A simple question about a function

[Xiaoshen Li]

Dear All,

I am puzzled by how to use strtod(). I have pasted its man page below. I
don't understand what char **endptr is and why it is needed there.

Thank you very much.



STRTOD(3) Library functions
STRTOD(3)

NAME
strtod, strtof, strtold - convert ASCII string to floating point
number

SYNOPSIS
#include <stdlib.h>

double strtod(const char *nptr, char **endptr);
float strtof(const char *nptr, char **endptr);
long double strtold(const char *nptr, char **endptr);

DESCRIPTION
The strtod, strtof, and strtold functions convert the initial
portion of the string pointed to by nptr to double,
float, and long double representation, respectively.

 

[Xiaoshen Li]

I found the solution. Sorry for bothering.

endptr will point to the string(==pointer to a char array)

 

[Jordan Abel]

Dear All,

I am puzzled by how to use strtod(). I have pasted its man page below. I
don't understand what char **endptr is and why it is needed there.

Thank you very much.



STRTOD(3) Library functions STRTOD(3)

NAME
strtod, strtof, strtold - convert ASCII string to floating
point number

SYNOPSIS
#include <stdlib.h>

double strtod(const char *nptr, char **endptr);
float strtof(const char *nptr, char **endptr);
long double strtold(const char *nptr, char **endptr);

DESCRIPTION
The strtod, strtof, and strtold functions convert the
initial portion of the string pointed to by nptr to double,
float, and long double representation, respectively.

If that's the whole manpage, then you have a crappy manpage.

An exerpt from my manpage:

 

[Michael Mair]

Please do not top-post.

Xiaoshen Li wrote:
[Question: How to use strtod(), especially the char** parameter]

I found the solution. Sorry for bothering.

endptr will point to the string(==pointer to a char array)

<snip>

Here is an example how to use strtol(); you should be able
to adapt it to strtod():
http://home.att.net/~jackklein/c/code/strtol.html

Cheers
Michael