string_utils.sgml

This GLib version 2.16.1. GLib is the low-level core library that forms the basis for projects such

<!-- ##### SECTION Title ##### -->
String Utility Functions

<!-- ##### SECTION Short_Description ##### -->
various string-related functions

<!-- ##### SECTION Long_Description ##### -->
<para>
This section describes a number of utility functions for creating,
duplicating, and manipulating strings.
</para>
<para>
Note that the functions g_printf(), g_fprintf(), g_sprintf(), g_snprintf(),
g_vprintf(), g_vfprintf(), g_vsprintf() and g_vsnprintf() are declared in 
the header <filename>gprintf.h</filename> which is <emphasis>not</emphasis>
included in <filename>glib.h</filename> (otherwise using 
<filename>glib.h</filename> would drag in <filename>stdio.h</filename>), so
you'll have to explicitly include <literal>&lt;glib/gprintf.h&gt;</literal> 
in order to use the GLib printf() functions. 
</para>
<para id="string-precision">
While you may use the printf() functions to format UTF-8 strings, notice that
the precision of a <literal>&percnt;Ns</literal> parameter is interpreted as the
number of <emphasis>bytes</emphasis>, not <emphasis>characters</emphasis> to print.
On top of that, the GNU libc implementation of the printf() functions has the "feature"
that it checks that the string given for the <literal>&percnt;Ns</literal> parameter
consists of a whole number of characters in the current encoding. So, unless you
are sure you are always going to be in an UTF-8 locale or your know your text is restricted 
to ASCII, avoid using <literal>&percnt;Ns</literal>.
If your intention is to format strings for a certain number of columns, then 
<literal>&percnt;Ns</literal> is not a correct solution anyway, since it fails to take 
wide characters (see g_unichar_iswide()) into account.
</para>

<!-- ##### SECTION See_Also ##### -->
<para>

</para>

<!-- ##### SECTION Stability_Level ##### -->


<!-- ##### FUNCTION g_strdup ##### -->
<para>
Duplicates a string.
If @str is %NULL it returns %NULL.
The returned string should be freed when no longer needed.
</para>

@str: the string to duplicate.
@Returns: a newly-allocated copy of @str.


<!-- ##### FUNCTION g_strndup ##### -->
<para>

</para>

@str: 
@n: 
@Returns: 


<!-- ##### FUNCTION g_strdupv ##### -->
<para>
</para>

@str_array: 
@Returns: 


<!-- ##### FUNCTION g_strnfill ##### -->
<para>

</para>

@length: 
@fill_char: 
@Returns: 


<!-- ##### FUNCTION g_stpcpy ##### -->
<para>

</para>

@dest: 
@src: 
@Returns: 


<!-- ##### FUNCTION g_strstr_len ##### -->
<para>

</para>

@haystack: 
@haystack_len: 
@needle: 
@Returns: 


<!-- ##### FUNCTION g_strrstr ##### -->
<para>

</para>

@haystack: 
@needle: 
@Returns: 


<!-- ##### FUNCTION g_strrstr_len ##### -->
<para>

</para>

@haystack: 
@haystack_len: 
@needle: 
@Returns: 


<!-- ##### FUNCTION g_str_has_prefix ##### -->
<para>

</para>

@str: 
@prefix: 
@Returns: 


<!-- ##### FUNCTION g_str_has_suffix ##### -->
<para>

</para>

@str: 
@suffix: 
@Returns: 


<!-- ##### FUNCTION g_strlcpy ##### -->
<para>
Portability wrapper that calls strlcpy() on systems which have it, and emulates
strlcpy() otherwise. Copies @src to @dest; @dest is guaranteed to be
nul-terminated; @src must be nul-terminated; @dest_size is the buffer size, not
the number of chars to copy. Caveat: strlcpy() is supposedly more secure than
strcpy() or strncpy(), but if you really want to avoid screwups, g_strdup() is
an even better idea.
</para>

@dest: destination buffer
@src: source buffer
@dest_size: length of @dest in bytes
@Returns: length of @src


<!-- ##### FUNCTION g_strlcat ##### -->
<para>
Portability wrapper that calls strlcat() on systems which have it, and emulates it otherwise. 
Appends nul-terminated @src string to @dest, guaranteeing
nul-termination for @dest. The total size of @dest won't exceed
@dest_size. Caveat: this is supposedly a more secure alternative to strcat() or
strncat(), but for real security g_strconcat() is harder to mess up.
</para>

@dest: destination buffer, already containing one nul-terminated string
@src: source buffer
@dest_size: length of @dest buffer in bytes (not length of existing string inside @dest)
@Returns: length of @src plus initial length of string in @dest


<!-- ##### FUNCTION g_strdup_printf ##### -->
<para>
Similar to the standard C sprintf() function
but safer, since it calculates the maximum space required and allocates
memory to hold the result.
The returned string should be freed when no longer needed.
</para>

@format: a standard printf() format string, but notice 
  <link linkend="string-precision">string precision pitfalls</link>.
@Varargs: the parameters to insert into the format string.
@Returns: a newly-allocated string holding the result.


<!-- ##### FUNCTION g_strdup_vprintf ##### -->
<para>
Similar to the standard C vsprintf() function
but safer, since it calculates the maximum space required and allocates
memory to hold the result.
The returned string should be freed when no longer needed.
</para>
<para>
See also g_vasprintf(), which offers the same functionality, but additionally
returns the length of the allocated string. 
</para>

@format: a standard printf() format string, but notice 
  <link linkend="string-precision">string precision pitfalls</link>.
@args: the list of parameters to insert into the format string.
@Returns: a newly-allocated string holding the result.


<!-- ##### FUNCTION g_printf ##### -->
<para>

</para>

@format: 
@Varargs: 
@Returns: 


<!-- ##### FUNCTION g_vprintf ##### -->
<para>

</para>

@format: 
@args: 
@Returns: 


<!-- ##### FUNCTION g_fprintf ##### -->
<para>

</para>

@file: 
@format: 
@Varargs: 
@Returns: 


<!-- ##### FUNCTION g_vfprintf ##### -->
<para>

</para>

@file: 
@format: 
@args: 
@Returns: 


<!-- ##### FUNCTION g_sprintf ##### -->
<para>

</para>

@string: 
@format: 
@Varargs: 
@Returns: 


<!-- ##### FUNCTION g_vsprintf ##### -->
<para>

</para>

@string: 
@format: 
@args: 
@Returns: 


<!-- ##### FUNCTION g_snprintf ##### -->
<para>
</para>

@string: 
@n: 
@format: 
@Varargs: 
@Returns: 


<!-- ##### FUNCTION g_vsnprintf ##### -->
<para>
</para>

@string: 
@n: 
@format: 
@args: 
@Returns: 


<!-- ##### FUNCTION g_vasprintf ##### -->
<para>

</para>

@string: 
@format: 
@args: 
@Returns: 


<!-- ##### FUNCTION g_printf_string_upper_bound ##### -->
<para>
Calculates the maximum space needed to store the output of the sprintf() 
function.
</para>

@format: the format string. See the printf() documentation.
@args: the parameters to be inserted into the format string.
@Returns: the maximum space needed to store the formatted string.


<!-- ##### FUNCTION g_ascii_isalnum ##### -->
<para>
Determines whether a character is alphanumeric.
</para>
<para>
Unlike the standard C library isalnum() function, this only
recognizes standard ASCII letters and ignores the locale, returning
%FALSE for all non-ASCII characters. Also unlike the standard
library function, this takes a <type>char</type>, not an <type>int</type>, 
so don't call it on %EOF but no need to cast to #guchar before passing a 
possibly non-ASCII character in.
</para>

@c: any character
@Returns: %TRUE if @c is an ASCII alphanumeric character


<!-- ##### FUNCTION g_ascii_isalpha ##### -->
<para>
Determines whether a character is alphabetic (i.e. a letter).
</para>
<para>
Unlike the standard C library isalpha() function, this only
recognizes standard ASCII letters and ignores the locale, returning
%FALSE for all non-ASCII characters. Also unlike the standard
library function, this takes a <type>char</type>, not an <type>int</type>, 
so don't call it on %EOF but no need to cast to #guchar before passing a 
possibly non-ASCII character in.
</para>

@c: any character
@Returns: %TRUE if @c is an ASCII alphabetic character


<!-- ##### FUNCTION g_ascii_iscntrl ##### -->
<para>
Determines whether a character is a control character.
</para>
<para>
Unlike the standard C library iscntrl() function, this only
recognizes standard ASCII control characters and ignores the locale,
returning %FALSE for all non-ASCII characters. Also unlike the standard
library function, this takes a <type>char</type>, not an <type>int</type>, 
so don't call it on %EOF but no need to cast to #guchar before passing a 
possibly non-ASCII character in.
</para>

@c: any character
@Returns: %TRUE if @c is an ASCII control character.


<!-- ##### FUNCTION g_ascii_isdigit ##### -->
<para>
Determines whether a character is digit (0-9).
</para>
<para>
Unlike the standard C library isdigit() function,
this takes a <type>char</type>, not an <type>int</type>, so don't call it
on %EOF but no need to cast to #guchar before passing a possibly
non-ASCII character in.
</para>

@c: any character
@Returns: %TRUE if @c is an ASCII digit.


<!-- ##### FUNCTION g_ascii_isgraph ##### -->
<para>
Determines whether a character is a printing character and not a space.
</para>
<para>
Unlike the standard C library isgraph() function, 
this only recognizes standard ASCII characters and ignores the locale, 
returning %FALSE for all non-ASCII characters. Also unlike the standard
library function, this takes a <type>char</type>, not an <type>int</type>, 
so don't call it on %EOF but no need to cast to #guchar before passing a 
possibly non-ASCII character in.
</para>

@c: any character
@Returns: %TRUE if @c is an ASCII printing character other than space.


<!-- ##### FUNCTION g_ascii_islower ##### -->
<para>
Determines whether a character is an ASCII lower case letter.
</para>
<para>
Unlike the standard C library islower() function, 
this only recognizes standard ASCII letters and ignores the locale,
returning %FALSE for all non-ASCII characters. Also unlike the standard
library function, this takes a <type>char</type>, not an <type>int</type>, 
so don't call it on %EOF but no need to worry about casting to #guchar 
before passing a possibly non-ASCII character in.
</para>

@c: any character
@Returns: %TRUE if @c is an ASCII lower case letter


<!-- ##### FUNCTION g_ascii_isprint ##### -->
<para>
Determines whether a character is a printing character.
</para>
<para>
Unlike the standard C library isprint() function, 
this only recognizes standard ASCII characters and ignores the locale, 
returning %FALSE for all non-ASCII characters. Also unlike the standard
library function, this takes a <type>char</type>, not an <type>int</type>, 
so don't call it on %EOF but no need to cast to #guchar before passing a 
possibly non-ASCII character in.
</para>

@c: any character
@Returns: %TRUE if @c is an ASCII printing character.


<!-- ##### FUNCTION g_ascii_ispunct ##### -->
<para>
Determines whether a character is a punctuation character.
</para>
<para>
Unlike the standard C library ispunct() function, 
this only recognizes standard ASCII letters and ignores the locale, 
returning %FALSE for all non-ASCII characters. Also unlike the standard
library function, this takes a <type>char</type>, not an <type>int</type>, 
so don't call it on %EOF but no need to cast to #guchar before passing a 
possibly non-ASCII character in.
</para>

@c: any character
@Returns: %TRUE if @c is an ASCII punctuation character.


<!-- ##### FUNCTION g_ascii_isspace ##### -->
<para>
Determines whether a character is a white-space character.
</para>
<para>
Unlike the standard C library isspace() function, 
this only recognizes standard ASCII white-space and ignores the locale, 
returning %FALSE for all non-ASCII characters. Also unlike the standard
library function, this takes a <type>char</type>, not an <type>int</type>, 
so don't call it on %EOF but no need to cast to #guchar before passing a 
possibly non-ASCII character in.
</para>

@c: any character
@Returns: %TRUE if @c is an ASCII white-space character


<!-- ##### FUNCTION g_ascii_isupper ##### -->
<para>
Determines whether a character is an ASCII upper case letter.
</para>
<para>
Unlike the standard C library isupper() function, 
this only recognizes standard ASCII letters and ignores the locale,