[#BloombergLP-bdlde-Utf8Util-advanceIfValid-09]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlde.adoc[bdlde]::xref:BloombergLP/bdlde/Utf8Util.adoc[Utf8Util]::advanceIfValid
:relfileprefix: ../../../
:mrdocs:

Advance past 0 or more consecutive _valid_ Unicode code points at the beginning of the specified `string` having the specified `length` (in bytes), until either the specified `numCodePoints` or `length` bytes have been traversed, or invalid UTF‐8 is encountered (whichever occurs first), and return the number of Unicode code points traversed. Set the specified `*status` to 0 if no invalid UTF‐8 is encountered, and to a value from the `ErrorStatus` `enum` otherwise. Set the specified `*result` to the address of the byte immediately following the last valid code point traversed, or to `string` if `length` or `numCodePoints` is 0. `string` need not be null‐terminated and can contain embedded null bytes, and `string` may be null if `0 == length` (see {Empty Input Strings}). The behavior is undefined unless `0 <= numCodePoints`. Note that the value returned will be in the range `[0 .. numCodePoints]`. Also note that `string` may contain less than `length` Unicode code points.

== Synopsis

Declared in `<bdlde_utf8util.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
static
xref:BloombergLP/bdlde/Utf8Util/IntPtr.adoc[IntPtr]
advanceIfValid(
    int* status,
    char const** result,
    char const* string,
    xref:BloombergLP/bdlde/Utf8Util/size_type.adoc[size_type] length,
    xref:BloombergLP/bdlde/Utf8Util/IntPtr.adoc[IntPtr] numCodePoints);
----


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