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POWhy does fgetpos() return a negative offset?
 

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  1. POWhy does fgetpos() return a negative offset?
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    <p>When I am using <code>fgetpos(fp,&amp;pos)</code>, the call is setting <code>pos</code> to a negative value where <code>pos</code> is of type <code>fpos_t</code>. Can some one explain why this is happening?</p> <pre><code>#include&lt;stdio.h&gt; #include&lt;string.h&gt; #include&lt;stdlib.h&gt; #define TRUE 1 #define FALSE 0 #define MAX_TAG_LEN 50 char filename[1000] = "d:\\ire\\a.xml"; //extract each tag from the xml file int getTag(char * tag, FILE *fp) { //skip until a beginning of a next while(!feof(fp)) if((char)fgetc(fp) == '&lt;')break; if(!feof(fp)){ char temp[MAX_TAG_LEN]={0}; char *ptr; int len; fpos_t b; fgetpos(fp,&amp;b); // here the b is containing -ve values.....??? fread(temp,sizeof(char),MAX_TAG_LEN - 1,fp); temp[MAX_TAG_LEN-1] = 0; ptr = strchr(temp,'&gt;'); //search of ending tag bracket len = ptr - temp + 1; sprintf(tag,"&lt;%.*s",len,temp); //copy the tag printf("%s",tag); //print the tag b += len; //reset the position of file pointer to just after the tag character. fsetpos(fp,&amp;b); return TRUE; } else{ return FALSE; } } int main() { int ch; char tag[100]={0}; FILE *fp = fopen(filename,"r"); while(getTag(tag,fp)){ } fclose(fp); return 0; } </code></pre> <p>where a.xml is a very basic xml file</p> <pre><code>&lt;file&gt; &lt;page&gt; &lt;title&gt;AccessibleComputing&lt;/title&gt; &lt;id&gt;10&lt;/id&gt; &lt;redirect /&gt; &lt;revision&gt; &lt;id&gt;133452289&lt;/id&gt; &lt;timestamp&gt;2007-05-25T17:12:12Z&lt;/timestamp&gt; &lt;contributor&gt; &lt;username&gt;Gurch&lt;/username&gt; &lt;id&gt;241822&lt;/id&gt; &lt;/contributor&gt; &lt;minor /&gt; &lt;comment&gt;Revert edit(s) by [[Special:Contributions/Ngaiklin|Ngaiklin]] to last version by [[Special:Contributions/Rory096|Rory096]]&lt;/comment&gt; &lt;text xml:space="preserve"&gt;#REDIRECT [[Computer accessibility]] {{R from CamelCase}}&lt;/text&gt; &lt;/revision&gt; &lt;/page&gt; &lt;/file&gt; </code></pre> <p>The code is working for some xml files but for the above xml file it is stoping after printing the first tag.</p>
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    1. USVineel Kumar Reddy
    1. USVineel Kumar Reddy
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      1. POWhy does fgetpos() return a negative offset?
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      1. VTUpMod
    2. VO
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    1. COplease post the full code you are using to fpos
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      1. USAss3mbler
 

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