problem in reading file using fread


 
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# 1  
Old 10-28-2006
MySQL problem in reading file using fread

Hi All,

These are the two ways i tried to read file but i getting work with second one not with the first.

char buf[2000]; // Defining space for buf
ctrlfnum = fopen(filename_arr.control_fname,"r");

1) n = fread(buf,sizeof(buf),1,ctrlfnum); ============== (not works)
2) n = fread(buf,1000,1,ctrlfnum); ================== (Works)

NOTE : i'm using HP-UX C++.

Awaiting reply. Thanks in advance.

Thanks
# 2  
Old 10-28-2006
sizeof(a pointer to something) = size of a pointer variable, = 4 on a 32 bit machine.
sizeof(buf) is likely 4, not 1000.
# 3  
Old 10-30-2006
Thanks man,, I got what are yoy saying ...Thanks a lot ..

Can you please suggest can i make it works by fread .

Thanks in advance ,
Arun Kumar
# 4  
Old 10-30-2006
You need to have a way to know the maximum size of buf.
Try something global like a define.

Code:
#define REC_SZ 1000
......
int foo()
{
    char buf[REC_SZ]={0x0};
    bar(buf);
}

char *bar(char *buf)
{
.............
     fread(buf,REC_SZ,1,ctrlfnum); 

     return *buf;
}

# 5  
Old 10-30-2006
Quote:
Originally Posted by jim mcnamara
sizeof(a pointer to something) = size of a pointer variable, = 4 on a 32 bit machine.
sizeof(buf) is likely 4, not 1000.
char *buf;
sizeof(buf) => 4

char buf[2000];
sizeof(buf) => 2000

Regards
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