icon Top 9 categories map      RocketAware > man pages >


Tips: Browse or Search all pages for efficient awareness of more than 6000 of the most popular reusable and open source applications, functions, libraries, and FAQs.

The "RKT couplings" below include links to source code, updates, additional information, advice, FAQs, and overviews.


Search all pages


By activity
Professions, Sciences, Humanities, Business, ...

User Interface
Text-based, GUI, Audio, Video, Keyboards, Mouse, Images,...

Text Strings
Conversions, tests, processing, manipulation,...

Integer, Floating point, Matrix, Statistics, Boolean, ...

Algorithms, Memory, Process control, Debugging, ...

Stored Data
Data storage, Integrity, Encryption, Compression, ...

Networks, protocols, Interprocess, Remote, Client Server, ...

Hard World
Timing, Calendar and Clock, Audio, Video, Printer, Controls...

File System
Management, Filtering, File & Directory access, Viewers, ...


RocketLink!--> Man page versions: OpenBSD FreeBSD RedHat Solaris Others

[ANSI C X3.159-1989]

STRTOUL(3)                OpenBSD Programmer's Manual               STRTOUL(3)

     strtoul, strtouq - convert a string to an unsigned long or uquad_t

     #include <stdlib.h>
     #include <limits.h>

     unsigned long
     strtoul(const char *nptr, char **endptr, int base);

     #include <sys/types.h>
     #include <stdlib.h>
     #include <limits.h>

     strtouq(const char *nptr, char **endptr, int base);

     The strtoul() function converts the string in nptr to an unsigned long
     value.  The strtouq() function converts the string in nptr to a u_quad_t
     value.  The conversion is done according to the given base, which must be
     a number between 2 and 36 inclusive or the special value 0.

     The string may begin with an arbitrary amount of white space (as deter-
     mined by isspace(3))  followed by a single optional `+' or `-' sign.  If
     base is zero or 16, the string may then include a `0x' prefix, and the
     number will be read in base 16; otherwise, a zero base is taken as 10
     (decimal) unless the next character is `0', in which case it is taken as
     8 (octal).

     The remainder of the string is converted to an unsigned long value in the
     obvious manner, stopping at the end of the string or at the first charac-
     ter that does not produce a valid digit in the given base.  (In bases
     above 10, the letter `A' in either upper or lower case represents 10, `B'
     represents 11, and so forth, with `Z' representing 35.)

     If endptr is non nil, strtoul() stores the address of the first invalid
     character in *endptr. If there were no digits at all, however, strtoul()
     stores the original value of nptr in *endptr. (Thus, if *nptr is not `\0'
     but **endptr is `\0' on return, the entire string was valid.)

     The strtoul() function returns the result of the conversion, unless the
     value would overflow, in which case ULONG_MAX is returned and errno is
     set to ERANGE. If there was a leading minus sign, strtoul() returns the
     (unsigned) negation of the absolute value of the number, unless the abso-
     lute value would overflow.  In this case, strtoul() returns ULONG_MAX and
     sets the global variable errno to ERANGE.

     There is no way to determine if strtoul() has processed a negative number
     (and returned an unsigned value) short of examining the string in nptr

     Ensuring that a string is a valid number (i.e., in range and containing
     no trailing characters) requires clearing errno beforehand explicitly
     since errno is not changed on a successful call to strtoul(), and the re-
     turn value of strtoul() cannot be used unambiguously to signal an error:

           char *ep;
           unsigned long ulval;


           errno = 0;
           ulval = strtoul(buf, &ep, 10);
           if (buf[0] == '\0' || *ep != '\0')
                   goto not_a_number;
           if (errno == ERANGE && ulval == ULONG_MAX)
                   goto out_of_range;

     This example will accept ``12'' but not ``12foo'' or ``12\n''. If trail-
     ing whitespace is acceptable, further checks must be done on *ep; alter-
     nately, use sscanf(3).

     [ERANGE]      The given string was out of range; the value converted has
                   been clamped.

     sscanf(3),  strtol(3)

     The strtoul() function conforms to ANSI X3.159-1989 (``ANSI C'').

     Ignores the current locale.

OpenBSD 2.6                      June 25, 1992                               2

Source: OpenBSD 2.6 man pages. Copyright: Portions are copyrighted by BERKELEY
SOFTWARE DESIGN, INC., The Regents of the University of California, Massachusetts
Institute of Technology, Free Software Foundation, FreeBSD Inc., and others.

(Corrections, notes, and links courtesy of RocketAware.com)

[Detailed Topics]
FreeBSD Sources for strtoul(3) functions
OpenBSD sources for strtoul(3)

[Overview Topics]

Up to: String-Integer-String conversions - Converting strings to and from integers. ascii to long, long to ascii, etc.

RocketLink!--> Man page versions: OpenBSD FreeBSD RedHat Solaris Others

[ANSI C X3.159-1989]

Rapid-Links: Search | About | Comments | Submit Path: RocketAware > man pages > strtoul.3/
RocketAware.com is a service of Mib Software
Copyright 1999, Forrest J. Cavalier III. All Rights Reserved.
We welcome submissions and comments