Hi, I'm writting a text editor in C, and I have a problem.
I isolated the problem to the next simple program:
first, I work with bin files,and when writting to the file or reading,
it's by Str[73].
suppose that we prepared a file with three strings in it,the length of each is 73. now see this program:
void main()
{
FILE *fp;
char Str[73];

fp=fopen("FilePath","r+b");
fread(Str,sizeof(char),73,fp);
fseek(fp,-73L,SEEK_CUR); //return to the beginning of FirstLine
fwrite(Str,sizeof(char),73,fp);
fread(Str,sizeof(char),73,fp); //fail
fread(Str,sizeof(char),73,fp); //fail
fclose(fp);
}
now, I've discovered that putting fseek(fp,ftell(fp),SEEK_SET)
after the fwrite solves the problem.
if anyone knows info that can be help,I will be glade to here.
thx,
gambit

and sorry for my bad english

: Hi, I'm writting a text editor in C, and I have a problem.
: I isolated the problem to the next simple program:
: first, I work with bin files,and when writting to the file or reading,
: it's by Str[73].
: suppose that we prepared a file with three strings in it,the length of each is 73. now see this program:
: void main()
: {
: FILE *fp;
: char Str[73];
:
: fp=fopen("FilePath","r+b");
: fread(Str,sizeof(char),73,fp);
: fseek(fp,-73L,SEEK_CUR); //return to the beginning of FirstLine
: fwrite(Str,sizeof(char),73,fp);
: fread(Str,sizeof(char),73,fp); //fail
: fread(Str,sizeof(char),73,fp); //fail
: fclose(fp);
: }
: now, I've discovered that putting fseek(fp,ftell(fp),SEEK_SET)
: after the fwrite solves the problem.
: if anyone knows info that can be help,I will be glade to here.

An explicit call to either fseek() or fflush() is required between reads and writes in update ('+') mode. Read Question 12.30 in the C FAQ (second link in my signature) for more info.


: thx,
: gambit
:
: and sorry for my bad english

Your English is fine! :)


HTH,
Will
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