ATOF(3P) POSIX Programmer's Manual ATOF(3P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
Linux manual page for details of Linux behavior), or the interface may
not be implemented on Linux.
NAMEatof - convert a string to a double-precision number
double atof(const char *str);
The call atof(str) shall be equivalent to:
except that the handling of errors may differ. If the value cannot be
represented, the behavior is undefined.
The atof() function shall return the converted value if the value can
No errors are defined.
The following sections are informative.
The atof() function is subsumed by strtod() but is retained because it
is used extensively in existing code. If the number is not known to be
in range, strtod() should be used because atof() is not required to
perform any error checking.
SEE ALSOstrtod(), the Base Definitions volume of IEEE Std 1003.1-2001,
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 ATOF(3P)