sscanf in MQX3.8.1 is not working correctly

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sscanf in MQX3.8.1 is not working correctly

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David_Wu
Contributor III

I have a case for sscanf that could not handle all the formats:

rc = sscanf(buf, "sig:%s\ncallid:%s\ncallname:%s\ngroup:%d\npgtype:%d\n",

(char *) (&parms->sig), (char *) (&parms->callid),

(char *) (&parms->callname),&parms->group_num,(&parms->msg_type));

 

what's inside the buf:

"sig:Arc621\ncallid:anonymous\ncallname:Anonymous\ngroup:2\npgtype:2\n"

 

The matching failed after the first "%d" - the issue in sscanf is:

  - A: the next character in format is '\n' - which is not treated as a white space (only blank and '\t' are treated )

  - B: the next character in input line is '\n' - which is a white space so it is thrown away then read next non-white space which is 'p' in the above example.

A and B did not match so the function sscanf returned without trying to match others.

 

I have a tempory work around is all white spaces are treated same in

_io_scanline_format_ignore_white_space, _io_scanline_ignore_white_space, and _io_scanline as well.

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4 Replies

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c0170
Senior Contributor III

Hi David_Wu,

 

first of all, this is snapped from  _io_sscanf function:

 

   va_start(ap, format_ptr);
   result = _io_scanline(str_ptr, (char _PTR_)format_ptr, ap);
   va_end(ap);

 

It calls _io_scanline. How come your problem does not appear with _io_scanline ?

 

Regards,

MartinK

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David_Wu
Contributor III

Hi MartinK,

 

My problem is exactly happended in  _io_scanline(). And the fix is also in  _io_scanline() and

_io_scanline_format_ignore_white_space().

 

char _io_scanline_format_ignore_white_space

   (     

/* [IN/OUT] the address of the string pointer */     

registerchar _PTR_ _PTR_ s_ptr,     

/* [OUT] the number of characters skipped */     

register_mqx_uint _PTR_  count

   )

{

/* Body */  

registerchar c;  

   *count = 0;

   c = **s_ptr;

 

//while (  (c == ' ') || (c == '\t') ) {//WMQ change - ignore all white spaces  

while (  (c == ' ') || (c == '\t') || (c == '\n') || (c == '\r') ||  (c =='\v') || (c == '\f') ) {

      c = *(++*s_ptr);

      (*count)++;

   }

/* Endwhile */  

return (c); 

}

/* Endbody */

 

 

_mqx_int  _io_scanline

   (  

/* [IN] the input line of ascii data*/     

char    _PTR_ line_ptr,     

/* [IN] fmt first points to the format string */     

char    _PTR_ format,      

/* [IN] the list of parameters */     

va_list       args_ptr

   )

{

/* Body */           

char       suppress_field;  

register_mqx_int   c;  

register_mqx_uint  n;           

char _PTR_ sptr = NULL;           

_mqx_int   sign;           

uint_32    val;           

_mqx_int   width;           

_mqx_int   numtype;  /* used to indicate bit size of argument */  

register_mqx_int   number_of_chars;           

_mqx_uint  temp;           

_mqx_uint  base;           

pointer    tmp_ptr;

#if MQX_INCLUDE_FLOATING_POINT_IO

double     dnum;

#endif

  

   n = 0;

   number_of_chars = 0;

  

while ((c = *format++) != 0) { 

      width = 0; 

    /*

      ** skip white space in format string, and any in input line

      */

     

//if ( (c == ' ') || (c == '\t') ) { //WMQ change - ignore all white spaces

if ( (c == ' ') || (c == '\t') || (c == '\n') || (c == '\r') ||  (c =='\v') || (c == '\f')) {        

if ( ! _io_scanline_format_ignore_white_space(             (

char _PTR_ _PTR_)&format, &temp ) ) {

           

......

109 Views
BielikM
Contributor III

Hi David_Wu,

Your fix has been integrated to MQX and will be available in MQX 4.0.2 release.

Thank you.

Regard

Martin

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c0170
Senior Contributor III

Hello David_Wu,

 

thank you for sharing your fix and reporting the problem ! It has been reported to the team :smileywink:

 

Regards,

MartinK

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