 74 6F 6B 65 6E 69 73 69 6E 67 20 65 78 61 6D 70 6C 65 00
• After Tokenizing
  • Buffer Content tokenising0example0 | HEX: 74 6F 6B 65 6E 69 73 69 6E 67 00 65 78 61 6D 70 6C 65 00
• Argv content (argc = 2):
  • argv[0] = tokenising
  • argv[1] = example

Case1: Empty String

• Initial State
  • Buffer Content 0 | HEX: 00
• After Tokenizing
  • Buffer Content 0 | HEX: 00
• Argv content (argc = 0): Argv Is Empty

Case2: Extra Space

• Initial State
  • Buffer Content extra space here0 | HEX: 65 78 74 72 61 20 20 73 70 61 63 65 20 68 65 72 65 00
• After Tokenizing
  • Buffer Content extra0 space0here0 | HEX: 65 78 74 72 61 00 20 73 70 61 63 65 00 68 65 72 65 00
• Argv content (argc = 3):
  • argv[0] = extra
  • argv[1] = space
  • argv[2] = here

Case3: One Word String

• Initial State
  • Buffer Content one-word0 | HEX: 6F 6E 65 2D 77 6F 72 64 00
• After Tokenizing
  • Buffer Content one-word0 | HEX: 6F 6E 65 2D 77 6F 72 64 00
• Argv content (argc = 1):
  • argv[0] = one-word

---

Missing string.h or strtok_r() in your toolchain somehow?

If for some reason your toolchain does not have strtok_r(). You can use this simplified version of strtok_r(). It is a modified version of the GNU C implementation of strtok_r(), but simplified to only support space character.

To use this, just place it on top of tokenise_to_argc_argv() then replace strtok_r( NULL, " ", &buffer) with strtok_space(&buffer)

/**-----------------------------------------------------------------------------
  @brief Simplied space deliminated only version of strtok_r()

  - save_ptr : In/Out pointer to a string. This pointer is incremented by this
                function to find and mark the token boundry via a `\0` marker.
                It is also used by this function to find mutiple other tokens
                via repeated calls.

  Returns:
    - NULL  : No token found
    - pointer to start of a discovered token

------------------------------------------------------------------------------*/
char * strtok_space(char **save_ptr)
{ /* strtok_space is slightly modified from GNU C Library `strtok_r()`  implementation. 
      Thus this function is also licenced as GNU Lesser General Public License*/
  char *start = *save_ptr;
  char *end = 0;

  if (*start == '\0') {
    *save_ptr = start;
    return NULL;
  }

  /* Scan leading delimiters.  */
  while(*start == ' ') start++;
  if (*start == '\0') {
    *save_ptr = start;
    return NULL;
  }

  /* Find the end of the token.  */
  end = start;
  while((*end != '\0') && (*end != ' ')) end++;
  if (*end == '\0') {
    *save_ptr = end;
    return start;
  }

  /* Terminate the token and make *SAVE_PTR point past it.  */
  *end = '\0';
  *save_ptr = end + 1;
  return start;
}

Answer 11

This one I wrote also considers quotes (but not nested)

Feel free to contribute.

/*
Tokenize string considering also quotes.
By Zibri <zibri AT zibri DOT org>
https://github.com/Zibri/tokenize
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>

int main(int argc, char *argv[])
{
  char *str1, *token;
  int j;
  char *qstart = NULL;
  bool quoted = false;

  if (argc != 2) {
    fprintf(stderr, "Usage: %s string\n", argv[0]);
    exit(EXIT_FAILURE);
  }

  for (j = 1, str1 = argv[1];; j++, str1 = NULL) {
    token = strtok(str1, " ");
    if (token == NULL)
      break;
    if ((token[0] == 0x27) || (token[0] == 0x22)) {
      qstart = token + 1;
      quoted = true;
    }
    if ((token[strlen(token) - 1] == 0x27) || (token[strlen(token) - 1] == 0x22)) {
      quoted = false;
      token[strlen(token) - 1] = 0;
      printf("%d: %s\n", j, qstart);
    } else {
      if (quoted) {
        token[strlen(token)] = 0x20;
        j--;
      } else
        printf("%d: %s\n", j, token);
    }
  }

  if (quoted) {
    fprintf(stderr, "String quoting error\n");
    return EXIT_FAILURE;
  } else
    return EXIT_SUCCESS;
}

Example output:

$ ./tokenize "1 2 3 '4 5 6' 7 8 \"test abc\" 10 11"
1: 1
2: 2
3: 3
4: 4 5 6
5: 7
6: 8
7: test abc
8: 10
9: 11

Answer 12

My project requires breaking a string into argc and argv.

Found a pretty excellent code of Torek. But it alters the input buffer so I made some modifications to fit my needs.

I just put a little bit more to handle quote mixing when input in the command line so the behavior is more (not completely) like Linux Shell.

Note: This function doesn't edit the original string, so you can reuse the input buffer (error report,etc).

void remove_quote(char* input){
   //Implementing yourself to remove quotes so it would be completely like Linux shell
}
size_t cmd_param_split(char *buffer, char *argv[], size_t argv_max_size)
{
    char *p, *start_of_word;
    int c, i;
    enum states { DULL=0, IN_WORD, IN_STRING, QUOTE_DOUBLE,QUOTE_SINGLE } state = DULL;
    size_t argc = 0;
    int quote = 0;
    for (p = buffer; argc < argv_max_size && *p != '\0'; p++) {
        c = (unsigned char) *p;
        printf("processing %c, state = %d\n", c,state);
        switch (state) {
        case DULL:
            if (isspace(c)) {
                continue;
            }

            if (c == '"' ||c == '\'') {
                quote = c;
                state = IN_STRING;
                start_of_word = p + 1;
                continue;
            }
            state = IN_WORD;
            start_of_word = p;
            continue;

        case IN_STRING:
            if (c == '"' || c == '\'') {
                if (c!=quote)
                    continue;
                else
                    quote = 0;
                strncpy(argv[argc],start_of_word, p - start_of_word);
                remove_quote(argv[argc]);
                argc++;
                state = DULL;
            }
            continue;

        case IN_WORD:
            if(quote==0 && (c == '\"' ||c == '\''))
                quote = c;
            else if (quote == c)
                    quote = 0;

            if (isspace(c) && quote==0) {
                strncpy(argv[argc],start_of_word, p - start_of_word);
                remove_quote(argv[argc]);
                argc++;
                state = DULL;
            }
            continue;
        }
    }

    if (state != DULL && argc < argv_max_size){
        strncpy(argv[argc],start_of_word, p - start_of_word);
        remove_quote(argv[argc]);
        argc++;
    }

    if (quote){
        printf("WARNING: Quote is unbalanced. This could lead to unwanted-behavior\n");
        for(i = 0;i<argc;i++)
            printf("arg %d = [%s]\n",i,argv[i]);
        printf("Original buffer: [%s]\n",buffer);
    }
    return argc;
}

int main()
{
    int i=0;
    int argc;
    char* argv[64];
    for(i=0;i<64;i++){
        argv[i] = malloc(256);
        memset(argv[i],0x0,256);
    }
     char* buffer="1 2 3 \'3 4\"567\' \"bol\'obala\" 2x2=\"foo\"";
    argc = cmd_param_split(buffer,argv,64);
    for(i = 0;i<argc;i++)
        printf("arg %d = [%s]\n",i,argv[i]);

    return 0;
}

Tested with below strings

 1. "1 2 3 \'3 4\"567\' \"bol\'obala\" 2x2=\"foo\""
   arg 0 = [1]
   arg 1 = [2]
   arg 2 = [3]
   arg 3 = [3 4"567]
   arg 4 = [bol'obala]
   arg 5 = [2x2="foo"]
 2. "./foo bar=\"Hanoi HoChiMinh\" exp='foo123 \"boo111' mixquote \"hanoi \'s\""
   arg 0 = [./foo]
   arg 1 = [bar="Hanoi HoChiMinh"]
   arg 2 = [exp='foo123 "boo111']
   arg 3 = [mixquote]
   arg 4 = [hanoi 's]

---

However, Linux shell would remove quotes, even in mixed case, as below when running from cmd line, tested in a RaspberryPi.

./foo bar="Hanoi HoChiMinh" exp='foo123 "boo111' mixquote "hanoi 's"
   arg 0 = [./foo]
   arg 1 = [bar=Hanoi HoChiMinh]
   arg 2 = [exp=foo123 "boo111]
   arg 3 = [mixquote]
   arg 4 = [hanoi 's]

So if you really want to mimic the whole Linux shell's behavior, just put a little bit more effort into removing quotes remove_quote() function as I leave blank above.

Answer 13

Unfortunately C++ but for others which might search for this kind of library i recommend:

ParamContainer - easy-to-use command-line parameter parser

Really small and really easy.

p.addParam("long-name", 'n', ParamContainer::regular, 
           "parameter description", "default_value");  

programname --long-name=value

cout << p["long-name"];
>> value

From my experience:

• very useful and simple
• stable on production
• well tested (by me)